I have a WinForm application. I also have created my own User Control for it. Everything worked fine. Until today that I received the error message when I try to add it back to my program (I never removed it. Visual Studio did).
Failed to load toolbox item #UserControlName. It will be removed from the toolbox.
I have it in my solution explorer but it vanishes from my toolbox after this error. I also receive the warning that says:
'#UserControlName' is never assigned to, and will always have its default value null.
And when I look at my designer code, that is true. But I haven't done anything with my designer code. My user control is defined there but not instantiated. How can I put it back?
Does it have anything to do with the fact that I changed my build platform from x32 to x64? If that is the case I will be surprised because the program was working fine after that change.
At times like these, you'll be forced to tinker with the designer code. As long as you don't make drastic changes in the designer code, you shouldn't break anything. To play it safe, re-instantiate the object where the other controls are instantiated (near the top of the page). The designer should fill in the blanks for properties and such.
This should also return the control to the toolbox.