asp.net 查询，导出

using System;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;

using System.Globalization;
using System.IO;

public partial class _PIE_Project : System.Web.UI.Page
{

protected System.Data.SqlClient.SqlConnection SqlConnection1;
    protected System.Data.SqlClient.SqlDataAdapter SqlDataAdapter1;
    protected System.Data.DataSet DataSet1;
    protected System.Data.DataSet DataSet2;
    string Str_sql = "";

protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            P_ht.H_data P_data = new P_ht.H_data();
            P_data.sql_text1 = " SELECT [projectName], [WorkName], [PlanEndDate], [PlanStartDate] FROM [PJ_WorkPiece] ";
            Str_sql = P_data.sql_text1;
            P_data.select_tables();
            DataSet1 = P_data.DataSet8;
            Session["r1_PJ_WorkPiece"] = this.DataSet1;

this.GridView1.DataSource = DataSet1;
            this.GridView1.DataBind();

}
    }

protected void Btn_search_Click(object sender, EventArgs e)
    {
        string m_Where = "";
       
        //
        //// 正则表示式验证
        //

//
        //// check
        //
        ////  Response.Write("非标准日期");

DateTime dt1,dt2;

//
        if ((this.TextBox1.Text.Trim() != "") && (this.TextBox2.Text.Trim() != ""))
        {
            if (DateTime.TryParseExact(this.TextBox1.Text.Trim(), "yyyy-MM-dd", null, DateTimeStyles.None, out dt1))
            {
                //验证通过
            }
            else
            {
                ClientScriptManager scriptManager = ((Page)System.Web.HttpContext.Current.Handler).ClientScript;
                scriptManager.RegisterStartupScript(typeof(string), "", "alert('提示: 项目开始日期不是日期格式! ');", true);
                return;
            }

if (DateTime.TryParseExact(this.TextBox2.Text.Trim(), "yyyy-MM-dd", null, DateTimeStyles.None, out dt2))
            {
                //验证通过
            }
            else
            {
                ClientScriptManager scriptManager = ((Page)System.Web.HttpContext.Current.Handler).ClientScript;
                scriptManager.RegisterStartupScript(typeof(string), "", "alert('提示: 项目截止日期不是日期格式! ');", true);
                return;
            }

////
            if ((dt2 < dt1))
            {
                ClientScriptManager scriptManager = ((Page)System.Web.HttpContext.Current.Handler).ClientScript;
                scriptManager.RegisterStartupScript(typeof(string), "", "alert('提示: 项目开始日期不能大于项目截止日期! ');", true);
                return;
            }
            else
            {
                m_Where += (m_Where == "" ? "" : " and ") + " PlanStartDate Between '" + this.TextBox1.Text.Trim() + "' and '" + this.TextBox2.Text.Trim() + "'";
            }
        }
        else
        {
            if ((this.TextBox1.Text.Trim() != "") && (this.TextBox2.Text.Trim() == ""))
            {
                if (DateTime.TryParseExact(this.TextBox1.Text.Trim(), "yyyy-MM-dd", null, DateTimeStyles.None, out dt1))
                {
                    //验证通过
                    m_Where += (m_Where == "" ? "" : " and ") + " PlanStartDate > '" + this.TextBox1.Text.Trim() + "' ";
                }
                else
                {
                    ClientScriptManager scriptManager = ((Page)System.Web.HttpContext.Current.Handler).ClientScript;
                    scriptManager.RegisterStartupScript(typeof(string), "", "alert('提示: 项目开始日期不是日期格式! ');", true);
                    return;
                }
            }
            else
            {
                if ((this.TextBox1.Text.Trim() == "") && (this.TextBox2.Text.Trim() != ""))
                {
                    if (DateTime.TryParseExact(this.TextBox2.Text.Trim(), "yyyy-MM-dd", null, DateTimeStyles.None, out dt1))
                    {
                        //验证通过
                        m_Where += (m_Where == "" ? "" : " and ") + " PlanStartDate < '" + this.TextBox2.Text.Trim() + "' ";
                    }
                    else
                    {
                        ClientScriptManager scriptManager = ((Page)System.Web.HttpContext.Current.Handler).ClientScript;
                        scriptManager.RegisterStartupScript(typeof(string), "", "alert('提示: 项目开始日期不是日期格式! ');", true);
                        return;
                    }
                }
            }
        }

// project
        if (this.TextBox3.Text.Trim() != "")
        {
            m_Where += (m_Where == "" ? "" : " and ") + " projectName like '%" + this.TextBox3.Text.Trim() + "%' ";
        }

//
        //// Select
        //
        P_ht.H_data P_data = new P_ht.H_data();
        P_data.sql_text1 = " SELECT [projectName], [WorkName], [PlanEndDate], [PlanStartDate] FROM [PJ_WorkPiece] where " + m_Where + " ";
        Str_sql = P_data.sql_text1;
        P_data.select_tables();
        DataSet1 = P_data.DataSet8;
        Session["r1_PJ_WorkPiece"] = this.DataSet1;

this.GridView1.DataSource = DataSet1;
        this.GridView1.DataBind();

}

protected void GridView1_PageIndexChanging(object sender, GridViewPageEventArgs e)
    {
        GridView1.PageIndex = e.NewPageIndex;
        this.DataSet2 = new System.Data.DataSet();
        this.DataSet2 = (DataSet)Session["r1_PJ_WorkPiece"];
        this.GridView1.DataSource = this.DataSet2;
        this.GridView1.DataBind();
    }

protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
    {
        int i;
        //执行循环，保证每条数据都可以更新
        for (i = -1; i < GridView1.Rows.Count; i++)
        {
            //首先判断是否是数据行
            if (e.Row.RowType == DataControlRowType.DataRow)
            {
                //当鼠标停留时更改背景色
                e.Row.Attributes.Add("onmouseover", "c=this.style.backgroundColor;this.style.backgroundColor='#bcbf56'");
                //当鼠标移开时还原背景色
                e.Row.Attributes.Add("onmouseout", "this.style.backgroundColor=c");
            }
        }
    }

protected void btn_export_Click(object sender, EventArgs e)
    {
        HttpContext.Current.Response.Clear();
        HttpContext.Current.Response.Charset = "";
        HttpContext.Current.Response.ContentType = "application/vnd.ms-xls";
        StringWriter stringWrite = new StringWriter();
        HtmlTextWriter htmlWrite = new HtmlTextWriter(stringWrite);

DataGrid dg = new DataGrid();

//dg.DataSource = ds;
        this.DataSet2 = new System.Data.DataSet();
        this.DataSet2 = (DataSet)Session["r1_PJ_WorkPiece"];
        dg.DataSource = DataSet2;

dg.DataBind();
        dg.RenderControl(htmlWrite);
        //HttpContext.Current.Response.AddHeader("content-disposition", "attachment;filename="+HttpUtility.UrlEncode(excelName))
        HttpContext.Current.Response.AddHeader("content-disposition", "attachment;filename="+HttpUtility.UrlEncode("2015.xls"));
　　　　HttpContext.Current.Response.Write(stringWrite.ToString());
        HttpContext.Current.Response.End();
    }

}