c#中字符串分割(新)

有时我们需将一个字符串用另一个字符串来分割成字符串字组。而C#中string.split只提供用char来分割。怎么办？
用的时候直接调用第一个函数

/// <summary>
  /// 将字符串分割成数组
  /// </summary>
  /// <param name="strSource"></param>
  /// <param name="strSplit"></param>
  /// <returns></returns>
  public string[] StringSplit(string strSource,string strSplit)
  {
   string[] strtmp = new string[1];
   int index = strSource.IndexOf(strSplit,0);
   if(index<0)
   {
    strtmp[0] = strSource;
    return strtmp;
   }
   else
   {
    strtmp[0] = strSource.Substring(0,index);
    return StringSplit(strSource.Substring(index+strSplit.Length),strSplit,strtmp);
   }
  }

递归得出string[]

 /// <summary>
  /// 采用递归将字符串分割成数组
  /// </summary>
  /// <param name="strSource"></param>
  /// <param name="strSplit"></param>
  /// <param name="attachArray"></param>
  /// <returns></returns>
  private string[] StringSplit(string strSource,string strSplit,string[] attachArray)
  {
   string[] strtmp = new string[attachArray.Length+1];
   attachArray.CopyTo(strtmp,0);

   int index = strSource.IndexOf(strSplit,0);
   if(index<0)
   {
    strtmp[attachArray.Length] = strSource;
    return strtmp;
   }
   else
   {
    strtmp[attachArray.Length] = strSource.Substring(0,index);
    return StringSplit(strSource.Substring(index+strSplit.Length),strSplit,strtmp);
   }   
  }