How to create MLeader objects in .Net?

By Philippe Leefsma

 

Below are two samples that illustrates MLeader creation in C#:

The first creates a MLeader with a MText content:

 

[CommandMethod("netTextMLeader")]

public static void netTextMLeader()

{

    Document doc = Application.DocumentManager.MdiActiveDocument;

    Database db = doc.Database;

    Editor ed = doc.Editor;

 

    using (Transaction Tx = db.TransactionManager.StartTransaction())

    {

        BlockTable table = Tx.GetObject(

            db.BlockTableId,

            OpenMode.ForRead)

                as BlockTable;

 

        BlockTableRecord model = Tx.GetObject(

            table[BlockTableRecord.ModelSpace],

            OpenMode.ForWrite)

                as BlockTableRecord;

 

        MLeader leader = new MLeader();

        leader.SetDatabaseDefaults();

 

        leader.ContentType = ContentType.MTextContent;

 

        MText mText = new MText();

        mText.SetDatabaseDefaults();

        mText.Width = 100;

        mText.Height = 50;

        mText.SetContentsRtf("MLeader");

        mText.Location = new Point3d(4, 2, 0);

 

        leader.MText = mText;

 

        int idx = leader.AddLeaderLine(new Point3d(1, 1, 0));

        leader.AddFirstVertex(idx, new Point3d(0, 0, 0));

 

        model.AppendEntity(leader);

        Tx.AddNewlyCreatedDBObject(leader, true);

 

        Tx.Commit();

    }

}

 

The second creates a MLeader with a Block content. It also handles the case where the MLeader block contains attributes and set them to a default value:

 

[CommandMethod("netBlockMLeader")]

public static void netBlockMLeader()

{

    Document doc = Application.DocumentManager.MdiActiveDocument;

    Database db = doc.Database;

    Editor ed = doc.Editor;

 

    using (Transaction Tx = db.TransactionManager.StartTransaction())

    {

        BlockTable table = Tx.GetObject(

            db.BlockTableId,

     &#
160;      OpenMode.ForRead)

                as BlockTable;

 

        BlockTableRecord model = Tx.GetObject(

            table[BlockTableRecord.ModelSpace],

            OpenMode.ForWrite)

                as BlockTableRecord;

 

        if (!table.Has("BlkLeader"))

        {

            ed.WriteMessage(

                "\nYou need to define a \"BlkLeader\" first…");

            return;

        }

 

        MLeader leader = new MLeader();

        leader.SetDatabaseDefaults();

 

    
    leader.ContentType = ContentType.BlockContent;

 

        leader.BlockContentId = table["BlkLeader"];

        leader.BlockPosition = new Point3d(4, 2, 0);

 

        int idx = leader.AddLeaderLine(new Point3d(1, 1, 0));

        leader.AddFirstVertex(idx, new Point3d(0, 0, 0));

 

        //Handle Block Attributes

        int AttNumber = 0;

        BlockTableRecord blkLeader = Tx.GetObject(

            leader.BlockContentId,

            OpenMode.ForRead)

                as BlockTableRecord;

 

        //Doesn’t take in consideration oLeader.BlockRotation

        Matrix3d Transfo = Matrix3d.Displacement(

            leader.BlockPosition.GetAsVector());

 

        foreach (ObjectId blkEntId in blkLeader)

        {

            AttributeDefinition AttributeDef = Tx.GetObject(

                blkEntId,

                OpenMode.ForRead)

                    as AttributeDefinition;

 

            if (AttributeDef != null)

            {

                AttributeReference AttributeRef =

                    new AttributeReference();

 

                AttributeRef.SetAttributeFromBlock(

                    AttributeDef,

                    Transfo);

 

                AttributeRef.Position =

                    AttributeDef.Position.TransformBy(Transfo);

 

                AttributeRef.TextString = "Attrib #" + (++AttNumber);

 

                leader.SetBlockAttribute(blkEntId, AttributeRef);

            }

        }

 

        model.AppendEntity(leader);

        Tx.AddNewlyCreatedDBObject(leader, true);

 

        Tx.Commit();

    }

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