Accessing CommandBarButton.Picture property the late bound way

Question

I try to read the information of Microsoft Access (Office) CommandBars contained in an *.mdb. I could use Microsoft.Office.Interop.Access for this; however, these PIA assemblies are tied to specific Office versions. Therefore, to be version independent, I do it the late-bound way through C#'s dynamic type. I.e., I have no references to Microsoft Office specific assemblies. The price for this is that the access to the command bars is now weakly typed.

This approach works well, except when I try to access the custom button images. This is a condensed version of my real code to illustrate the problem:

dynamic access =  Activator.CreateInstance(Type.GetTypeFromProgID("Access.Application", true));
// Starts an Access XP (2002) process in my case, but could be any version.

foreach (dynamic commandBar in access.CommandBars) {
    if (!commandBar.BuiltIn) { // Only my menus and toolbars.
        foreach (dynamic control in commandBar.Controls) {
            if (control.Type == (int)MsoControlType.msoControlButton && !control.BuiltInFace) {
                string caption = control.Caption; // Works.
                stdole.IPictureDisp picture = control.Picture; // <==== Throws exception! ====
                // ...
            }
        }
    }
}

Calling the getter of the CommandBarButton.Picture property throws this exception:

Catastrophic failure (Exception from HRESULT: 0x8000FFFF (E_UNEXPECTED))

at System.Runtime.InteropServices.Marshal.ThrowExceptionForHRInternal(Int32 errorCode, IntPtr errorInfo) at System.Dynamic.ComRuntimeHelpers.CheckThrowException(Int32 hresult, ExcepInfo& excepInfo, UInt32 argErr, String message)
at System.Dynamic.UpdateDelegates.UpdateAndExecute1[T0,TRet](CallSite site, T0 arg0)
at System.Dynamic.UpdateDelegates.UpdateAndExecute1[T0,TRet](CallSite site, T0 arg0)
at MyApplication.MyMethod in MyApplication.cs:line 64

How can I get the picture avoiding this exception?

Note, this question is not about converting the IPictureDisp object to a System.Drawing.Image object. I already have a solution for this. Also, it makes no difference whether picture is typed as object, dynamic, or IPictureDisp. The property does exist, otherwise I would get the exception 'System.__ComObject' does not contain a definition for 'Picture'.

It is a .NET Framework 4.0 Windows Forms project compiled for x86 (32-bit).

Edit: Switching to Primary Interop Assemblies (PIA) allows strong typing, but does not solve the problem. The exception persists.

Meanwhile I have read more about PIAs. Since .NET Framework 4.0 you can tweak the properties of the assembly reference to make them version independent. Right click on References / Microsoft.Office.Interop.Access and

Set Embed Interop Types to True.
Set Specific Version to False.

Do this for References / office as well. Therefore I will be switching to PIAs instead of using dynamic.

"Dumb question": does the command bar control actually have a picture? Since the code is looping all the controls I just have to ask... And which version of Access is actually involved, here? A very quick look at the CommandBars.Control object (2010) doesn't reveal a Picture property, not even as a hidden member. A CommandBarButton, however, does have such a property. I think you need to determine the type and then cast to an object of the proper type. — Cindy Meister
– Cindy Meister, Commented Jan 28, 2020 at 17:31
The test control.Type == (int)MsoControlType.msoControlButton ensures that we have a CommandBarButton with such a property. I cannot test the type directly as it shows as System.__ComObject in the debugger. (And of course the real types are not available, since I have not referenced any Office libraries or PIA assemblies.) — Olivier Jacot-Descombes
– Olivier Jacot-Descombes, Commented Jan 28, 2020 at 17:47
If a property does not exist, the exception 'System.__ComObject' does not contain a definition for 'NonExistentProperty' is thrown. — Olivier Jacot-Descombes
– Olivier Jacot-Descombes, Commented Jan 28, 2020 at 17:53
I'm not arguing that it finds a control of that type. I'm saying you need to create a specific object of that type and assign the control to it with a cast so that you have an object that actually has a Picture property. VBA might make the conceptual leap (although I wouldn't count on it in this case - I seem to remember it didn't work, but it's been more than 10 years), C# in my experience isn't that flexible. Something along the lines of: Office.CommandBarButton cbb = (Office.CommandBarButton) control; — Cindy Meister
– Cindy Meister, Commented Jan 28, 2020 at 17:53
Note: VBA can do it, after a quick test. You might try PInvoke, instead, if you really want to return on the more generic Control. — Cindy Meister
– Cindy Meister, Commented Jan 28, 2020 at 17:59

Dean Peterson · Accepted Answer · 2025-08-05 16:41:30Z

0

I have no idea if this would help, but have you tried calling control.get_Picture()? I've had to explicitly use getter and setter methods instead of the properties for styles sometimes.

answered Aug 5 at 16:41

Dean Peterson

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1 Comment

Olivier Jacot-Descombes Aug 6 at 15:12

Thank you for the answer. Meanwhile I have gone another route. CommandBarButton buttons have a CopyFace() method copying the picture to the clipboard. I used it like this: Clipboard.Clear(); button.CopyFace(); if (Clipboard.ContainsImage()) { using Image image = Clipboard.GetImage(); .... I would prefer to get the image directly, but the clipboard solution also has the advantage that I don't have to convert a IPictureDisp object to a System.Drawing.Image.

Olivier Jacot-Descombes · Accepted Answer · 2025-08-06 15:33:49Z

It's been a few years since I published this question. But, since there is still interest in this question, I would like to present my solution here.

I have gone another route. CommandBarButton objects have a CopyFace() method copying the picture to the clipboard. I used it like this:

private Image Extract(CommandBarButton button, out string imageName)
{
    // The clipboard is not very reliable, so let's try several times.
    for (int tries = 0; tries < 10; tries++) {
        try {
            Clipboard.Clear();
            button.CopyFace();
            if (Clipboard.ContainsImage()) {
                using Image image = Clipboard.GetImage();
                if (image is not null) {
                    // Then I do some processing specific to my application
                    // using methods not shown here.
                    Image maskedImage = MakeTransparentContours(image);
                    if (!IsEmptyImage(maskedImage)) {
                        imageName = UniqueImageName(maskedImage);
                        return maskedImage;
                    }
                }
            } else {
                break;
            }
        } catch {
        }
        Thread.Sleep(100);  // Today I would probably do an async call.
    }
    imageName = null;
    return null;
}

When I see this old code, I see things I could have done differently, like using a TryExtract approach or returning the image and its name in a value tuple, use nullable reference types and what not...

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