TreeNodeCollection.Clear 方法

定义

命名空间:

System.Windows.Forms

程序集:

System.Windows.Forms.dll

从集合中删除所有树节点。

public:
 virtual void Clear();

public virtual void Clear ();

abstract member Clear : unit -> unit
override this.Clear : unit -> unit

Public Overridable Sub Clear ()

实现

Clear()

示例

下面的代码示例将TreeNodeCollection数组TreeView的内容复制到临时Array数组，然后使用该方法AddRange将数组的内容添加到另一个TreeView数组中。 使用TreeNodeCollectionClear该方法清除源TreeView中的源。 此示例要求你有两 TreeView 个控件，一个控件包含一个对象集合 TreeNode 。

private:
   void MyButtonAddAllClick( Object^ /*sender*/, EventArgs^ /*e*/ )
   {
      
      // Get the 'myTreeNodeCollection' from the 'myTreeViewBase' TreeView.
      TreeNodeCollection^ myTreeNodeCollection = myTreeViewBase->Nodes;
      
      // Create an array of 'TreeNodes'.
      array<TreeNode^>^myTreeNodeArray = gcnew array<TreeNode^>(myTreeViewBase->Nodes->Count);
      
      // Copy the tree nodes to the 'myTreeNodeArray' array.
      myTreeViewBase->Nodes->CopyTo( myTreeNodeArray, 0 );
      
      // Remove all the tree nodes from the 'myTreeViewBase' TreeView.
      myTreeViewBase->Nodes->Clear();
      
      // Add the 'myTreeNodeArray' to the 'myTreeViewCustom' TreeView.
      myTreeViewCustom->Nodes->AddRange( myTreeNodeArray );
   }

private void MyButtonAddAllClick(object sender, EventArgs e)
{
   // Get the 'myTreeNodeCollection' from the 'myTreeViewBase' TreeView.
   TreeNodeCollection myTreeNodeCollection = myTreeViewBase.Nodes;
   // Create an array of 'TreeNodes'.
   TreeNode[] myTreeNodeArray = new TreeNode[myTreeViewBase.Nodes.Count];
   // Copy the tree nodes to the 'myTreeNodeArray' array.
   myTreeViewBase.Nodes.CopyTo(myTreeNodeArray,0);
   // Remove all the tree nodes from the 'myTreeViewBase' TreeView.
   myTreeViewBase.Nodes.Clear();
   // Add the 'myTreeNodeArray' to the 'myTreeViewCustom' TreeView.
   myTreeViewCustom.Nodes.AddRange(myTreeNodeArray);
}

Private Sub MyButtonAddAllClick(sender As Object, e As EventArgs)
   ' Get the 'myTreeNodeCollection' from the 'myTreeViewBase' TreeView.
   Dim myTreeNodeCollection As TreeNodeCollection = myTreeViewBase.Nodes
   ' Create an array of 'TreeNodes'.
   Dim myTreeNodeArray(myTreeViewBase.Nodes.Count-1) As TreeNode
   ' Copy the tree nodes to the 'myTreeNodeArray' array.
   myTreeViewBase.Nodes.CopyTo(myTreeNodeArray, 0)
   ' Remove all the tree nodes from the 'myTreeViewBase' TreeView.
   myTreeViewBase.Nodes.Clear()
   ' Add the 'myTreeNodeArray' to the 'myTreeViewCustom' TreeView.
      myTreeViewCustom.Nodes.AddRange(myTreeNodeArray)
End Sub

注解

可以使用此方法从树视图中清除树节点的整个集合。

若要从集合中删除单个树节点，请使用 Remove 或 RemoveAt 方法。

若要向集合添加新TreeNode对象，请使用Add或AddRangeInsert方法。