C#String.Substring等效于StringBuilder？

Question

StringBuilder似乎没有Substring(start,len)方法......我在这里缺少什么？

Answer 1

StringBuilder类有一个特殊版本的ToString方法,它接受两个参数,与Substring(startIndex,length)完全相同.

 StringBuilder sb = new StringBuilder("This is a Test");
 string test = sb.ToString(10, 4);
 Console.WriteLine(test);   // result = Test