c# - gridview data export to excel in asp.net

Question

i tried to transfer grid view data to excel .... But the output is a blank excel sheet.How to solve this problem?Is there any code to transfer grid view value to excel sheet with data base?

protected void btnexcel_Click1(object sender, EventArgs e)
{
    Response.Clear();
    Response.Buffer = true;
    Response.AddHeader("content-disposition", "attachment;filename=GridViewExport.xls");
    Response.Charset = "";
    Response.ContentType = "application/vnd.ms-excel";

    StringWriter sw = new StringWriter();
    HtmlTextWriter hw = new HtmlTextWriter(sw);

    gvdetails.AllowPaging = false;
    gvdetails.DataBind(); 
    gvdetails.HeaderRow.Style.Add("background-color", "#FFFFFF");
    gvdetails.HeaderRow.Cells[0].Style.Add("background-color", "green");
    gvdetails.HeaderRow.Cells[1].Style.Add("background-color", "green");
    gvdetails.HeaderRow.Cells[2].Style.Add("background-color", "green");
    for (int i = 0; i < gvdetails.Rows.Count;i++ )
    {
        GridViewRow row = gvdetails.Rows[i];
        row.BackColor = System.Drawing.Color.White;
        row.Attributes.Add("class", "textmode");
        if (i % 2 != 0)
        {
            row.Cells[0].Style.Add("background-color", "#C2D69B");
            row.Cells[1].Style.Add("background-color", "#C2D69B");
            row.Cells[2].Style.Add("background-color", "#C2D69B");
        }
    }

    string style = @"<style> .textmode { mso-number-format:@; } </style>"; 
    Response.Write(style); 

    Response.Output.Write(sw.ToString());
    Response.End();
}

Answer 1

Your sheet is blank because your string writer in null. Here is what may help

System.Web.UI.HtmlTextWriter htmlWrite =
    new HtmlTextWriter(stringWrite);

    GridView1.RenderControl(htmlWrite);

Here is the full code

protected void Button1_Click(object sender, EventArgs e)
{
    Response.Clear();

    Response.AddHeader("content-disposition", "attachment;
    filename=FileName.xls");


    Response.ContentType = "application/vnd.xls";

    System.IO.StringWriter stringWrite = new System.IO.StringWriter();

    System.Web.UI.HtmlTextWriter htmlWrite =
    new HtmlTextWriter(stringWrite);

    GridView1.RenderControl(htmlWrite);

    Response.Write(stringWrite.ToString());

    Response.End();

}