topic Re: Getting the real COM class name in ArcObjects SDK Questions

Getting the real COM class name

JensHaffner — Wed, 18 Jul 2012 06:15:48 GMT

This problem really puzzles me...
I???d like to get the ArcObjects CoClass name behind the interface pointer, which I have.
If I???ve got an IFeature pointer, I???d like to know whether it???s in fact a Feature object or perhaps a ComplexEdgeFeature or something else.
No matter what I try, I don???t get the right name???

Re: Getting the real COM class name

KenBuja — Sat, 11 Dec 2021 09:09:22 GMT

Have you tried something like this (in VB.NET)

If TypeOf IFeature Is IComplexEdgeFeature Then
  
End If

Re: Getting the real COM class name

NeilClemmons — Sat, 11 Dec 2021 09:09:25 GMT

As Ken mentioned you can usually use TypeOf and test for a particular interface that will identify the underlying class. In .NET you can also use the GetType method and check the FullName property. This will give you the fully qualified class name.

Dim layer As IFeatureLayer = New FeatureLayer
                Dim s As String = layer.GetType.FullName

Re: Getting the real COM class name

JensHaffner — Sat, 11 Dec 2021 09:09:28 GMT

Ken, you are absolutely right, it is possible to check it this way:

If TypeOf IFeature Is IComplexEdgeFeature Then
End If

But I've learned, that in some cases it's difficult to pick an interface that is unique for a particular COM class.

Re: Getting the real COM class name

JensHaffner — Sat, 11 Dec 2021 09:09:30 GMT

Neil, perhaps I'm doing somthing wrong here, cause I've tried this:

IWorkspace pWorkspace = EsriDatabase.FileGdbWorkspaceFromPath("WhatEver.gdb");
Console.WriteLine(pWorkspace.GetType().FullName);

This code outputs "System.__ComObject" no matter which interface or class I use.

Re: Getting the real COM class name

sapnas — Sat, 11 Dec 2021 09:09:33 GMT

its a little tricky to get the type of com object. you may have to iterate through all the types and compare the object pointer with array of pointers returned by the com object. Below is the code to accomplish this. Hope this helps

 IntPtr iunkwn = Marshal.GetIUnknownForObject(pWorkspace);
            // enum all the types defined in the interop assembly
            System.Reflection.Assembly objAssembly =
            System.Reflection.Assembly.GetAssembly(typeof(IWorkspace));
            Type[] objTypes = objAssembly.GetTypes();
            // find the first implemented interop type
            foreach (Type currType in objTypes)
            {
                // get the iid of the current type
                Guid iid = currType.GUID;
                if (!currType.IsInterface || iid == Guid.Empty)
                {
                    // com interop type must be an interface with valid iid
                    continue;
                }
                // query supportability of current interface on object
                IntPtr ipointer = IntPtr.Zero;
                Marshal.QueryInterface(iunkwn, ref iid, out ipointer);
                if (ipointer != IntPtr.Zero)
                {
                    string str =currType.FullName;
                }
            }