Download Excel file via AJAX MVC

Question

I have a large(ish) form in MVC.

I need to be able to generate an excel file containing data from a subset of that form.

The tricky bit is that this shouldn

Answer 1

I was recently able to accomplish this in MVC (although there was no need to use AJAX) without creating a physical file and thought I'd share my code:

Super simple JavaScript function (datatables.net button click triggers this):

function getWinnersExcel(drawingId) {
    window.location = "/drawing/drawingwinnersexcel?drawingid=" + drawingId;
}

C# Controller code:

    public FileResult DrawingWinnersExcel(int drawingId)
    {
        MemoryStream stream = new MemoryStream(); // cleaned up automatically by MVC
        List winnerList = DrawingDataAccess.GetWinners(drawingId); // simple entity framework-based data retrieval
        ExportHelper.GetWinnersAsExcelMemoryStream(stream, winnerList, drawingId);

        string suggestedFilename = string.Format("Drawing_{0}_Winners.xlsx", drawingId);
        return File(stream, "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet.main+xml", suggestedFilename);
    }

In the ExportHelper class I do use a 3rd party tool (GemBox.Spreadsheet) to generate the Excel file and it has a Save to Stream option. That being said, there are a number of ways to create Excel files that can easily be written to a memory stream.

public static class ExportHelper
{
    internal static void GetWinnersAsExcelMemoryStream(MemoryStream stream, List winnerList, int drawingId)
    {

        ExcelFile ef = new ExcelFile();

        // lots of excel worksheet building/formatting code here ...

        ef.SaveXlsx(stream);
        stream.Position = 0; // reset for future read

     }
}

In IE, Chrome, and Firefox, the browser prompts to download the file and no actual navigation occurs.