C#逐字字符串字面量– @用法介绍 _C#开发

在C＃中, 使用特殊符号创建逐字字符串@。 @被称为逐字标识符。如果一个字符串包含@作为前缀, 后跟双引号, 则编译器将该字符串标识为逐字字符串, 然后编译该字符串。 @符号的主要优点是告诉字符串构造函数忽略转义符和换行符。 @符号主要有以下三种用法：
使用1：
关键字作为标识符
该符号允许使用
关键字作为标识符
。 @符号是关键字的前缀, 因此编译器将关键字作为标识符, 没有任何错误, 如下例所示：
例子：

// C# program to illustrate // the use of @ by using keyword // as an identifier using System; public class GFG {// Main method static public void Main() {// Creating and initializing the array // here 'for' keyword is used as // an identifier by using @ symbol string [] @ for = { "C#" , "PHP" , "Java" , "Python" }; // as and for keywords is // as an identifier // using @ symbol foreach ( string @ as in @ for ) { Console.WriteLine( "Element of Array: {0}" , @ as ); } } }

输出如下：

Element of Array: C#Element of Array: PHPElement of Array: JavaElement of Array: Python

使用2：用于在字符串文字中打印转义序列, 以及在没有任何转义序列的字符串文字中使用换行符等。
如果有人将转义序列" \\"(用于反斜杠), " \ u"(Unicode转义序列), "\X"(十六进制转义序列)等, 而不使用@符号, 则这些字符串将由编译器自动解释。但是, ""(双引号)不是按字面意义解释的。它就像一个字符串插值。让我们看看带有@符号和不带有@符号的不同情况。
情况1：

// taking a string literal and // try to print double quotesstring str1 = """"; // printing output// this will give compile// time error as Unexpected // symbol `' Console.WriteLine(str1);

在上面的程序中, 双引号内的双引号作为字符串文字被解释为单引号。
情况2：

// taking a string literal prefixes// with @ and try to print double quotesstring str1 = @""""; // printing output// this will output as "Console.WriteLine(str1);

在上面的程序中, 输出是双引号(")不""
情况3：

// taking a string in which we are storing // some location of file but \Testing will // interpreted as eascape sequence \T // similarly \Nstring str1 = "\\C:\Testing\New\Target"; // printing str1// this will give compile time error as// Unrecognized escape sequence `\T'// Unrecognized escape sequence `\N'// Unrecognized escape sequence `\T'Console.WriteLine(str1);

情况4：

// taking a string and prefix literal with @ symbol. // Storing some location of file string str1 = @"\\C:\Testing\New\Target"; // printing str1 will give output as // \\C:\Testing\New\TargetConsole.WriteLine(str1);

程序：

// C# program to illustrate // the use of @ in terms of // escape sequences and new // line and tab using System; public class GFG {// Main method static public void Main() {// If you use the below commented // the part then this will give // Unrecognized escape sequence error // string S1 = "\\welcome \to lsbin \ portal \"; // Console.WriteLine("String 1 is :{0}", S1); // By using @ in the given string // it runs smoothly because // @ symbol tells the compiler to // ignore all escape sequences string S2 = @"\\welcome \to lsbin \ portal \" ; Console.WriteLine( "String 2 is: {0}" , S2); // printing new line character in string literal // but it will make the string to break // into a new line, see output string S3 = "This is \n C# non verbatim string" ; Console.WriteLine( "String 3 is :{0}" , S3); // By using @ symbol /n does not processed string S4 = @"This is \n C# verbatim string" ; Console.WriteLine( "String 4 is :{0}" , S4); // printing a string literal contains // tabs and new line without using // any escape sequence Console.WriteLine( @"Without Tab Sequence and New Line Character CC++JavaPython" ); } }

【C#逐字字符串字面量– @用法介绍】输出如下：

String 2 is: \\welcome \to lsbin \ portal \String 3 is :This is C# non verbatim stringString 4 is :This is \n C# verbatim stringWithout Tab Sequence and New Line CharacterCC++JavaPython