AutoCAD: Drag and Drop *.dwg files from my ListBox hosted in Palettset
[CommandMethod("InsertDWG")]
static public void SendCmd()
{
    string DWGFile = @"D:sym1047.DWG";
    string InsertCmd = @"_.-INSERT " + DWGFile + 'r' + 'n';
    Document doc = Application.DocumentManager.MdiActiveDocument;
    doc.SendStringToExecute(InsertCmd, true, false, false);
}