How to export DataGrid to an existing Excel sheet?

[Mark Chemali]

How can I export a DataGrid in ASP.NET to an existing Excel Workbook and place the gridview data in the first sheet?

Existing Excel workbook is found on c:/Project/Inm.xls

Below is my code to save the datagrid in excel:

    Protected Sub btnreport_Click(sender As Object, e As System.EventArgs) Handles btnreport.Click
 
 
        Response.Clear()
        Response.AddHeader("content-disposition", "attachment;filename=Invoice" & Now.ToString("ddMMyyyy_hhmmss") & ".xls")
        Dim mystringwriter As New IO.StringWriter()
        Dim myhtmltextwrite As New HtmlTextWriter(mystringwriter)
        GridView1.RenderControl(myhtmltextwrite)
        Response.Write(mystringwriter.ToString())
        Response.End()
 
    End Sub

[Mark Chemali]

All experts and no one was able to reply ! Wow..

For anyone who needs this code, here it is, please note that I didn't add a new sheet to the workbook, I kept the first sheet empty...

Thanks for whoever tried though !

Protected Sub btnreport_Click(sender As Object, e As System.EventArgs) Handles btnreport.Click
 
        Dim Excelapp = New Excel.Application()
 
        Dim Book As New Object
        Dim Sheet As New Object
'Open Existing Workbook
        Book = Excelapp.Workbooks.Open("C:\Project\Invoices.xls")
'Select first sheet in the workbook and work on it
        Book.Worksheets(1).Select()
'Get the rows in the datagrid but not the Header row
        For i As Integer = 0 To GridView1.Rows.Count - 1
            Dim row As GridViewRow = GridView1.Rows(i)
            For j As Integer = 0 To row.Cells.Count - 1
                Dim s As Integer = 1 + i
                Excelapp.Cells(s + 1, j + 1) = row.Cells(j).Text
            Next
        Next
'Save new book with the name "Invoice" + today's date and time
        Book.saveas("C:\Project" & "Invoice" & Now.ToString("ddMMyyyy_hhmmss") & ".xls")
 
        Excelapp.Quit()
 
 
    End Sub