截取中間字符

/// <summary>
/// 截取中間字符
/// </summary>
/// <param name="text">全字符串</param>
/// <param name="start">開始字符串 </param>
/// <param name="end">結束字符串 </param>
/// <returns></returns>
public string Substring(string text, string start, string end)
{
Regex rg = new Regex("(?<=(" + start + "))[.\\s\\S]*?(?=(" + end + "))", RegexOptions.Multiline | RegexOptions.Singleline);
string NameText = rg.Match(text).Value;
return NameText;
}