Question

I have a web browser I’m using in my VB.net form to which I drag *.CTB files. At present I can drag any file type into the browser can I limit this to CTB file extensions only and if the user ties to drag in any other extension that a message box appears quoting that the file must be ctb extension?

Answer 1

The WebBrowser control is handling the drag/drop functionality so you might not be able to (easily) intercept that. Instead, you could handle the Navigating method and cancel the navigation if the file type is incorrect. (You might want to do a more robust check for the extension).

Private Sub WebBrowser_Navigating(sender As Object, e As WebBrowserNavigatingEventArgs)
    'get file extension
    Dim ext As String = e.Url.ToString.Substring(e.Url.ToString.Length - 3)
    If ext <> "CTB" Then
        e.Cancel = True
        MessageBox.Show("Only CTB files are allowed")
    End If
End Sub