返回HttpResponseMessage的控制器未正确设置内容类型

Question

I have the following code in a controller to return a stream which is an Excel File to download on the client side:

HttpResponseMessage response = new HttpResponseMessage(HttpStatusCode.OK);
MemoryStream memStream = ReportExporter.ExportReport(analystReport);

response.Content = new StreamContent(memStream);
response.Content.Headers.ContentType = new MediaTypeHeaderValue("application/octet-stream");
response.Content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment");
response.Content.Headers.ContentDisposition.FileName = saveAsFileName;

return response;

When I make the request on the client side it simply gives me back the wrapper of the response message:

StatusCode: 200, ReasonPhrase: 'OK', Version: 1.1, Content: System.Net.Http.StreamContent, Headers:
{
  Content-Type: application/octet-stream
  Content-Disposition: attachment; filename=.xlsx
}

I believe this maybe due to the headers coming back as text as this is what I see in Chrome:

Content-Type:text/html; charset=utf-8   

I can't work out what is happening here having tried various things.

Answer 1

Try this solution:

// Copy file to byte array
byte[] file = new byte[memStream.Length];
memStream.Read(file, 0, file.Length);

// Send file
Response.ContentType = "application/octet-stream";
Response.AddHeader("content-disposition", "inline;filename=" + saveAsFileName);
Response.Buffer = true;
Response.Clear();
Response.BinaryWrite(file);
Response.End();

// Return success
return new HttpStatusCodeResult(HttpStatusCode.OK);

Response is a Controller property, so you don't need to create any HttpResponseMessage object.

Answer 2

There are many ways to solve this, but I will show you mine. Instead of HttpResponseMessage you can just do FileStreamResult. And You dont need to instantiate HttpResponseMessage, its already part of the controller method. This is how I would start to try to fix your code. Remember to use FileStreamResult instead.

    public FileStreamResult DownloadExcel(???analystReport????)
    {
        MemoryStream memStream = ReportExporter.ExportReport(analystReport);

        return new FileStreamResult(memStream , "application/vnd.ms-excel", saveAsFileName);
    }