protected void btnTest_Click(object sender, EventArgs e) {
        DownLoadFile("~/template.txt");
    }
    /// <summary>
    /// 下载文件
    /// </summary>
    /// <param name="fileName"></param>
    protected void DownLoadFile(string fileName) {


        try {
            string FullFileName = Server.MapPath(fileName);
            //FileName--要下载的文件名 
            FileInfo DownloadFile = new FileInfo(FullFileName);
            if (DownloadFile.Exists) {
                Response.Clear();
                Response.ClearHeaders();
                Response.Buffer = false;
                Response.ContentType = "application/octet-stream";
                Response.AppendHeader("Content-Disposition", "attachment;filename=" + ToHexString(DownloadFile.Name));
                Response.AppendHeader("Content-Length", DownloadFile.Length.ToString());
                Response.WriteFile(DownloadFile.FullName);
                Response.Flush();
                Response.End();
            }
        } catch {

        }


    }
    /// <summary>
    /// 为字符串中的非英文字符编码
    /// </summary>
    /// <param name="s"></param>
    /// <returns></returns>
    public string ToHexString(string s) {
        char[] chars = s.ToCharArray();
        StringBuilder builder = new StringBuilder();
        for (int index = 0; index < chars.Length; index++) {
            bool needToEncode = NeedToEncode(chars[index]);
            if (needToEncode) {
                string encodedString = ToHexString(chars[index]);
                builder.Append(encodedString);
            } else {
                builder.Append(chars[index]);
            }
        }

        return builder.ToString();
    }
    /// <summary>
    ///指定 一个字符是否应该被编码
    /// </summary>
    /// <param name="chr"></param>
    /// <returns></returns>
    private bool NeedToEncode(char chr) {
        string reservedChars = "$-_.+!*'(),@=&";

        if (chr > 127)
            return true;
        if (char.IsLetterOrDigit(chr) || reservedChars.IndexOf(chr) >= 0)
            return false;

        return true;
    }
    /// <summary>
    /// 为非英文字符串编码
    /// </summary>
    /// <param name="chr"></param>
    /// <returns></returns>
    private string ToHexString(char chr) {
        UTF8Encoding utf8 = new UTF8Encoding();
        byte[] encodedBytes = utf8.GetBytes(chr.ToString());
        StringBuilder builder = new StringBuilder();
        for (int index = 0; index < encodedBytes.Length; index++) {
            builder.AppendFormat("%{0}", Convert.ToString(encodedBytes[index], 16));
        }
        return builder.ToString();
    }