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  • C#中$的用法

     1 class Program
     2     {
     3         static void Main(string[] args)
     4         {
     5             string tbName = "User";
     6             string colName = "Id";
     7             long id = 5;
     8             string sql1 = string.Format("SELECT * FROM {0} WHERE {1} = {2}", tbName, colName, id);    //值:SELECT * FROM User WHERE Id = 5
     9             Console.WriteLine(sql1);
    10             string sql2 = $"SELECT * FROM {tbName} where {colName} = {id}"; //效果同sql1 //SELECT * FROM User WHERE Id = 5
    11             Console.WriteLine(sql2);
    12 
    13             string str1 = "a";
    14             string formatStr1 = $"{str1,5}";   //效果同:string.Format("{0,5}", str1);     //值:XXXXa
    15             Console.WriteLine(formatStr1); 
    16 
    17             DateTime dt1 = DateTime.Now;
    18             string formatDt1 = $"{dt1:yyyy}";   //效果同:string.Format("{0:yyyy}", dt1);     //值:2019
    19             Console.WriteLine(formatDt1);       //2019
    20 
    21             Console.ReadLine();
    22         }
    23     }

    C#中$的用法:是为了替代string.format();原先赋值需要占位符和变量,当需要拼接多个变量会造成语句过长等不易理解问题,$""是为了替代string.format(),可以把字符串中的C#变量{}包含起来达到识别C#变量的目的$"{id}";也支持表达式,使用$"{(你的表达式)}"

    参考博文(我的代码也来源于此,只是修正了下代码而已):https://www.cnblogs.com/hilolin/p/9123970.html#top

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  • 原文地址:https://www.cnblogs.com/nlh774/p/10272271.html
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