Using ActiveX API GetBoundingBox in .NET

By Virupaksha Aithal

Below code shows the procedure to use activeX API GetBoundingBox in AutoCAD.NET. As GetBoundingBox returns the points, we need to “InvokeMember” member with “ParameterModifier” parameters.

[CommandMethod("GetBoundingBox")]
static public void GetBoundingBox()
{
    Document doc = Application.DocumentManager.MdiActiveDocument;
    Database db = doc.Database;
    Editor ed = doc.Editor;
 
    PromptEntityOptions options =
          new PromptEntityOptions("nSelect an entity");
 
    PromptEntityResult acSSPrompt = ed.GetEntity(options);
    if (acSSPrompt.Status != PromptStatus.OK)
    return;
    // obtain transaction manager
    using (Transaction Tx = db.TransactionManager.StartTransaction())
    {
        Entity text = Tx.GetObject(acSSPrompt.ObjectId, 
                                         OpenMode.ForRead) as Entity;
 
        object oAcadObjpl1 = text.AcadObject;
 
        object[] argspl1 = new object[2];
        argspl1[0] = new VariantWrapper(0);
        argspl1[1] = new VariantWrapper(0);
        ParameterModifier pmpl1 = new ParameterModifier(2);
        pmpl1[0] = true;
        pmpl1[1] = true;
 
        ParameterModifier[] modifierspl1 = 
            new ParameterModifier[] { pmpl1 };
        oAcadObjpl1.GetType().InvokeMember("GetBoundingBox", 
               BindingFlags.InvokeMethod, null, oAcadObjpl1, argspl1, 
               modifierspl1, null, null);
        Point3d pt1 = 
            new Point3d((double[])argspl1[0]);
        Point3d pt2 = 
            new Point3d((double[])argspl1[1]);
        ed.WriteMessage("n");
        ed.WriteMessage(pt1.X + "," + pt1.Y + "," + pt1.Z + "n");
        ed.WriteMessage(pt2.X + "," + pt2.Y + "," + pt2.Z + "n");
 
        Tx.Commit();
    }
}