How to find the name of the mate entity in an assembly

Question

How can I find the name of a mate entity of a component in an assembly?

That is, if a component is used twice in an assembly and has two coincident mates using the same face (of said component) with another component, can I extract a name that is the same for both mates? e.g. if there are two cubes C1 and C2 and a side of each cube has a mate with the other. Can we get a name of the mate, like C1:Ida and C2:Idb which will identify the side of the cube?

There was a similar question given here :https://forum.solidworks.com/thread/59399 and the suggested solution provided was

MateEntity2::Reference->MateReference::Name
MateEntity2::Reference→MateReference::ReferenceEntity2→ModelDoc2::GetEntityName

I have been unable to find the correct sequence of calls to get this.

Also, using examples given in the Solidworks API, the example, https://help.solidworks.com/2021/English/api/sldworksapi/Get_Mate_Reference_Properties_Example_Csharp.htm, seems to show that we want a MateReference but I have been unable to cast correctly from a MateEntity.Reference to any usable type.

Some code below provides a reproducible example (in solidworks 21) with many failed attempts to cast from a MateEntity.Reference to another type. Thanks for any pointers.

using SolidWorks.Interop.sldworks;
using SolidWorks.Interop.swconst;
using System.Diagnostics;

namespace SWquestion
{
    class Program
    {
        static void Main(string[] args)
        {
            // set up
            ModelDoc2 swModel = default;
            Mate2 swMate = default(Mate2);
            Feature swFeat = default;
            Feature swMateFeat = null;
            Feature swSubFeat = default;
            MateEntity2 swMateEnt = default;

            string fileName = null;
            int errors = 0;
            int warnings = 0;

            // Start SW
            SldWorks.SldWorks swApp;
            swApp = new SldWorks.SldWorks
            {
                Visible = false
            };

            //Open the assembly document :
            fileName = @"C:\Users\Public\Documents\SOLIDWORKS\SOLIDWORKS 2021\samples\tutorial\api\wrench.sldasm";
            swModel = (ModelDoc2)swApp.OpenDoc6(fileName, (int)swDocumentTypes_e.swDocASSEMBLY, (int)swOpenDocOptions_e.swOpenDocOptions_Silent, "", ref errors, ref warnings);

            // Iterates through the FeatureManager design tree to find Mates
            swFeat = (Feature)swModel.FirstFeature();
            while ((swFeat != null))
            {
                if ("MateGroup" == swFeat.GetTypeName())
                {
                    swMateFeat = (Feature)swFeat;
                    break;
                }
                swFeat = (Feature)swFeat.GetNextFeature();
            }

            // grab first mate entity : can get parameters etc
            swSubFeat = (Feature)swMateFeat.GetFirstSubFeature();
            swMate = (Mate2)swSubFeat.GetSpecificFeature2();
            swMateEnt = swMate.MateEntity(0);

            // Mate entity reference has property value 'Mate reference'
            // But how is this object used?
            // https://help.solidworks.com/2021/English/api/sldworksapi/SolidWorks.Interop.sldworks~SolidWorks.Interop.sldworks.IMateEntity2~Reference.html
            object swRef = swMateEnt.Reference;
            Debug.Print("swRef: " + swRef.GetType()); // com_object

            // How to get the name??
            // perhaps https://help.solidworks.com/2021/English/api/sldworksapi/SolidWorks.Interop.sldworks~SolidWorks.Interop.sldworks.IMateReference_members.html
            // Tried various casts, all with error
            IMateReference ms = (IMateReference)swMateEnt.Reference; // error: Unable to cast COM object of type 'System.__ComObject' to interface type 'SolidWorks.Interop.sldworks.IMateReference'.
            // MateReference ms = (MateReference)swMateEnt.Reference; // com error  on cast
            // MateEntity2 ms = (MateEntity2)swMateEnt.Reference; // com error  on cast
            // ModelDoc2 ms = (ModelDoc2)swMateEnt.Reference; // com error  on cast
            // string[] ms = (string[])swMateEnt.Reference; // com error on cast from ComObject to string[]
            // double[] ms = (double[]) swMateEnt.Reference; // com error on cast

            // Try a different route from link below
            // https://help.solidworks.com/2021/English/api/sldworksapi/Get_Mate_Reference_Properties_Example_CSharp.htm
            //ModelDocExtension swModelDocExt = (ModelDocExtension)swModel.Extension;
            //SelectionMgr swSelMgr = (SelectionMgr)swModel.SelectionManager;
            //bool boolstatus = false;
            //string mtName = swSubFeat.Name;
            //boolstatus = swModelDocExt.SelectByID2(mtName, "MATE", 0, 0, 0, false, 0, null, 0);
            //Feature swFeature = (Feature)swSelMgr.GetSelectedObject6(1, -1);
            //MateReference swMateReference = (MateReference)swFeature.GetSpecificFeature2(); // error: 'Unable to cast COM object of type 'System.__ComObject' to interface type 'SolidWorks.Interop.sldworks.MateReference'.
        }
    }
}

(This is cross-posted here without response)

Answer 1

I am not an experienced user, so not sure if this helps. The API Help document (https://help.solidworks.com/2022/english/api/sldworksapi/SolidWorks.Interop.sldworks~SolidWorks.Interop.sldworks.IMateEntity2~Reference.html?verRedirect=1) wrongly states that (at list since version 2010) the return value of MateEntity2.Reference is of type MateReference. In fact it is of type Entity. There are a couple of example that use Entity = MateEntity2.Reference