joining entities doesnt seem to do anything

[adrian_sieradzki]

Hello,

In .NET sdk for autocad I am trying to replicate _JOIN command. I have an entity[] which are all splines and would like to join it to as few splines/entities as possible.

entityArray.ForEach( x => x.JoinEntities(entityArray));
 

but not even single spline is joined to another spline. Surely I must be missing something because debugger doesnt throw any exceptions and executes normally. 

[adrian_sieradzki · Accepted solution]

Okay, figured this out but its quite weird

//THIS WORKS
                foreach (Entity entity in device.myEntities)
                {
                    entity.JoinEntities(device.myEntities.ToArray());
                    btr.AppendEntity(entity);
                    tr.AddNewlyCreatedDBObject(entity, true);

                }
//THIS DOESNT WORK
                device.myEntities.ForEach(x => x.JoinEntities(device.myEntities.ToArray()));
foreach (Entity entity in device.myEntities)
                {
                    btr.AppendEntity(entity);
                    tr.AddNewlyCreatedDBObject(entity, true);

                }

[_gile]

Hi,

Entity.JoinEntities method does not work this way. It have to be called on one instance of entity and requires as argument an array of entities.

Here's an example:

        [CommandMethod("TESTJOIN")]
        public static void TestJoin()
        {
            var doc = Application.DocumentManager.MdiActiveDocument;
            var db = doc.Database;
            var ed = doc.Editor;

            // Prompt the user to select the primary spline
            var entityOptions = new PromptEntityOptions("\nSelect primary spline: ");
            entityOptions.SetRejectMessage("\nMust be a spline.");
            entityOptions.AddAllowedClass(typeof(Spline), true);
            var entityResult = ed.GetEntity(entityOptions);
            if (entityResult.Status != PromptStatus.OK)
                return;

            // Prompt the user to select the spline to join to the first one.
            var filter = new SelectionFilter(new[]
            {
                new TypedValue(0, "SPLINE"),
                new TypedValue(-4, "<NOT"),
                new TypedValue(-4, "&"),
                new TypedValue(70, 1),
                new TypedValue(-4, "NOT>")
            });
            var selectionOptions = new PromptSelectionOptions();
            selectionOptions.MessageForAdding = "\nSelect the spline to join: ":
            var selection = ed.GetSelection(filter);
            if (selection.Status != PromptStatus.OK)
                return;

            using (var tr = db.TransactionManager.StartTransaction())
            {
                // Open the first spline
                var spline = (Spline)tr.GetObject(entityResult.ObjectId, OpenMode.ForWrite);

                // Create an array with the other splines
                var otherSplines = selection.Value
                    .GetObjectIds()
                    .Select(id => (Spline)tr.GetObject(id, OpenMode.ForWrite))
                    .ToArray();

                try
                {
                    // Join the selected splines to primary one
                    var indices = spline.JoinEntities(otherSplines);

                    // Erase the joined plines
                    foreach (int index in indices)
                    {
                        otherSplines[index].Erase();
                    }
                }
                catch(Autodesk.AutoCAD.Runtime.Exception ex) when (ex.ErrorStatus == ErrorStatus.NotApplicable)
                {
                    ed.WriteMessage("\nThe first spline does not join to any selected ones");
                }
                catch(System.Exception ex)
                {
                    ed.WriteMessage($"\n{ex.Message}");
                }
                tr.Commit();
            }
        }

[adrian_sieradzki]

Yes it does, see my answer above.
For some reason in only works if I call it inside the same loop as my 

tr.AddNewlyCreatedDBObject

There must be some object manipulating behaviour I am not aware of.

My last 3 days of playtime with AutoCAD has led me to believe the code-base must be incredible spaghetti.

If you are looking to re-write it with some modern framework such as blazor or tauri I can help you as part-time consultant.