Microsoft.Office.Interop.Excel really slow

Question

I am exporting a 1200 X 800 matrix (indexMatrix) to a excel file using the standard Microsoft.Office.Interop.Excel. The app works, just that it is really really really slow(

Answer 1

I am answering a little bit late sorry. I was working on my project and we had to use interop excel. And our data was too big, which was taking more than 1 minute with interop excel. We tried something else which is copy the all content of datagridview to clipboard, open an excel worksheet using interop excel, and paste the content to excel. It takes less than 1 second and exports our data perfectly.

DataGridView to string:

    var newline = System.Environment.NewLine;
    var tab = "\t";
    var clipboard_string = "";

    foreach (DataGridViewRow row in dgProjeler.Rows)
    {
        for (int i = 0; i < row.Cells.Count; i++)
        {
            if (i == (row.Cells.Count - 1))
                clipboard_string += row.Cells[i].Value + newline;
            else
                clipboard_string += row.Cells[i].Value + tab;
        }
    }

and copy the string to clipboard

        Clipboard.SetText(clipboard_string);

And open a worksheet, paste the content.

        Excel.Application app = new Excel.Application();
        app.Visible = true;
        Excel.Workbook wb = app.Workbooks.Add(1);
        Excel.Worksheet ws = (Excel.Worksheet)wb.Worksheets[1];
        // changing the name of active sheet
        ws.Name = "Exported from gridview";

        ws.Rows.HorizontalAlignment = HorizontalAlignment.Center;
        app.ActiveWindow.Activate();


        ws.Activate();
        ws.Paste();

        ws.Cells.EntireColumn.AutoFit();

It works perfectly on me, I hope it helps people who still couldn't find the solution.