Deleting a client file after TransmitFile back to client

I'm trying to write a webpage that processes a clients file and then returns the file to the client.
When the file processing is completed a completion message is output to the clients browser and a
button is provided for the client to request the processed file.

The following sub sends the file back to the client:

Protected Sub Button1_Click(sender As Object, e As System.EventArgs) Handles ButtonSendClientFile.Click

        Dim attachName As String = "attachment; filename= " & Label1Copyname.Text
        Dim appPath As String = Request.PhysicalApplicationPath
        Dim saveDir As String = "ReturnToClientFiles\"
        Dim fileName As String = Label1Copyname.Text ' Get the name of the file to upload.
        Dim savePath As String = appPath + saveDir + fileName

        Response.ContentType = "text/plain"
        Response.AppendHeader("Content-Disposition", attachName)
        Response.TransmitFile(savePath)
        Response.End()
    End Sub

The next thing I need to do is remove the clients file from my server folder "ReturnToClientFiles"
If I add the line:

My.Computer.FileSystem.DeleteFile(savePath)

nothing happens, and wherever I place it - no result (except errors).

How do I achieve wiping the file after sending to client on a single button click event?

Re: Deleting a client file after TransmitFile back to client

Try this:

Response.TransmitFile(savePath);
Response.Flush();
File.Delete(savePath);
Response.End();