C# 中英文混合字符串截取

/// <summary>
/// 截取中英文混合字符串
/// </summary>
/// <param name="text">字符文本</param>
/// <param name="length">截取长度</param>
/// <param name="replacetxt">replacetxt替换的多余字符</param>
/// <returns></returns>
public string GetString(string text, int length, string replacetxt)
{
int strLength = 0;
StringBuilder strb = new StringBuilder();
char[] Temp = text.ToCharArray();
for (int i = 0; i != Temp.Length; i++)
{
if (strLength >= length) //

{
strb.Append(replacetxt);
break;
}
else
{
if (((int)Temp[i]) < 255) //大于255的都是汉字或者特殊字符
{
strLength++;
}
else
{
strLength = strLength + 2;
}
strb.Append(Temp[i]);
}
}
return strb.ToString();
}