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();
}