Bind MLeader to an entity

[Anonymous]

Hi all,

I have a method DrawMLeaderLine(Database db, Transaction tr, Point3d point, string text) that draws me a MLeader line to the given point with the given text as annotation. The MLeader line points to the midpoint of a Line entity. What I need is a binding between the Line midpoint and the MLeader line, so when I move or resize the Line, the MLeader line should follow! I already tried to solve that, using constraints, but it doesn't work for Leaders.

This is my code...

public static MLeader DrawMLeaderLine(Database db, Transaction tr, Point3d point, string text)
        {
            Point3d mTextLocation = point + new Vector3d(5, 5, 0);

            BlockTableRecord btr = tr.GetObject(db.CurrentSpaceId, OpenMode.ForWrite) as BlockTableRecord;

            MText mText = new MText();
            mText.SetDatabaseDefaults();
            mText.SetContentsRtf(text);
            mText.Location = mTextLocation;

            MLeader mLeader = new MLeader();
            mLeader.SetDatabaseDefaults();
            mLeader.ArrowSize = 1.0d;
            mLeader.LandingGap = 0.5d;
            mLeader.DoglegLength = 1.0d;
            
            mLeader.ContentType = ContentType.MTextContent;
            mLeader.MText = mText;

            
            int idx = mLeader.AddLeaderLine(point);
            //mLeader.AddFirstVertex(idx, point + new Vector3d(2, 2, 0));
            
            btr.AppendEntity(mLeader);
            tr.AddNewlyCreatedDBObject(mLeader, true);

            return mLeader;
        }

will be called from a different class...

            Line line = DrawingUtil.DrawLine(doc.Database, tr, closestPoints.Item1, closestPoints.Item2);
 
            //Get midpoint of line
            double midPointX = (line.EndPoint.X + line.StartPoint.X) / 2.0d;
            double midPointY = (line.EndPoint.Y + line.StartPoint.Y) / 2.0d;
            Point3d midPointOfLine = new Point3d(midPointX, midPointY, 0);
 
            //Draw the leaderline
            MLeader leaderLine = DrawingUtil.DrawMLeaderLine(doc.Database, tr, midPointOfLine, "Connection");

Can anyone tell me, how I can "bind", "connect", "attach" (or whatever) the leaderline to the midpoint of the line?

Thanks for your replies...

Sebastian.

[BlackBox_]

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@Anonymous wrote:

What I need is a binding between the Line midpoint and the MLeader line, so when I move or resize the Line, the MLeader line should follow! 

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This may be helpful:

Anchoring AutoCAD entities to each other using .NET

[Anonymous]

Thanks for the link. But what I am looking for is more an AutoCAD feature. With the solution presented in the link, I have to listen to Move Commands and then recalculate the Anchoring. But then I have problems with copy/paste and reloading the file, etc.

When I create a MultiLeader manually in AutoCAD, there is a binding or anchoring by default. If I move the entity, the MultiLeader Line will follow. Which mechanism is used here? When I create it programmatically, this anchoring doesn't happen.