Question

We’ve got a page in our asp.net web system that uses response.redirect to redirect the user directly to an excel file so it will download ‘automatically’ without the user having to to a right click / save as.

This works great – except for files over about 100k in IE7. Other browsers just download the large file fine, and IE works fine under that threshold, but at somewhere about 200k, IE just starts handing out ‘page cannot be displayed’ errors.

Obviously, we’d like the user to be able to download in IE as well – any ideas? Is there some kind of download size threshold thing I can override?

Answer 1

I prefer a different method for sending files. It works for me with all kinds of different types and sizes of files.

Instead of using Response.Redirect, allow the link to the file to do a postback where you modify the response, like so:

Public Shared Sub SendFileToBrowser(ByRef response As HttpResponse, ByVal filepath As String, Optional ByVal filename As String = '', Optional ByVal contentType As String = '', Optional ByVal disposition As String = '', Optional ByVal contentLength As String = '')     Dim ext As String = filepath.Substring(filepath.Length - 3, 3)      If String.IsNullOrEmpty(contentType) Then         If ext = 'pdf' Then             contentType = 'application/pdf'         Else             contentType = 'application/file'         End If     End If      If String.IsNullOrEmpty(disposition) Then         disposition = 'attachment'     End If      If String.IsNullOrEmpty(filename) Then         ''//Test for relative url path         Dim fileparts As String() = filepath.Split('/')         If fileparts.Length > 1 Then             filename = fileparts(fileparts.Length - 1)         Else             ''//Test for absolute file path             Dim fileparts2 As String() = filepath.Split('\')     ''//' SO: Fix syntax highlighting             If fileparts2.Length > 1 Then                 filename = fileparts2(fileparts2.Length - 1)             Else                 ''//Just give it a temp name                 filename = 'temp.' & ext             End If         End If     End If      response.Clear()      response.AddHeader('content-disposition', disposition & ';filename=' & filename)     If Not String.IsNullOrEmpty(contentLength) Then         response.AddHeader('Content-Length', contentLength)     End If      response.ContentType = contentType      response.Cache.SetCacheability(HttpCacheability.Public)              response.TransmitFile(filepath)     response.End() End Sub 

Note: Using ”’//’ for comments so that the syntax highlighter works properly. This still compiles properly as well.

This works for us in IE6 and IE7.