在 C# 中的字符串中找到 {0} 是什么意思? [英] What does {0} mean when found in a string in C#?

问题描述

在这样的字典中:

Dictionary<string, string> openWith = new Dictionary<string, string>();

openWith.Add("txt", "notepad.exe");
openWith.Add("bmp", "paint.exe");
openWith.Add("dib", "paint.exe");
openWith.Add("rtf", "wordpad.exe");

Console.WriteLine("For key = "rtf", value = {0}.", openWith["rtf"]);

输出是:

对于 Key = "rtf" value = wordpad.exe

For Key = "rtf" value = wordpad.exe

{0} 是什么意思?

推荐答案

您正在打印一个格式化的字符串.{0} 表示在格式字符串后面插入第一个参数；在这种情况下，与键rtf"关联的值.

You are printing a formatted string. The {0} means to insert the first parameter following the format string; in this case the value associated with the key "rtf".

对于 String.Format，如果你有类似的东西，这是相似的

For String.Format, which is similar, if you had something like

//            Format string                    {0}           {1}
String.Format("This {0}.  The value is {1}.",  "is a test",  42 ) 

您将创建一个字符串This is a test.值为 42".

you'd create a string "This is a test. The value is 42".

您还可以使用表达式，并多次打印值:

You can also use expressions, and print values out multiple times:

//            Format string              {0} {1}  {2}
String.Format("Fib: {0}, {0}, {1}, {2}", 1,  1+1, 1+2) 

yielding "Fib: 1, 1, 2, 3"

yielding "Fib: 1, 1, 2, 3"

在 http://msdn.microsoft.com/en-us 查看更多信息/library/txafckwd.aspx，讨论复合格式.

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