How to download a generated excel file from your asp.net application

Question

I am building an asp.net website and I am constructing a Excel document based on some gridview data. I am using Microsoft.Office.Interop.Excel to construct it. I have tried to use a saveFileDialog box using System.Windows.Forms. Through my research online, I have learned that you can’t actually do this in an asp.net application? Everything works great in debugging mode, but when uploading it to the site, the page doesn't work at all. So my man question is, is it possible to to use a saveFileDialog box for an asp.net application? Does anyone know a good workaround for this? I will post my code that works great in debugging mode, but doesn't work when I upload it to my site. Thanks in advance for any help.

using System.Threading;
using Excel = Microsoft.Office.Interop.Excel;
using Microsoft.Office.Interop.Excel;
using System.Windows.Forms;

SaveFileDialog saveFileDialog1 = new SaveFileDialog();
Excel.Application xlApp = new Excel.Application();
Excel.Workbook xlWorkBook;
Excel.Worksheet xlWorkSheet;
object misValue = System.Reflection.Missing.Value;

public void someEvent()
{
    var t = new Thread(SaveFolder);
    t.IsBackground = true;
    t.SetApartmentState(ApartmentState.STA);
    t.Start();
}

public void SaveFolder()
{
    saveFileDialog1.Filter = "Sources (*.xls, *.xlsx)|*.xls*;*.xlsx"; 
    saveFileDialog1.ShowDialog();
    exportReport();
}

public void exportReport()
{
    xlWorkBook.SaveAs(@saveFileDialog1.FileName, Excel.XlFileFormat.xlWorkbookNormal, misValue, misValue, misValue, misValue, Excel.XlSaveAsAccessMode.xlExclusive, misValue, misValue, misValue, misValue, misValue);
    xlWorkBook.Close(true, misValue, misValue);
    xlApp.Quit();

    releaseObject(xlApp);
    releaseObject(xlWorkBook);
    releaseObject(xlWorkSheet);
}

public void releaseObject(object obj)
{
    try
    {
        System.Runtime.InteropServices.Marshal.ReleaseComObject(obj);
        obj = null;
    }
    catch (Exception ex)
    {
        obj = null;
        MessageBox.Show("Unable to release the Object " + ex.ToString());
    }
    finally
    {
        GC.Collect();
    }
} 

Answer 1

You can't show a dialog box on the server. There's nobody there to see it. Get rid of the whole saveFileDialog object and just call SaveAs with a generated filename in the server's file system that is guaranteed to be unique. Then transmit that file to your user.