Adding code generated entities to a selection set

[lambwill]

I am slowly trying to get to grips with VB.NET, after a good few years of messing around with VBA.
I’m currently writing some code to try to improve CAD’s MEASURE command, but I’ve hit a bit of a stumbling block.
I have my command working to the extent that it will place blocks at regular intervals along a polyline, but I would like to add the generated blocks to a selection set, so you can use “previous” to select them like you can with CAD’s MEASURE command.

e.g. If I used the MEASURE command in CAD to place blocks along a polyline, then wanted to explode the blocks directly after, I could just use:
EXPLODE <ENTER>
P <ENTER>
to explode the previous selection set, but my code never adds the blocks to a selection set – so you have to select them manually.

To add an entity to a selection set in VBA you would do something like this (excuse the pseudo-code):

Dim Ent as Entity
Ent = (whatever)

Dim SS as SelectionSet
SS.Add(Ent)

VB.NET doesn’t seem to have an Add method for selection sets though, as far as I can gather you can only get them by using SelectAll & a dxf code filter – which would just grab all instances of the block, unless I went down the route of adding a temporary unique layer for them, or something along those lines.

Am I missing something obvious here?

Thanks in advance,
Will

[fixo]

For somebody else to whom this would be interesting as well

Take a look at SetImpliedSelection method of document Editor

Here is Q&D example:
(slightly tested on A2009)

       static public void AddItemsExm()
        {
            Editor ed = Application.DocumentManager.MdiActiveDocument.Edit​or;
 
            Database db = HostApplicationServices.WorkingDatabase;
 
            using (Transaction tr = db.TransactionManager.StartTransaction())
            {
                try
                {
                    BlockTableRecord btr = tr.GetObject(db.CurrentSpaceId, OpenMode.ForWrite) as BlockTableRecord;
 
                    SelectionFilter sf = new SelectionFilter(
 
                     new TypedValue[] { new TypedValue(0, "LINE") });
 
                    PromptSelectionOptions pso = new PromptSelectionOptions();
 
                    pso.MessageForAdding = "\nSelect lines only >>";
 
                    pso.SingleOnly = false;
 
                    PromptSelectionResult res = ed.GetSelection(pso, sf);
 
                    if (res.Status != PromptStatus.OK)
 
                        return;
 
                    SelectionSet main = res.Value;
 
                    ObjectId[] oids = main.GetObjectIds();
 
                    ed.WriteMessage("\nSelected {0} objects", oids.Length);
 
                    Line ln = new Line(new Point3d(0, 0, 0), new Point3d(0, 1000, 0));//dummy line for test
 
 
                    btr.AppendEntity(ln);
 
                    tr.AddNewlyCreatedDBObject(ln, true);
 
                    int cnt = oids.Length;
 
                    Array.Resize(ref oids, cnt + 1);
 
                    oids[cnt] = ln.ObjectId;
 
                    SelectionSet newset = SelectionSet.FromObjectIds(oids);
 
                    main = null;
 
                    ed.SetImpliedSelection(newset);
 
                    ed.WriteMessage("\nAfter adding line: {0} objects", newset.GetObjectIds().Length);
 
                    foreach (SelectedObject obj in newset)
                    {
                        Entity en = (Entity)tr.GetObject(obj.ObjectId, OpenMode.ForRead);
 
                        en.UpgradeOpen();
 
                        en.ColorIndex = 1;
 
                        en.DowngradeOpen();
 
                    }
 
                    tr.Commit();
 
                }
 
                catch (Autodesk.AutoCAD.Runtime.Exception ex)
                {
                    Autodesk.AutoCAD.ApplicationServices.Application.S​howAlertDialog(ex.Message);
                }
            }
        }

~'J'~

[lambwill]

Thanks Fixo,
That more or less fixed my problem.
I just needed to use "document.SendStringToExecute" to execute the SELECT command after SetImpliedSelection, in order to de-select the items and make them available as the previous selection set.
Here's the (abridged) code I used in the end:

'####################################################

<CommandMethod("MB", CommandFlags.Redraw)> _
Public Sub NewMeasure()
     Dim myDWG As ApplicationServices.Document =  ApplicationServices.Application.DocumentManager.MdiActiveDocument
     Dim myEd As EditorInput.Editor = myDWG.Editor

		
     Dim MeasureObjects As DBObjectcollection = CreateObjects 


     If MeasureObjects.Count > 0 Then
         Dim SelSet As SelectionSet = AddToSelectionSet(MeasureObjects)
         myEd.SetImpliedSelection(SelSet)
         myDWG.SendStringToExecute("SELECT ", False, False, False)
     End If
End Sub

Function AddToSelectionSet(ByVal Objects As DBObjectCollection) As SelectionSet
     Dim ObjectIDs(0 To (Objects.Count - 1)) As ObjectId
     Dim ThisObjectID As ObjectId
     Dim Obj As DBObject
     For i As Integer = 0 To (Objects.Count - 1)
         Obj = Objects(i)
         ThisObjectID = Obj.ObjectId
         ObjectIDs(i) = ThisObjectID
     Next
     Dim SelSet As SelectionSet = SelectionSet.FromObjectIds(ObjectIDs)
     Return SelSet
End Function

'####################################################

Thanks,
Will

[fixo]

Thanks Fixo,
That more or less fixed my problem.

Will

You're welcome, Will
Cheers
Oleg

~'J'~