.NET截取指定长度字符超出部分以"..."代替

///   <summary>   
///   将指定字符串按指定长度进行剪切，   
///   </summary>   
///   <param   name= "Str "> 需要截断的字符串 </param>   
///   <param   name= "maxLength "> 字符串的最大长度 </param>   
///   <param   name= "endWith "> 超过长度的后缀 </param>   
///   <returns> 如果超过长度，返回截断后的新字符串加上后缀，否则，返回原字符串 </returns>   
public static string StringTruncat(string Str, int maxLength, string endWith)
{
    if (string.IsNullOrEmpty(Str))
    {
        return Str + endWith;
    }
    if (maxLength < 1)
    {
        return Str;
    }
    if (Str.Length > maxLength)
    {
        string strTmp = Str.Substring(0, maxLength);
        if (string.IsNullOrEmpty(endWith))
            return strTmp;
        else
            return strTmp + endWith;
    }
    return Str;
}