C＃8.0中的内插逐字字符串

先决条件：字符串插值和逐字字符串

在C＃8.0之前，您可以按特定顺序一起使用字符串插值($)和逐字标识符(@)。这意味着当同时使用$令牌和@令牌时，必须$令牌必须出现在@令牌之前。如果在$令牌之前使用@令牌，则编译器将给您一个错误，如以下示例所示：

范例1：

// C# program to illustrate the use
// of interpolated verbatim strings
using System;
   
class GFG {
      
    // Main Method
    static void Main()
    {
        int Base = 10;
        int Height = 30;
        int area = (Base * Height) / 2;
   
        // Here, $ token appears before @ token
        Console.WriteLine("Finding the area of a triangle:");
        Console.WriteLine($@"Height = ""{Height}"" and Base = ""{Base}""");
        Console.WriteLine($@"Area = ""{area}""");
    }
}

输出：

Finding the area of a triangle:
Height = "30" and Base = "10"
Area = "150"

范例2：

// C# program to illustrate the use 
// of interpolated verbatim strings
using System;
   
class GFG {
      
    // Main Method
    static void Main()
    {
        int Base = 10;
        int Height = 30;
        int area = (Base * Height) / 2;
   
        // Here, @ token appears before $ token
        // But the compiler will give an error
        Console.WriteLine("Finding the area of a triangle:");
        Console.WriteLine(@ $"Height = ""{Height}"" and Base = ""{Base}""");                   
        Console.WriteLine(@ $"Area = ""{area}""");
    }
}

错误：

error CS1646: Keyword, identifier, or string expected after verbatim specifier: @
error CS1646: Keyword, identifier, or string expected after verbatim specifier: @

当我们在$令牌之前使用@令牌时，编译器将给出错误。此问题在C＃8.0中已解决，现在允许您在$令牌之前使用@令牌，或者在$令牌之前使用$令牌

$@"..."
Or
@$"..."

并且编译器不会给出错误。如下例所示：

例子：

// C# program to illustrate the use
// of interpolated verbatim strings
using System;
   
namespace Geeks {
      
class GFG {
      
    // Main Method
    static void Main(string[] args)
    {
        int Base = 40;
        int Height = 80;
        int area = (Base * Height) / 2;
        Console.WriteLine("Finding the area of a triangle:");
   
        // Here, $ token appears before @ token
        Console.WriteLine($@"Height = ""{Height}"" and Base = ""{Base}""");
   
        // Here, @ token appears before $ token
        Console.WriteLine(@$"Area = ""{area}""");
    }
}
}

输出：

Finding the area of a triangle:
Height = "80" and Base = "40"
Area = "1600"