在那里，可以得到字符串中的字符的第三个索引的命令？例如：

is there a command that can get the third index of a character in a string? For example:

error: file.ext: line 10: invalid command [test:)]

在上面这句话，我想第三结肠指数，旁边10.我怎么能做到这一点的呢？我知道string.IndexOf和string.LastIndexOf的，但在这种情况下，我希望得到一个字符的索引时，使用它的第三次。

In the above sentence, I want to the index of the 3rd colon, the one next to the 10. How could I do that? I know of string.IndexOf and string.LastIndexOf, but in this case I want to get the index of a character when it is used the third time.

推荐答案

String.IndexOf 将让你在第一的指标，但重载给人一种起点。所以，你可以使用第一个的IndexOf 加一为出发点，为下一次的结果。然后只累积索引的足够次数：

String.IndexOf will get you the index of the first, but has overloads giving a starting point. So you can use a the result of the first IndexOf plus one as the starting point for the next. And then just accumulate indexes a sufficient number of times:

var offset = myString.IndexOf(':');
offset = myString.IndexOf(':', offset+1);
var result = myString.IndexOf(':', offset+1);

添加的错误处理，除非你知道 myString的至少包含三个冒号。

Add error handling unless you know that myString contains at least three colons.