//方法1

/// <summary>
/// 字符串截取函数，截取左边N个字符
/// </summary>
/// <param name="sInString">字符串</param>
/// <param name="iCutLength">截取个数</param>
/// <returns></returns>

public string CutStr(string sInString, int iCutLength)
{
string strCode = "unicode";//字符串使用的字符集.日语:Shift_JIS.简体中文:GBK.世界语:unicode

if (sInString == null || sInString.Length == 0 || iCutLength <= 0)
return "";
int iCount = System.Text.Encoding.GetEncoding(strCode).GetByteCount(sInString);//获取字符串的个数

if (iCount > iCutLength) //如果字符个数大于要截取的字符数.那么执行下面语句

{
int iLength = 0;
for (int i = 0; i < sInString.Length; i++)
{
int iCharLength = System.Text.Encoding.GetEncoding(strCode).GetByteCount(new char[] { sInString[i] });
iLength += iCharLength;
if (iLength == iCutLength)
{
sInString = sInString.Substring(0, i + 1);
sInString = sInString + "..."; //加省略号

break;
}
else if (iLength > iCutLength)
{
sInString = sInString.Substring(0, i);
break;
}
}
}
return sInString;
}