Export Grid View Data to Excel sheet

Question

I have a GridView and its retrieving all data from the SQL Server data base. and when i click a cmd button "Export to Excel" it just downloads an excel file. but i am getting an error  while opening the file, while other excel files are opening as usual.
My code is as below.
private void PrepareGridViewForExport(Control gv)
            LinkButton lb = new LinkButton();
            Literal l = new Literal();
            string name = String.Empty;
            for (int i = 0; i < gv.Controls.Count; i++)
                if (gv.Controls[i].HasControls())
                    PrepareGridViewForExport(gv.Controls[i]);
 private void Export_GridView()
            string attachment = "attachment; filename=ProductInfo.xls";
            Response.ClearContent();
            Response.AddHeader("content-disposition", attachment);
            Response.ContentType = "application/ms-excel";
            StringWriter sw1 = new StringWriter();
            HtmlTextWriter htw1 = new HtmlTextWriter(sw1);
            grd_ProdInfo.RenderControl(htw1);
            Response.Write(sw1.ToString());
            Response.End();
public override void VerifyRenderingInServerForm(Control control)
protected void cmdExport_Click(object sender, EventArgs e)
            PrepareGridViewForExport(grd_ProdInfo);
            Export_GridView();

Answer 1

I've been having problems myself opening up excel files when they are still attached to processes in Visual Studio.  ?We first need to determine if the excel file is good to determine if the problem is with the creating of the excel file or the reading
of the excel file.  Your problem may just be that the ecxcel file is no getting closed properly. So first try stopping visual Studio.  Then check the following
1) Check the task manager to make sure there is no excel.exe process running.  If there are any excel.exe running kill the process. 
2) Try opening up the excel file and see if the excel file contains any data and check if the data is in the correct locations.
3) Check the excel worksheet to make sure it is in a table format
       a) All the rows contain data in the primary key column (usually the first column)
       b) There are no blank rows of data before tthe last row of data
       c) There is a header row in row number 1 with text in some of the columns
       d) Check to see the number of worksheets in the workbook.
jdweng