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

ClosedXML is a miracle, it's a great deal faster and easier to use.

var workbook = new XLWorkbook();//create the new book

var worksheet = workbook.Worksheets.Add("Computer Install");// Add a sheet
worksheet.Cell(1,1).Value = "PC Name";// (Row, column) write to a cell

workbook.SaveAs(@"LIC documents.xlsx");// Save the book

You install using a nu Get package. https://www.nuget.org/packages/ClosedXML

Answer 2

Turn off ScreenUpdating before writing any data, Application.ScreenUpdating = FALSE then turn on at end of code = TRUE

Answer 3

I had similar problems when reading an extremely large excel file and it took over 2 hours using interop.

I tried using ClosedXml and the process took less than 10 seconds. ClosedXml

// To loop 
Sheet.Row(y).Cell(x).Value

Also keep in mind interop will not work on your server unless you have excel installed. ClosedXml does not need excel installed.

Answer 4

Use Value2 to make it fast; Show excel before filling data

Answer 5

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.

Answer 6

Excel interop is never going to be fast. You're basically remote-controlling an instance of the Excel application. You might have more success by creating a CSV file and then using Excel interop to convert this to a .xls or .xlsx file