C#获取字符串后几位数的方法

#region 获取后几位数 public string GetLastStr(string str,int num)
/// <summary>
/// 获取后几位数
/// </summary>
/// <param name="str">要截取的字符串</param>
/// <param name="num">返回的具体位数</param>
/// <returns>返回结果的字符串</returns>
public string GetLastStr(string str, int num)
{
  int count = 0;
  if (str.Length > num)
  {
 count = str.Length - num;
 str = str.Substring(count, num);
  }
  return str;
}
#endregion