When activating OLEControl in my PowerBuilder application, toolbar items disappear

Question

I have created a COM Interop Control in C# to use in my PB application. If I add an ole control to my userobject and select my C# object in the painter, then an olecustomcontrol is created and everything works as expected. However, in order to use a 64-bit version of my object when building the project for a 64-bit platform (in PB Classic 12.6) I added an ole control but hit cancel when asked to select an object, so an olecontrol is created and I can use InsertClass to select my object at runtime. This is working for me but I have one issue: when the user clicks in my control, activating it, the toolbar icons on my MDI window disappear. From the research I have done, it sounds like PB may expect the ole object to provide the menus and toolbars, but my PB menu items are unaffected, it is just the toolbar. My control does contain a toolbar (the control is a rich text editor I created to workaround some shortcomings of the built in control) but I have also tried creating a new Interop Control with only a plain text box on it and got the same results. Actually I also tried using one of the Microsoft controls (Microsoft InkEdit Control) installed on my system, and again got the same results.

Does anyone know how I can fix this toolbar problem? (I'm at a loss, but I'm guessing it may be that I need to somehow tell PB to ignore OLE toolbars and/or tell my C# object not to advertise a toolbar.)

noseratio noseratio · Accepted Answer · 2015-11-04T22:16:43

Ah, that legacy code we have to support for decades...

The following would take some research and may not eventually solve the problem, but I'd give it a try. I'd implement a "proxy" COM object that'd serve as an extra layer between your .NET OLE control and its OLE container. Such object would be exposed as OLE control to the PB runtime, and as OLE Container to the .NET control, and forward the COM methods calls between the two. It'd be much easier to code this layer with C++/ATL, but it should be doable with bare C#, too.

Then I'd watch the calls made on IOleInPlaceFrame and IOleInPlaceUIWindow interfaces and block those which lead to the undesired toolbar behavior (if any). I'd also limit the set of OLE control interfaces exposed to the PB runtime to some bare minimum.

The implementation details of AxHost and Control classes might be helpful here, as well as the ATL library source code.

When activating OLEControl in my PowerBuilder application, toolbar items disappear

2 Answers