Forms :: TreeView - Changing Download Link For Button

I am working with buttons I have A treeview that when you click on a node it changes the text in textboxes and I need it to change the command the button does. So when a user clicks a node it changes text in 3 text boxes and changes the download link for the button. As you can see from the code all works fine but I need to use a button to download stuff and I dont know how the download code is

My.Computer.Network.DownloadFile _
("[URL]", _
cookiepack)
MsgBox("done")

That's what I need the button to do
Private Sub TreeView1_NodeMouseClick(ByVal sender As System.Object, ByVal e As System.Windows.Forms.TreeNodeMouseClickEventArgs) Handles TreeView1.NodeMouseClick
Dim filePath As String
filePath = Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData)
[Code] .....