Monodevelop warning "Could not generate code for widgets of type: xxxx"

Question

About 2 years ago I worked on a C# project, using MonoDevelop V1 and later V2 (beta release, compiled from source, what a mission) under Fedora. The project went dead. Now I am bringing it back to life, but I have changed my development platform to Debian (testing, i.e. squeeze), which has MonoDevelop V2.2.

I am mostly very pleased with the features of V2.2, but I have a nasty little problem. All the code compiles OK, but at the end of the compilation run I am left with lots of warnings as in the subject line. Obviously, as soon as I try and run the application, I get exceptions left, right and center when I open anything that uses these widgets.

The funny thing is that the library containing the widgets compiles just fine. But somehow these widgets (it's not all of them, only one or two) don't get exposed on the interface, and then subsequent dialogs or windows using them throw the above warning.

Has anybody had this problem? I have googled this and all that comes up is Michael Hutchinson throwing his hands in the air and saying "sorry, can't help here". I really need a fix for this, otherwise I will have to rewrite substantial chunks of code from scratch.

Answer 1

I would recommend trying MonoDevelop 2.4, but in any case here are some hints.

If you have an assembly which uses custom widgets implemented in the same assembly, you may be having a chicken-egg problem, since MonoDevelop needs the built assembly in order to find the custom widgets, but that's the assembly you are trying to build. This problem can be easily solved by building again the project after you get the warnings you reported. Beware, you have to build, not rebuild, since rebuild will delete the assembly and you'll hit the same problem again.

If you are not having the above problem, or if the solution doesn't work, the problem may be that the objects.xml file that contains the information about the exported widgets is not properly updated. You'll find that file in the project that implements the custom widgets, in a hidden gtk-gui folder. Open the file and check if the all the custom widgets are declared there. If a widget is missing, try opening the source code file of the widget and do a small change (e.g. a whitespace change) and then build the project again. MonoDevelop should be properly updating the file.

If you are still having trouble, please file a bug report.