Question

I have a MS SQL view that I want to make available as a CSV download in my ASPNET Web Forms app. I am using Entity Framework for other views and tables in the project. What’s the best way to enable this download?

I could add a LinkButton whose click handler iterates over the view, writes its CSV form to the disk, and then serves that file. However, I’d prefer not to write to the disk if it can be avoided, and that involves iteration code that may be avoided with some other solution.

Answer 1

You could iterate over the dataset, but instead of creating the CSV file on your server simply return it through the HTTP response. The following function should do the trick.

Public Shared Sub ExportTextFile(ByVal response As System.Web.HttpResponse, ByVal text As String, ByVal fileName As String)

    response.Clear()
    response.AddHeader("content-disposition", String.Format("attachment;filename={0}", fileName))
    response.Charset = ""
    response.Cache.SetCacheability(HttpCacheability.NoCache)
    response.ContentType = "application/vnd.text"

    Dim stringWrite As New System.IO.StringWriter
    Dim htmlWrite = New HtmlTextWriter(stringWrite)
    response.Write(text.ToString)
    response.End()

End Sub