TreeViewEventArgs 類別

定義

命名空間:

System.Windows.Forms

組件:

System.Windows.Forms.dll

提供 AfterCheck 控制項的 AfterCollapse、AfterExpand、AfterSelect 或 TreeView 事件資料。

public ref class TreeViewEventArgs : EventArgs

public class TreeViewEventArgs : EventArgs

type TreeViewEventArgs = class
    inherit EventArgs

Public Class TreeViewEventArgs
Inherits EventArgs

繼承

Object

EventArgs

TreeViewEventArgs

範例

下列範例說明自訂 TreeView 的 。 藉由繼承 TreeView 類別，這個自訂版本具有一般 TreeView 的所有功能。 變更建構函式中的各種屬性值可提供獨特的外觀。 ShowPlusMinus因為 屬性設定為 false，所以自訂控制項也會覆寫 OnAfterSelect 方法，以便在按一下節點時展開和折迭。

透過這種方式自訂的控制項可以在整個組織中使用，讓您輕鬆地提供一致的介面，而不需要在每個個別專案中指定控制項屬性。

public ref class CustomizedTreeView: public TreeView
{
public:
   CustomizedTreeView()
   {

      // Customize the TreeView control by setting various properties.
      BackColor = System::Drawing::Color::CadetBlue;
      FullRowSelect = true;
      HotTracking = true;
      Indent = 34;
      ShowPlusMinus = false;

      // The ShowLines property must be false for the FullRowSelect
      // property to work.
      ShowLines = false;
   }

protected:
   virtual void OnAfterSelect( TreeViewEventArgs^ e ) override
   {
      // Confirm that the user initiated the selection.
      // This prevents the first node from expanding when it is
      // automatically selected during the initialization of
      // the TreeView control.
      if ( e->Action != TreeViewAction::Unknown )
      {
         if ( e->Node->IsExpanded )
         {
            e->Node->Collapse();
         }
         else
         {
            e->Node->Expand();
         }
      }

      
      // Remove the selection. This allows the same node to be
      // clicked twice in succession to toggle the expansion state.
      SelectedNode = nullptr;
   }
};

public class CustomizedTreeView : TreeView
{
    public CustomizedTreeView()
    {
        // Customize the TreeView control by setting various properties.
        BackColor = System.Drawing.Color.CadetBlue;
        FullRowSelect = true;
        HotTracking = true;
        Indent = 34;
        ShowPlusMinus = false;

        // The ShowLines property must be false for the FullRowSelect 
        // property to work.
        ShowLines = false;
    }

    protected override void OnAfterSelect(TreeViewEventArgs e)
    {
        // Confirm that the user initiated the selection.
        // This prevents the first node from expanding when it is
        // automatically selected during the initialization of 
        // the TreeView control.
        if (e.Action != TreeViewAction.Unknown)
        {
            if (e.Node.IsExpanded) 
            {
                e.Node.Collapse();
            }
            else 
            {
                e.Node.Expand();
            }
        }

        // Remove the selection. This allows the same node to be
        // clicked twice in succession to toggle the expansion state.
        SelectedNode = null;
    }
}

Public Class CustomizedTreeView
    Inherits TreeView

    Public Sub New()
        ' Customize the TreeView control by setting various properties.
        BackColor = System.Drawing.Color.CadetBlue
        FullRowSelect = True
        HotTracking = True
        Indent = 34
        ShowPlusMinus = False

        ' The ShowLines property must be false for the FullRowSelect 
        ' property to work.
        ShowLines = False
    End Sub


    Protected Overrides Sub OnAfterSelect(ByVal e As TreeViewEventArgs)
        ' Confirm that the user initiated the selection.
        ' This prevents the first node from expanding when it is
        ' automatically selected during the initialization of 
        ' the TreeView control.
        If e.Action <> TreeViewAction.Unknown Then
            If e.Node.IsExpanded Then
                e.Node.Collapse()
            Else
                e.Node.Expand()
            End If
        End If

        ' Remove the selection. This allows the same node to be
        ' clicked twice in succession to toggle the expansion state.
        SelectedNode = Nothing
    End Sub

End Class

備註

如需處理事件的詳細資訊，請參閱 處理和引發事件。

建構函式

TreeViewEventArgs(TreeNode)	初始化指定樹狀節點之 TreeViewEventArgs 類別的新執行個體。
TreeViewEventArgs(TreeNode, TreeViewAction)	初始化指定樹狀節點和使用引發事件的動作型別來初始化 TreeViewEventArgs 類別的新執行個體。

屬性

Action	取得引發事件的動作類型。
Node	取得已核取、展開、收合或選取的樹狀節點。

方法

Equals(Object)	判斷指定的物件是否等於目前的物件。 (繼承來源 Object)
GetHashCode()	做為預設雜湊函式。 (繼承來源 Object)
GetType()	取得目前執行個體的 Type。 (繼承來源 Object)
MemberwiseClone()	建立目前 Object 的淺層複製。 (繼承來源 Object)
ToString()	傳回代表目前物件的字串。 (繼承來源 Object)

另請參閱

• TreeViewCancelEventArgs