Calling an ArcMap extension(add-in) method from another ArcMap extension(add-in)

vsevgu — Tue, 16 Jan 2024 14:32:59 GMT

I have a third-party ArcMap extension (codes not available) is SomeException.
This extension implements the IExtension, IExtensionConfig, IPersistVariant and ISomeInterface interfaces
I'm calling SomeException methods from another ArcMap extension.

On a Windows 10 machine running ArcGis 10.5, the ISomeInterface methods are available from my extension and (SomeException is ISomeInterface) = true.
On a Windows 8 machine running ArcGis 10.2, ISomeInterface methods are not available from my extension and (SomeException is ISomeInterface) = false.
The IExtension, IExtensionConfig, IPersistVariant interfaces are always available.

What could be the problem?

Perhaps ISomeInterface is not a COM interface.
I don't know whether the SomeException extension class has the ComVisible(true) attribute or not.

Is there any way to make all interfaces of the SomeException extension available at the OS level?

On a Windows 8 machine running ArcGis 10.2, the ISomeInterface interface can be accessed by declaring the COM extension object as dynamic.
For example:

var extClass = new UIDClass(); extClass.Value = "{XXXXX-XXX...}"; dynamic someExt = _application.FindExtensionByCLSID( extClass); someExt.SomeMethod(); //method of ISomeInterface

If SomeMethod has no parameters, then the call occurs correctly.
If SomeMethod has a class among its parameters, an error occurs.
For example, such a call to the method

someExt.SomeMethod_2(someClass); //method 2 of ISomeInterface

is the following error:

System.InvalidCastException: Failed to cast object type 'System.__ComObject' to type 'someClass'. in System.Runtime.InteropServices.Marshal.ThrowExceptionForHRInternal(Int32 errorCode, IntPtr errorInfo) in System.Dynamic.ComRuntimeHelpers.CheckThrowException(Int32 hresult, ExcepInfo& excepInfo, UInt32 argErr, String message) in CallSite.Target(Closure , CallSite , ComObject , JOB ) in System.Dynamic.UpdateDelegates.UpdateAndExecute2[T0,T1,TRet](CallSite site, T0 arg0, T1 arg1) in CallSite.Target(Closure , CallSite , Object , JOB ) in System.Dynamic.UpdateDelegates.UpdateAndExecuteVoid2[T0,T1](CallSite site, T0 arg0, T1 arg1)

How can I call SomeMethod_2 correctly?

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Calling an ArcMap extension(add-in) method from another ArcMap extension(add-in)