Use Database.GetViewports

布局自己本身就是一个视口。

Use Database.GetViewports(true)

依次返回的是，模型空间中的视口、布局一本身、布局一中的视口、布局二本身、布局二中的视口。

Use Database.GetViewports(false)

返回的是布局中的视口。排除了模型空间中的视口和布局本身。一般这个才是我们所最需要的。

通过遍历Layout中的视口依次返回的是：布局一本身、布局一中的视口、布局二本身、布局二中的视口。

GridBoundToLimits可以区分视口是布局还是布局中的视口。True为布局中的视口。

下面是测试代码。

    [CommandMethod("Test")]
    public void Test()
    {
      Document doc = AcadApp.DocumentManager.MdiActiveDocument;
      Database db = doc.Database;
      Editor ed = doc.Editor;
      ed.WriteMessage("use my Func:\n");
      ObjectIdCollection myViewports = new ObjectIdCollection();
      using (Transaction trans = db.TransactionManager.StartTransaction())
      {
        DBDictionary layoutDict = trans.GetObject(db.LayoutDictionaryId, OpenMode.ForRead) as DBDictionary;
        foreach (var layoutId in layoutDict)
        {
          Layout lout = trans.GetObject(layoutId.Value, OpenMode.ForRead) as Layout;
          if (lout == null)
          {
            continue;
          }
          var vports = lout.GetViewports();
          foreach (var item in vports)
          {
            myViewports.Add((ObjectId)item);
          }
        }
        ed.WriteMessage(myViewports.Count.ToString() + "\n");
        foreach (ObjectId id in myViewports)
        {
          ed.WriteMessage(string.Format("{0} IsErased = '{1}'\n", id.Handle, id.IsErased));
        }
      }

      ed.WriteMessage("\nUse Database.GetViewports(true):\n");
      var viewports = db.GetViewports(true);
      ed.WriteMessage(viewports.Count.ToString() + "\n");
      foreach (ObjectId id in viewports)
      {
        ed.WriteMessage(string.Format("{0} IsErased = '{1}'\n", id.Handle, id.IsErased));
      }

      ed.WriteMessage("\nUse Database.GetViewports(false):\n");
      var viewportsfalse = db.GetViewports(false);
      ed.WriteMessage(viewportsfalse.Count.ToString() + "\n");
      foreach (ObjectId id in viewportsfalse)
      {
        ed.WriteMessage(string.Format("{0} IsErased = '{1}'\n", id.Handle, id.IsErased));
      }
    }