hpyhgz的专栏

C#语言参考 目录 1. 介绍....................................................................................................................................................................1 1.1 Hello, world..................................................................................................................................................1 1.2 类型..............................................................................................................................................................2 1.2.1 预定义类型...........................................................................................................................................3 1.2.2 转换.......................................................................................................................................................5 1.2.3 数组类型...............................................................................................................................................6 1.2.4 类型系统一致.......................................................................................................................................7 1.3 变量和参数..................................................................................................................................................8 1.4 自动内存管理............................................................................................................................................11 1.5 表达式........................................................................................................................................................13 1.6 声明............................................................................................................................................................15 1.7 类................................................................................................................................................................18 1.7.1 常数.....................................................................................................................................................20 1.7.2 域.........................................................................................................................................................20 1.7.3 方法.....................................................................................................................................................21 1.7.4 属性.....................................................................................................................................................22 1.7.5 事件.....................................................................................................................................................23 1.7.6 操作符.................................................................................................................................................24 1.7.7 索引.....................................................................................................................................................25 1.7.8 实例构造函数.....................................................................................................................................26 1.7.9 析构函数.............................................................................................................................................27 1.7.10 静态构造函数...................................................................................................................................27 1.7.11 继承...................................................................................................................................................28 1.8 结构............................................................................................................................................................29 1.9 接口............................................................................................................................................................30 1.10 代表..........................................................................................................................................................31 1.11 联合..........................................................................................................................................................32 1.12 名称空间和集合......................................................................................................................................32 1.13 版本..........................................................................................................................................................34 1.14 特征..........................................................................................................................................................36 2. 语法结构..........................................................................................................................................................39 2.1 翻译的阶段................................................................................................................................................39 2.2 文法符号....................................................................................................................................................39 2.3 预处理........................................................................................................................................................40 2.3.1 预处理声明.........................................................................................................................................40 2.3.2 #if, #elif, #else, #endif..........................................................................................................................41 2.3.3 预处理控制行.....................................................................................................................................42 2.3.4 #line.....................................................................................................................................................43 2.3.5 预处理标识符.....................................................................................................................................43 2.3.6 预处理表达式.....................................................................................................................................43 2.3.7 与空白交互作用.................................................................................................................................44 2.4 语法分析....................................................................................................................................................45 Confidential Material – Copyright  Microsoft Corporation 1999-2000. All Rights Reserved. iii C# LANGUAGE REFERENCE 2.4.1 输入.....................................................................................................................................................45 2.4.2 输入字符.............................................................................................................................................45 2.4.3 行结束符.............................................................................................................................................45 2.4.4 注释.....................................................................................................................................................45 2.4.5 空白.....................................................................................................................................................46 2.4.6 标记.....................................................................................................................................................47 2.5 句法分析....................................................................................................................................................47 2.5.1 标识符.................................................................................................................................................47 2.5.2 关键字.................................................................................................................................................48 2.5.3 数据符号.............................................................................................................................................48 2.5.4 操作符和标点.....................................................................................................................................53 2.5.5 Unicode 字符转意字符序列................................................................................................................53 3. 基本概念..........................................................................................................................................................55 3.1 声明............................................................................................................................................................55 3.2 成员............................................................................................................................................................57 3.2.1 名称空间成员.....................................................................................................................................57 3.2.2 结构成员.............................................................................................................................................57 3.2.3 枚举成员.............................................................................................................................................57 3.2.4 类成员.................................................................................................................................................58 3.2.5 接口成员.............................................................................................................................................58 3.2.6 数组成员.............................................................................................................................................58 3.2.7 代表成员.............................................................................................................................................58 3.3 成员访问....................................................................................................................................................58 3.3.1 声明可访问性.....................................................................................................................................58 3.3.2 可访问性域.........................................................................................................................................59 3.3.3 保护的访问.........................................................................................................................................61 3.3.4 可访问性约束.....................................................................................................................................62 3.4 签名和重载................................................................................................................................................62 3.5 范围............................................................................................................................................................63 3.5.1 名称隐藏.............................................................................................................................................65 3.6 名称空间或类型名称................................................................................................................................67 3.6.1 合格的名称.........................................................................................................................................68 4. 类型..................................................................................................................................................................69 4.1 数值类型....................................................................................................................................................69 4.1.1 默认构造函数.....................................................................................................................................70 4.1.2 结构类型.............................................................................................................................................71 4.1.3 简单类型.............................................................................................................................................71 4.1.4 整数类型.............................................................................................................................................72 4.1.5 浮点类型.............................................................................................................................................73 4.1.6 十进制类型.........................................................................................................................................74 4.1.7 布尔类型...........................................................................................................................................74 4.1.8 枚举类型.............................................................................................................................................74 4.2 引用类型....................................................................................................................................................74 4.2.1 类类型.................................................................................................................................................75 iv Confidential Material – Copyright  Microsoft Corporation 1999-2000. All Rights Reserved. Table of Contents 4.2.2 对象类型.............................................................................................................................................75 4.2.3 字符串类型.........................................................................................................................................75 4.2.4 接口类型.............................................................................................................................................76 4.2.5 数组类型.............................................................................................................................................76 4.2.6 代表类型.............................................................................................................................................76 4.3 包装和解包................................................................................................................................................76 4.3.1 包装转换.............................................................................................................................................76 4.3.2 解包转换.............................................................................................................................................77 5. 变量..................................................................................................................................................................79 5.1 变量类型....................................................................................................................................................79 5.1.1 静态变量.............................................................................................................................................79 5.1.2 实例变量.............................................................................................................................................79 5.1.3 数组元素.............................................................................................................................................80 5.1.4 数值参数.............................................................................................................................................80 5.1.5 引用参数.............................................................................................................................................80 5.1.6 输出参数.............................................................................................................................................80 5.1.7 局部变量.............................................................................................................................................81 5.2 默认值........................................................................................................................................................81 5.3 明确赋值....................................................................................................................................................81 5.3.1 初始赋值变量.....................................................................................................................................83 5.3.2 非初始赋值变量.................................................................................................................................84 5.4 变量引用....................................................................................................................................................84 6. 转换..................................................................................................................................................................85 6.1 隐式转换....................................................................................................................................................85 6.1.1 同一性转换.........................................................................................................................................85 6.1.2 隐式数值转换.....................................................................................................................................85 6.1.3 隐式枚举转换.....................................................................................................................................86 6.1.4 隐式引用转换.....................................................................................................................................86 6.1.5 转换.....................................................................................................................................................86 6.1.6 隐式常数表达式转换..........................................................................................................................86 6.1.7 用户自定义隐式转换..........................................................................................................................87 6.2 显式转换....................................................................................................................................................87 6.2.1 显式数值转换.....................................................................................................................................87 6.2.2 显式枚举类型转换..............................................................................................................................88 6.2.3 显式引用类型转换..............................................................................................................................88 6.2.4 解包转换.............................................................................................................................................89 6.2.5 用户自定义显式转换..........................................................................................................................89 6.3 标准转换....................................................................................................................................................89 6.3.1 标准隐式转换.....................................................................................................................................89 6.3.2 标准显式转换.....................................................................................................................................90 6.4 用户定义转换............................................................................................................................................90 6.4.1 允许的用户自定义转换.......................................................................................................................90 6.4.2 用户自定义转换的取值.......................................................................................................................90 6.4.3 用户自定义隐式转换..........................................................................................................................91 Confidential Material – Copyright  Microsoft Corporation 1999-2000. All Rights Reserved. v C# LANGUAGE REFERENCE 6.4.4 用户自定义显式类型转换...................................................................................................................91 7. 表达式..............................................................................................................................................................93 7.1 表达式分类................................................................................................................................................93 7.1.1 表达式的数值.....................................................................................................................................94 7.2 操作符........................................................................................................................................................94 7.2.1 操作符优先级和结合顺序...................................................................................................................94 7.2.2 操作符重载.........................................................................................................................................96 7.2.3 一元操作符重载分析..........................................................................................................................97 7.2.4 二元操作符重载分析..........................................................................................................................97 7.2.5 候选用户定义操作符..........................................................................................................................98 7.2.6 数字升级.............................................................................................................................................98 7.3 成员查询....................................................................................................................................................99 7.3.1 基类型...............................................................................................................................................100 7.4 函数成员..................................................................................................................................................100 7.4.1 参数列表...........................................................................................................................................102 7.4.2 重载分析...........................................................................................................................................103 7.4.3 功能成员调用...................................................................................................................................105 7.4.4 虚拟函数成员查找............................................................................................................................106 7.4.5 接口函数成员查找............................................................................................................................106 7.5 主要的表达式..........................................................................................................................................106 7.5.1 文字...................................................................................................................................................106 7.5.2 简单名称...........................................................................................................................................107 7.5.3 加括号的表达式...............................................................................................................................108 7.5.4 成员访问...........................................................................................................................................108 7.5.5 调用表达式.......................................................................................................................................110 7.5.6 元素访问...........................................................................................................................................112 7.5.7 This访问............................................................................................................................................113 7.5.8 基本访问...........................................................................................................................................114 7.5.9 递增和递减后缀操作符.....................................................................................................................114 7.5.10 new操作符......................................................................................................................................115 7.5.11 typeof操作符.............................................................................................................................119 7.5.12 sizeof操作符............................................................................................................................119 7.5.13 checked和unchecked操作符.................................................................................................120 7.6 一元表达式..............................................................................................................................................122 7.6.1 一元正值运算符...............................................................................................................................122 7.6.2 一元负值运算符...............................................................................................................................122 7.6.3 逻辑非运算符...................................................................................................................................123 7.6.4 按位求补运算符...............................................................................................................................123 7.6.5 间接运算符.......................................................................................................................................123 7.6.6 地址运算符.......................................................................................................................................123 7.6.7 前缀增量和减量运算符.....................................................................................................................123 7.6.8 强制类型转换表达式........................................................................................................................124 7.7 算术运算符..............................................................................................................................................125 7.7.1 乘法运算符.......................................................................................................................................125 vi Confidential Material – Copyright  Microsoft Corporation 1999-2000. All Rights Reserved. Table of Contents 7.7.2 除法运算符.......................................................................................................................................126 7.7.3 余数运算符.......................................................................................................................................127 7.7.4 加法运算符.......................................................................................................................................127 7.7.5 减法运算符.......................................................................................................................................129 7.8 移位运算符..............................................................................................................................................130 7.9 关系运算符..............................................................................................................................................131 7.9.1 整数比较运算符...............................................................................................................................132 7.9.2 浮点比较运算符...............................................................................................................................132 7.9.3 小数比较运算符...............................................................................................................................133 7.9.4 布尔相等运算符...............................................................................................................................133 7.9.5 枚举比较运算符...............................................................................................................................133 7.9.6 引用类型相等运算符........................................................................................................................133 7.9.7 字符串相等运算符............................................................................................................................135 7.9.8 代表相等运算符...............................................................................................................................135 7.9.9 is 运算符............................................................................................................................................135 7.10 逻辑运算符............................................................................................................................................136 7.10.1 整数逻辑运算符..............................................................................................................................136 7.10.2 枚举逻辑运算符..............................................................................................................................136 7.10.3 布尔逻辑运算符..............................................................................................................................137 7.11 条件逻辑运算符....................................................................................................................................137 7.11.1 布尔条件逻辑运算符.......................................................................................................................137 7.11.2 用户自定义的条件逻辑运算符.......................................................................................................138 7.12 条件运算符............................................................................................................................................138 7.13 赋值运算符............................................................................................................................................139 7.13.1 简单赋值.........................................................................................................................................139 7.13.2 组合赋值.........................................................................................................................................141 7.13.3 事件赋值.........................................................................................................................................142 7.14 表达式....................................................................................................................................................142 7.15 常量表达式............................................................................................................................................142 7.16 布尔表达式............................................................................................................................................143 8. 语句................................................................................................................................................................145 8.1 终点与可达性..........................................................................................................................................145 8.2 块 146 8.2.1 语句列表...........................................................................................................................................147 8.3 空语句......................................................................................................................................................147 8.4 标号语句..................................................................................................................................................148 8.5 声明语句..................................................................................................................................................148 8.5.1 局部变量声明...................................................................................................................................148 8.5.2 局部常量声明...................................................................................................................................149 8.6 表达式语句..............................................................................................................................................150 8.7 选择语句..................................................................................................................................................150 8.7.1 if语句................................................................................................................................................150 8.7.2 Switch 语句.......................................................................................................................................151 8.8 重复语句..................................................................................................................................................154 Confidential Material – Copyright  Microsoft Corporation 1999-2000. All Rights Reserved. vii C# LANGUAGE REFERENCE 8.8.1 while语句..........................................................................................................................................155 8.8.2 do语句...............................................................................................................................................155 8.8.3 for语句..............................................................................................................................................155 8.8.4 foreach语句.......................................................................................................................................157 8.9 跳转语句..................................................................................................................................................158 8.9.1 break语句..........................................................................................................................................158 8.9.2 continue语句.....................................................................................................................................159 8.9.3 goto语句............................................................................................................................................159 8.9.4 return语句.........................................................................................................................................160 8.9.5 throw语句.........................................................................................................................................160 8.10 try语句...................................................................................................................................................161 8.11 checked和unchecked语句....................................................................................................................163 8.12 lock语句................................................................................................................................................163 9. 名称空间........................................................................................................................................................165 9.1 编译单元..................................................................................................................................................165 9.2 名称空间声明..........................................................................................................................................165 9.3 使用指示..................................................................................................................................................166 9.3.1 使用别名指示...................................................................................................................................167 9.3.2 使用名称空间指示............................................................................................................................169 9.4 名称空间成员..........................................................................................................................................170 9.5 类型声明..................................................................................................................................................171 10. 类..................................................................................................................................................................173 10.1 类声明....................................................................................................................................................173 10.1.1 类修饰符.........................................................................................................................................173 10.1.2 类基础规范.....................................................................................................................................174 10.1.3 类主体.............................................................................................................................................176 10.2 类成员....................................................................................................................................................176 10.2.1 继承.................................................................................................................................................177 10.2.2 new修饰符......................................................................................................................................177 10.2.3 访问修饰符.....................................................................................................................................178 10.2.4 要素类型.........................................................................................................................................178 10.2.5 静态和实例成员..............................................................................................................................178 10.2.6 嵌套类型.........................................................................................................................................179 10.3 常数........................................................................................................................................................179 10.4 域............................................................................................................................................................180 10.4.1 静态和实例域.................................................................................................................................181 10.4.2 只读域.............................................................................................................................................182 10.4.3 域的初始化.....................................................................................................................................183 10.4.4 变量初始化函数..............................................................................................................................183 10.5 方法........................................................................................................................................................185 10.5.1 方法参数.........................................................................................................................................186 10.5.2 静态和实例方法..............................................................................................................................189 10.5.3 虚拟方法.........................................................................................................................................190 10.5.4 覆盖方法.........................................................................................................................................191 viii Confidential Material – Copyright  Microsoft Corporation 1999-2000. All Rights Reserved. Table of Contents 10.5.5 抽象方法.........................................................................................................................................193 10.5.6 外部方法.........................................................................................................................................194 10.5.7 方法主体.........................................................................................................................................195 10.5.8 方法重载.........................................................................................................................................195 10.6 属性........................................................................................................................................................195 10.6.1 静态属性.........................................................................................................................................196 10.6.2 虚拟属性.........................................................................................................................................196 10.6.3 覆盖属性.........................................................................................................................................197 10.6.4 抽象属性.........................................................................................................................................198 10.6.5 访问符.............................................................................................................................................198 10.7 事件........................................................................................................................................................203 10.8 索引........................................................................................................................................................206 10.8.1 索引重载.........................................................................................................................................209 10.8.2 虚拟索引.........................................................................................................................................209 10.8.3 覆盖索引.........................................................................................................................................209 10.8.4 抽象索引.........................................................................................................................................210 10.9 操作符....................................................................................................................................................210 10.9.1 一元操作符.....................................................................................................................................211 10.9.2 二元操作符.....................................................................................................................................211 10.9.3 转换操作符.....................................................................................................................................212 10.10 实例构造函数......................................................................................................................................213 10.10.1 构造函数初始化函数.....................................................................................................................214 10.10.2 实例变量初始化函数.....................................................................................................................214 10.10.3 构造函数执行...............................................................................................................................214 10.10.4 默认构造函数...............................................................................................................................216 10.10.5 私有构造函数...............................................................................................................................217 10.10.6 可选的构造函数参数.....................................................................................................................217 10.11 析构函数..............................................................................................................................................217 10.12 静态构造函数......................................................................................................................................218 10.12.1 类加载和初始化............................................................................................................................219 11. 结构..............................................................................................................................................................221 11.1 结构声明................................................................................................................................................221 11.1.1 结构修饰符.....................................................................................................................................221 11.1.2 接口.................................................................................................................................................221 11.1.3 结构体.............................................................................................................................................221 11.2 结构成员................................................................................................................................................221 11.3 结构例子................................................................................................................................................221 11.3.1 数据库整数类型..............................................................................................................................221 11.3.2 数据库布尔类型..............................................................................................................................223 12. 数组..............................................................................................................................................................225 12.1 数组类型................................................................................................................................................225 12.1.1 System.Array 类型...................................................................................................................226 12.2 数组创建................................................................................................................................................226 12.3 数组元素访问........................................................................................................................................226 Confidential Material – Copyright  Microsoft Corporation 1999-2000. All Rights Reserved. ix C# LANGUAGE REFERENCE 12.4 数组成员................................................................................................................................................226 12.5 数组协方差............................................................................................................................................226 12.6 数组初始化函数....................................................................................................................................227 13. 接口..............................................................................................................................................................229 13.1 接口声明................................................................................................................................................229 13.1.1 接口修饰符.....................................................................................................................................229 13.1.2 基本接口.........................................................................................................................................229 13.1.3 接口主体.........................................................................................................................................230 13.2 接口成员................................................................................................................................................230 13.2.1 接口方法.........................................................................................................................................231 13.2.2 接口属性.........................................................................................................................................231 13.2.3 接口事件.........................................................................................................................................232 13.2.4 接口索引.........................................................................................................................................232 13.2.5 接口成员访问.................................................................................................................................232 13.3 完全有效的接口成员名称.....................................................................................................................234 13.4 接口实现................................................................................................................................................234 13.4.1 显式接口成员实现程序...................................................................................................................235 13.4.2 接口映射.........................................................................................................................................237 13.4.3 接口实现程序继承...........................................................................................................................239 13.4.4 接口重新实现程序...........................................................................................................................240 13.4.5 抽象类和接口.................................................................................................................................242 14. 枚举..............................................................................................................................................................243 14.1 枚举声明................................................................................................................................................243 14.2 枚举成员................................................................................................................................................244 14.3 枚举数值和操作....................................................................................................................................246 15. 代表..............................................................................................................................................................247 15.1 代表声明................................................................................................................................................247 15.1.1 可合并的代表类型...........................................................................................................................248 15.2 代表实例化............................................................................................................................................248 15.3 多点传送代表........................................................................................................................................248 15.4 代表调用................................................................................................................................................248 16. 异常..............................................................................................................................................................249 16.1 异常的产生............................................................................................................................................249 16.2 System.Exception 类......................................................................................................................249 16.3 异常怎样被处理....................................................................................................................................249 16.4 通用异常类............................................................................................................................................250 17. 属性..............................................................................................................................................................251 17.1 属性类....................................................................................................................................................251 17.1.1 AttributeUsage 属性..............................................................................................................251 17.1.2 位置的和名称的参数.......................................................................................................................252 17.1.3 属性参数类型.................................................................................................................................252 17.2 规范........................................................................................................................................................253 x Confidential Material – Copyright  Microsoft Corporation 1999-2000. All Rights Reserved. Table of Contents 17.3 属性实例................................................................................................................................................255 17.3.1 一个属性的编译..............................................................................................................................255 17.3.2 一个属性实例的运行时检索...........................................................................................................256 17.4 保留的属性............................................................................................................................................256 17.4.1 AttributeUsage 属性..............................................................................................................256 17.4.2 条件属性.........................................................................................................................................257 17.4.3 废弃的属性.....................................................................................................................................259 18. 危险代码......................................................................................................................................................261 18.1 危险代码................................................................................................................................................261 18.2 指针类型................................................................................................................................................261 19. 互用性..........................................................................................................................................................263 19.1 COMImport 属性................................................................................................................................263 19.2 COMRegisterFunction 属性............................................................................................................263 19.3 COMSourceInterfaces 属性............................................................................................................264 19.4 COMVisible 属性...............................................................................................................................264 19.5 DispId 属性.......................................................................................................................................264 19.6 DllImport 属性................................................................................................................................264 19.7 FieldOffset 属性.............................................................................................................................265 19.8 GlobalObject 属性...........................................................................................................................265 19.9 Guid 属性...........................................................................................................................................266 19.10 HasDefaultInterface 属性.........................................................................................................266 19.11 ImportedFromTypeLib 属性.........................................................................................................266 19.12 In 和 Out 属性.................................................................................................................................266 19.13 InterfaceType 属性.......................................................................................................................267 19.14 MarshalAs 属性...............................................................................................................................267 19.15 NoIDispatch 属性...........................................................................................................................268 19.16 NonSerialized 属性.......................................................................................................................268 19.17 Predeclared 属性...........................................................................................................................268 19.18 PreserveSig 属性...........................................................................................................................268 19.19 Serializable 属性.........................................................................................................................269 19.20 StructLayout 属性.........................................................................................................................269 19.21 TypeLibFunc 属性...........................................................................................................................269 19.22 TypeLibType 属性...........................................................................................................................269 19.23 TypeLibVar 属性.............................................................................................................................270 19.24 支持的枚举..........................................................................................................................................270 20. 参考..............................................................................................................................................................273