select blocks only

selectBlocksOnly

[CommandMethod("selectBlocksOnly")]
public void selectBlocksOnly()
{
  Document acadDoc = Application.DocumentManager.MdiActiveDocument;
  Editor editor = acadDoc.Editor;
  PromptSelectionOptions promptSelOpt = new PromptSelectionOptions();
  promptSelOpt.MessageForAdding = "Select block objects: ";
  TypedValue[] tVs = new TypedValue[] { new TypedValue((int)DxfCode.Start, RXClass.GetClass(typeof(BlockReference)).DxfName) };
  SelectionFilter filter = new SelectionFilter(tVs);
  PromptSelectionResult result = editor.GetSelection(promptSelOpt, filter);
  int index = 1;
  if (result.Status == PromptStatus.OK)
  {
    using (Transaction trans = acadDoc.Database.TransactionManager.StartOpenCloseTransaction())
    {
      foreach (SelectedObject selObj in result.Value)
      {
        BlockReference blockRef = trans.GetObject(selObj.ObjectId, OpenMode.ForRead) as BlockReference;
        editor.WriteMessage("\nObject " + index.ToString() + " in selection set is type: " + blockRef.GetRXClass().DxfName + " Named: " + blockRef.Name);
        index++;
      }
      trans.Commit();
    } 
  }
}