Disabling single line copy in Visual Studio

If you aren't willing to customize the keyboard settings, then Ctrl+C will always be Edit.Copy, which will copy the current line if nothing is selected. If you aren't willing to use the tools VS provides to customize the interface, then you can't do it.

However, the following works: Assign this macro to Ctrl+C:

Sub CopyOnlyIfSelection()
    Dim s As String = DTE.ActiveDocument.Selection.Text
    Dim n As Integer = Len(s)
    If n > 0 Then
        DTE.ActiveDocument.Selection.Copy()
    End If
End Sub

The real problem you probably experience is that you go to paste, with CTRL+V. And you accidentally type CTRL+C, and end up overwriting the stuff that's on your clipboard. You can't disable this as far as I know, however, the work around for this, is that you can press CTRL+SHIFT+V multiple times to go back up the stack of things you have copied in visual studio. Not only does this allow you to recover what you originally copied, but you'll also find that CTRL+SHIFT+V very useful in a lot of other situations.