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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