c#截取两个指定字符串中间的字符串

写法有很多，记录常用的两种：

1、正则表达式

1          public static string MidStrEx_New(string sourse, string startstr, string endstr)
2         {
3             Regex rg = new Regex("(?<=(" + startstr + "))[.\s\S]*?(?=(" + endstr + "))", RegexOptions.Multiline | RegexOptions.Singleline);
4             return rg.Match(sourse).Value;
5         }

2、利用字符串indexof截取：

 1         public static string MidStrEx(string sourse, string startstr, string endstr)
 2         {
 3             string result = string.Empty;
 4             int startindex, endindex;
 5             try
 6             {
 7                 startindex = sourse.IndexOf(startstr);
 8                 if (startindex == -1)
 9                     return result;
10                 string tmpstr = sourse.Substring(startindex + startstr.Length);
11                 endindex = tmpstr.IndexOf(endstr);           
12                 if (endindex == -1)
13                     return result;
14                 result = tmpstr.Remove(endindex);
15             }
16             catch (Exception ex)
17             {
18                 Log.WriteLog("MidStrEx Err:" + ex.Message);
19             }
20             return result;
21         }

就效率来说，测试了几次，方法2比方法1大约快10倍