Neil Neil - 1 year ago 231
ASP.NET (C#) Question

Download excel file from page via WebApi call

I'm trying to send a 9MB

file as a response from web api controller method. The user will click a button on the page and this will trigger the download via the browser.

Here's what I've got so far but it doesn't work however it doesn't throw any exceptions either.

public HttpResponseMessage ExportXls()
byte[] excelData = m_toolsService.ExportToExcelFile();

HttpResponseMessage result = new HttpResponseMessage(HttpStatusCode.OK);
var stream = new MemoryStream(excelData);
result.Content = new StreamContent(stream);
result.Content.Headers.ContentType = new MediaTypeHeaderValue("application/octet-stream");
result.Content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment")
FileName = "Data.xls"
return result;
catch (Exception ex)
m_logger.ErrorException("Exception exporting as excel file: ", ex);
return Request.CreateResponse(HttpStatusCode.InternalServerError);

Here is the coffeescript/javascript jquery ajax call from a button click in the interface.

url: route
dataType: 'json'
type: 'GET'
success: successCallback
error: errorCallback

Now that I think about it perhaps the dataType is wrong and shouldn't be json...

Answer Source

I had to make a couple of small changes to get this to work

First: Change the method to a post


Second: Change from using the jQuery ajax lib to use a hidden form, here's my service function for doing the hidden form and submitting it.

exportExcel: (successCallback) =>
    if $('#hidden-excel-form').length < 1
            method: 'POST',
            id: 'hidden-excel-form',
            action: 'api/tools/exportXls'

    $('#hidden-excel-form').bind("submit", successCallback)

Hopefully there's a better way to do this but for the time being it's working and downloading the excel file nicely.

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