C#导出excel

 //导出excel
    public void CreateExcel(DataTable dt, string FileName, string InvType)
    {
        Response.Clear();
        Response.Charset = "UTF-8";
        Response.Buffer = true;
        Response.ContentEncoding = System.Text.Encoding.GetEncoding("GB2312");
        Response.AppendHeader("Content-Disposition", "attachment;filename=\"" + System.Web.HttpUtility.UrlEncode(FileName, System.Text.Encoding.UTF8) + ".xls\"");
        string colHeaders = string.Empty;
        string ls_item = string.Empty;
        DataRow[] myRow = dt.Select();
        int i = 0;
        int cl = dt.Columns.Count;
        //写表头
        DataTable dtTitle = Datehelper.Question(InvType);
        for (int Q = 0; Q < dtTitle.Rows.Count; Q++)
        {
            string Value = dtTitle.Rows[Q]["QuestionId"].ToString() + "." + dtTitle.Rows[Q]["QuestionTitle"].ToString();
            if (Q == dtTitle.Rows.Count - 1)
            {
                ls_item += Value + "\n";
            }
            else
            {
                ls_item += Value + "\t";
            }

        }
        Response.Output.Write(ls_item);
        ls_item = string.Empty;


        //写数据
        foreach (DataRow row in myRow)
        {
            for (i = 0; i < cl; i++)
            {
                if (i == (cl - 1))
                {
                    ls_item += row[i].ToString() + "\n";
                }
                else
                {
                    ls_item += row[i].ToString() + "\t";
                }
            }
            Response.Output.Write(ls_item);
            ls_item = string.Empty;
        }
        Response.Output.Flush();
        Response.End();
        //HttpContext.Current.ApplicationInstance.CompleteRequest();
    }