How to open PDF in Reader rather than download file

[Rhodo]

I've inherited a VB.net application that uses a button click to open PDF files stored on a server. I want the PDF to open in Adobe Reader, but the following code downloads the file instead. How can I open it in Reader?

...

Response.Buffer = False
Response.Clear()
Response.ClearContent()
Response.ClearHeaders()
Response.ContentType = "application/pdf"
Response.AddHeader("Content-disposition", "attachment; filename=" & name)
Response.TransmitFile("c:\12345.pdf")
Response.End()