ProgId/Guid for Custom Task Pane Helper

[p0n3]

Problem
There is no easy way to set ProgId/Guid for a Custom Task Pane Helper component (ExcelCustomTaskPaneAddIn), which might cause a problem in restricted environments.

Details
ExcelCustomTaskPaneAddIn is an internal class and the instance is being created in the GetCTPFactory method inside CustomTaskPaneFactory:

// Register and create addin
_addin = new ExcelCustomTaskPaneAddIn { DnaLibrary = DnaLibrary.CurrentLibrary };
ExcelComAddInHelper.LoadComAddIn(_addin);

LoadComAddIn checks if the class has ProgId/Guid attribute, and if not it generates id based on the xll path. It works well if you e.g. extend ExcelRibbon class, but ExcelCustomTaskPaneAddIn is an internal class, so you cannot do much with it, therefore it always uses generated id.

[govert]

That sounds reasonable. Do you mean you need to register the control and CTP add-in in the registry yourself, or at another time?

The ExcelCustomTaskPane code is quite small with two classes and mostly dealing with the on-demand COM registration.
So you could just make a copy of the code from https://github.com/Excel-DNA/ExcelDna/blob/master/Source/ExcelDna.Integration/ExcelCustomTaskPane.cs in your own add-in project, and rename the types to MyCustomTaskPaneFactory' and MyCustomTaskPaneAddIn. The only coupling I see with the rest of Excel-DNA is the fact that the add-in class derives from ExcelAddIn`, so you need that. I might be missing something, but it seems worth a try.

[p0n3]

Do you mean you need to register the control and CTP add-in in the registry yourself, or at another time?

I just need to have a fixed ProgId to be able to whitelist it in a whole organization. So from my perspective it might be even hardcoded in the library ([ProgId("ExcelDna.CTP")] or smth like that)

you could just make a copy of the code

I tried, but the problem is there are bunch of internal classes/interfaces inside this file that cannot be accessed from another assembly like: ICustomTaskPaneConsumer, ProgIdRegistration, ClsIdRegistration, SingletonClassFactoryRegistration which uses another internal method - RegisterClassFactory and so on and so on.

[govert]

OK - I see there is some more plumbing behind it, including the class factory provided by Excel-DNA.

[theboyknowsclass]

any word on this?

[govert]

We should get back to this, also in the context of this discussion https://groups.google.com/g/exceldna/c/RtDONHNDqsw

[govert]

@Sergey-Vlasov - it would be good to make a pass through the various COM registration aspects, to check that we support some way of fixing stable guids and progids wherever they are used. Many users need to have these pre-registered, or set up security exceptions for fixed progids and guids, and we should be compatible with this requirement.

[Sergey-Vlasov]

To create a restricted environment, I enabled the "Block all unmanaged add-ins" policy:

Now trying to load ExcelDna.Test\bin\Debug\net6.0-windows\ExcelDna.Test-AddIn.xll:

ComAddIn [Error] The Ribbon/COM add-in helper required by add-in Test .NET 6 add-in could not be registered.
This may be due to the helper add-in being disabled by Excel.
To repair, open Disabled items in the Options->Add-Ins page and re-enable target add-in, then restart Excel.
Error details: System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation.
---> System.Runtime.InteropServices.COMException (0x80004005): The add-in you have selected is disabled by your system administrator.
--- End of inner exception stack trace ---
at System.RuntimeType.InvokeDispMethod(String name, BindingFlags invokeAttr, Object target, Object[] args, Boolean[] byrefModifiers, Int32 culture, String[] namedParameters)
at System.RuntimeType.InvokeMember(String name, BindingFlags bindingFlags, Binder binder, Object target, Object[] providedArgs, ParameterModifier[] modifiers, CultureInfo culture, String[] namedParams)
at System.Type.InvokeMember(String name, BindingFlags invokeAttr, Binder binder, Object target, Object[] args, CultureInfo culture)
at ExcelDna.Integration.ComInterop.TypeAdapter.SetProperty(String name, Object value, Object comObject) in e:\programming\Govert\Excel-DNA\ExcelDna-ProgId\Source\ExcelDna.Integration\ComInterop\TypeAdapter.cs:line 46
at ExcelDna.Integration.ExcelComAddInHelper.LoadComAddIn(ExcelComAddIn addIn) in e:\programming\Govert\Excel-DNA\ExcelDna-ProgId\Source\ExcelDna.Integration\ComInterop\ExcelComAddInHelper.cs:line 133 : TargetInvocationException - Exception has been thrown by the target of an invocation.

[Sergey-Vlasov]

To resolve the ribbon loading error, generate and add ProgId/Guid to Source\ExcelDna.Test\RibbonController.cs:

[ComVisible(true)]
[ProgId("175c15e3-4dd8-49d0-94cf-f95800017594")]
[Guid("6242439e-ecc6-46eb-a666-edd3d93414a4")]
public class RibbonController : ExcelRibbon

And add the ProgId to the List of managed add-ins:

[Sergey-Vlasov]

Sample code to create a custom task pane:

internal class CustomPane
{
    public static void Show()
    {
        var myControl = new MyUserControl();
        var customPane = CustomTaskPaneFactory.CreateCustomTaskPane(myControl, nameof(myControl));

        customPane.Visible = true;
    }
}

public interface IMyUserControl { }

[ComVisible(true)]
[Guid("c5a18d1b-b798-49cf-9a3f-37a094905170")]
[ComDefaultInterface(typeof(IMyUserControl))]
public class MyUserControl : UserControl, IMyUserControl { }

When CustomPane.Show() is called from a command:

ComAddIn [Error] The Ribbon/COM add-in helper required by add-in Test .NET 6 add-in could not be registered.
This may be due to the helper add-in being disabled by Excel.
To repair, open Disabled items in the Options->Add-Ins page and re-enable target add-in, then restart Excel.
Error details: System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation.
---> System.Runtime.InteropServices.COMException (0x80004005): The add-in you have selected is disabled by your system administrator.
--- End of inner exception stack trace ---
at System.RuntimeType.InvokeDispMethod(String name, BindingFlags invokeAttr, Object target, Object[] args, Boolean[] byrefModifiers, Int32 culture, String[] namedParameters)
at System.RuntimeType.InvokeMember(String name, BindingFlags bindingFlags, Binder binder, Object target, Object[] providedArgs, ParameterModifier[] modifiers, CultureInfo culture, String[] namedParams)
at System.Type.InvokeMember(String name, BindingFlags invokeAttr, Binder binder, Object target, Object[] args, CultureInfo culture)
at ExcelDna.Integration.ComInterop.TypeAdapter.SetProperty(String name, Object value, Object comObject) in e:\programming\Govert\Excel-DNA\ExcelDna-ProgId\Source\ExcelDna.Integration\ComInterop\TypeAdapter.cs:line 46
at ExcelDna.Integration.ExcelComAddInHelper.LoadComAddIn(ExcelComAddIn addIn) in e:\programming\Govert\Excel-DNA\ExcelDna-ProgId\Source\ExcelDna.Integration\ComInterop\ExcelComAddInHelper.cs:line 133 : TargetInvocationException - Exception has been thrown by the target of an invocation.

[Sergey-Vlasov]

I've added stable ProgId/Guid for a Custom Task Pane Helper component (ExcelCustomTaskPaneAddIn).

To resolve the custom task pane creation error in a restricted environment, add ExcelDna.CustomTaskPaneAddIn to the List of managed add-ins: