C# 中英文字符串截取(全角半角处理)

 

/// <summary>
    /// 字符截取,中文一个字符两个字节处理
    /// </summary>
    /// <param name="str"></param>
    /// <param name="length"></param>
    /// <returns></returns>
    public string GetSubString(string str, int length)
    {
        Regex regex = new Regex("^[\u4e00-\u9fa5]$");
        StringBuilder sb = new StringBuilder();
        int nLength = 0;
        for (int i = 0; i < str.Length; i++)
        {
            nLength += Encoding.Default.GetByteCount(str[i].ToString());//全角长度2,半角长度1
            if (nLength > length)//当总长度超出要截取的长度，余下的字符不加
                break;
            sb.Append(str[i].ToString());
        }
        return sb.ToString();
    }