/// <summary>
/// 连接到可视父元素，连接成功，则返回 true。
/// </summary>
/// <returns></returns>
private bool TryConnect()
{
if (!this.IsConnected)
{
this._cellsPresenter = ItemsControl.GetItemsOwner(this) as TreeGridCellsPresenter;
if (this._cellsPresenter != null)
{
this._cellsPresenter.InternalItemsHost = this;
var row = this._cellsPresenter.Row;
if (row != null)
{
row.CellsPanel = this;
this._treeGrid = row.TreeGrid;
if (this._treeGrid != null)
{
InternalCollectionChangedEventManager.AddListener(this._treeGrid.Columns, this);
this._rowsPanel = this._treeGrid.RowsPanel;
//分组显示时，RowsPanel 为 null，也不能进行虚拟化操作。
this._isVirtualizing = this._rowsPanel != null && this._treeGrid.IsColumnsVirtualizingEnabled;
this._isRecycleMode = this._treeGrid.IsRecycleMode;
}
}
}
}
return(this.IsConnected);
}
/// <summary>
/// 子类在 Measure 时，调用此方法来连接到 TreeGrid，并同步一些必要的属性。
/// </summary>
internal void ConnectToGrid()
{
if (_treeGrid == null)
{
_treeGrid = this.GetVisualParent <TreeGrid>();
if (_treeGrid != null)
{
_columns = _treeGrid.Columns;
InternalCollectionChangedEventManager.AddListener(_columns, this);
}
}
}
