Uninstall VB6 causes error message: You do not have a license to use this control

I was running out of disk space on one of my machines, so I used my TreeMap program to see where I could delete files to save space.

I saw that I still had VB6 on the machine, and I didn’t need it on that machine any more, so I uninstalled it.

It's amazing how little disk space VB6 occupied, compared to VB.Net! I remember when FoxPro came on floppy disks, and Turbo Pascal came on a single (360k ?) floppy disk!

The next year (actually only several days later <g>), I tried running my trusty picture viewer which allows me to query and show my pictures and movies to show them or thumbnails. I received an error message: "You do not have a license to use this control".

I thought that it must have been the movie player ActiveX control that was giving me the problem.

I started Visual Studio and attached to the process, and found that the error occurred when MSCOMCTL.OCX was being loaded. That triggered a memory that I had removed VB6 a while ago. I think the MSCommon controls, such as the TreeView, ListView, Slider, etc originated from VB5, and Visual FoxPro and other products repackage them.

Upon further debugging, I found that it was actually the Slider control (which allows me to slide through almost 30,000 pictures/movies) that was giving the error.

            thisform.AddObject("oSlider","cSlider")

            WITH thisform.oSlider

                  .left=350

                  .width = 350

                  .visible=1

                  .min=1

                  .borderstyle=1

                  .largechange=1

            ENDWITH

DEFINE CLASS cSlider as olecontrol

      oleclass="mscomctllib.slider.2"

      PROCEDURE keypress(p1)

            thisform.keypress(p1)

      PROCEDURE change

            thisform.txtNum.value=this.value

            thisform.txtNum.valid

ENDDEFINE

I just needed to find what registry keys needed to be added back, so the application would work again. I found this link, which worked perfectly:

You receive an error message "You do not have a license to use this control" when you use Visual Basic 6.0 controls in Visual Studio 2005 or in Visual Studio .NET

see also

Microsoft Visual Basic 6.0 Common Controls