BetterExplorer.MainWindow.newt_DragEnter C# (CSharp) Method

    void newt_DragEnter(object sender, DragEventArgs e) {
      e.Handled = true;
      this._CurrentlySelectedItem = tcMain.SelectedItem as Wpf.Controls.TabItem;
      var tabItem = e.Source as Wpf.Controls.TabItem;
      if (tabItem == null) return;

      this._TabDropData = (System.Runtime.InteropServices.ComTypes.IDataObject)e.Data;

      if ((sender as Wpf.Controls.TabItem).ShellObject.IsFileSystem)
        e.Effects = (e.KeyStates & DragDropKeyStates.ControlKey) == DragDropKeyStates.ControlKey ? DragDropEffects.Copy : DragDropEffects.Move;
      else
        e.Effects = DragDropEffects.None;

      var ptw = new BExplorer.Shell.DataObject.Win32Point();
      GetCursorPos(ref ptw);
      e.Effects = DragDropEffects.None;
      var tabItemSource = e.Data.GetData(typeof(Wpf.Controls.TabItem)) as Wpf.Controls.TabItem;

      if (tabItemSource == null) {
        var wpt = new BExplorer.Shell.DataObject.Win32Point() { X = ptw.X, Y = ptw.Y };
        DropTarget.Create.DragEnter(this.Handle, (System.Runtime.InteropServices.ComTypes.IDataObject)e.Data, ref wpt, (int)e.Effects);
      } else if (e.Data.GetDataPresent(typeof(Wpf.Controls.TabItem))) {
        e.Effects = DragDropEffects.Move;
      }
    }