TreeNodeStates 枚举

定义

定义表示 TreeNode 的可能状态的常数。Defines constants that represent the possible states of a TreeNode.

此枚举有一个 FlagsAttribute 属性,允许按位组合成员值。

public enum class TreeNodeStates
[System.Flags]
public enum TreeNodeStates
type TreeNodeStates = 
Public Enum TreeNodeStates
继承
TreeNodeStates
属性

字段

Checked 8

已选中该节点。The node is checked.

Default 32

该节点处于其默认状态。The node is in its default state.

Focused 16

该节点有焦点。The node has focus.

Grayed 2

该节点已禁用。The node is disabled.

Hot 64

该节点为热节点。The node is hot. 此状态发生在 HotTracking 属性设置为 true 且鼠标指针位于该节点上时。This state occurs when the HotTracking property is set to true and the mouse pointer is over the node.

Indeterminate 256

该节点处于不确定状态。The node in an indeterminate state.

Marked 128

该节点已标记。The node is marked.

Selected 1

该节点已选择。The node is selected.

ShowKeyboardCues 512

该节点应指示一个键盘快捷键。The node should indicate a keyboard shortcut.

示例

下面的示例演示如何使用所有者描述TreeView自定义控件。The following example demonstrates how to customize a TreeView control using owner drawing. 该示例中的控件在常规节点标签旁边显示可选节点标记。TreeViewThe TreeView control in the example displays optional node tags alongside the normal node labels. 节点标记是使用属性指定TreeNode.Tag的。Node tags are specified using the TreeNode.Tag property. TreeView控件还使用自定义的突出显示颜色。The TreeView control also uses custom colors, including a custom highlight color.

您可以通过设置颜色属性TreeView自定义大多数颜色, 但无法将选择突出显示颜色作为属性提供。You can customize most of the TreeView colors by setting color properties, but the selection highlight color is not available as a property. 此外, 默认选择突出显示矩形仅扩展到节点标签周围。Additionally, the default selection highlight rectangle extends only around a node label. 必须使用所有者绘图来绘制节点标记, 并绘制一个足以容纳节点标记的自定义突出显示矩形。Owner drawing must be used to draw the node tags and to draw a customized highlight rectangle large enough to include a node tag.

在此示例中, TreeView.DrawNode事件的处理程序通过调用DrawTreeNodeEventArgs类的方法来绘制未选定的节点。In the example, a handler for the TreeView.DrawNode event draws unselected nodes by calling methods of the DrawTreeNodeEventArgs class. 这些方法为不需要自定义TreeView的元素提供默认外观。These methods provide the default appearance for TreeView elements that do not need customization. 处理程序手动绘制节点标记和自定义选择突出显示。The handler draws the node tags and the custom selection highlight manually.

有关完整的示例, 请参阅TreeView.DrawNode参考主题。For the complete example, see the TreeView.DrawNode reference topic.

   // Draws a node.
private:
   void myTreeView_DrawNode( Object^ sender, DrawTreeNodeEventArgs^ e )
   {
      // Draw the background and node text for a selected node.
      if ( (e->State & TreeNodeStates::Selected) != (TreeNodeStates)0 )
      {
         // Draw the background of the selected node. The NodeBounds
         // method makes the highlight rectangle large enough to
         // include the text of a node tag, if one is present.
         e->Graphics->FillRectangle( Brushes::Green, NodeBounds( e->Node ) );

         // Retrieve the node font. If the node font has not been set,
         // use the TreeView font.
         System::Drawing::Font^ nodeFont = e->Node->NodeFont;
         if ( nodeFont == nullptr )
                  nodeFont = (dynamic_cast<TreeView^>(sender))->Font;

         // Draw the node text.
         e->Graphics->DrawString( e->Node->Text, nodeFont, Brushes::White, Rectangle::Inflate( e->Bounds, 2, 0 ) );
      }
      // Use the default background and node text.
      else
      {
         e->DrawDefault = true;
      }

      // If a node tag is present, draw its string representation 
      // to the right of the label text.
      if ( e->Node->Tag != nullptr )
      {
         e->Graphics->DrawString( e->Node->Tag->ToString(), tagFont, Brushes::Yellow, (float)e->Bounds.Right + 2, (float)e->Bounds.Top );
      }

      
      // If the node has focus, draw the focus rectangle large, making
      // it large enough to include the text of the node tag, if present.
      if ( (e->State & TreeNodeStates::Focused) != (TreeNodeStates)0 )
      {
         Pen^ focusPen = gcnew Pen( Color::Black );
         try
         {
            focusPen->DashStyle = System::Drawing::Drawing2D::DashStyle::Dot;
            Rectangle focusBounds = NodeBounds( e->Node );
            focusBounds.Size = System::Drawing::Size( focusBounds.Width - 1, focusBounds.Height - 1 );
            e->Graphics->DrawRectangle( focusPen, focusBounds );
         }
         finally
         {
            if ( focusPen )
               delete safe_cast<IDisposable^>(focusPen);
         }

      }
   }
// Draws a node.
private void myTreeView_DrawNode(
    object sender, DrawTreeNodeEventArgs e)
{
    // Draw the background and node text for a selected node.
    if ((e.State & TreeNodeStates.Selected) != 0)
    {
        // Draw the background of the selected node. The NodeBounds
        // method makes the highlight rectangle large enough to
        // include the text of a node tag, if one is present.
        e.Graphics.FillRectangle(Brushes.Green, NodeBounds(e.Node));

        // Retrieve the node font. If the node font has not been set,
        // use the TreeView font.
        Font nodeFont = e.Node.NodeFont;
        if (nodeFont == null) nodeFont = ((TreeView)sender).Font;

        // Draw the node text.
        e.Graphics.DrawString(e.Node.Text, nodeFont, Brushes.White,
            Rectangle.Inflate(e.Bounds, 2, 0));
    }

    // Use the default background and node text.
    else 
    {
        e.DrawDefault = true;
    }

    // If a node tag is present, draw its string representation 
    // to the right of the label text.
    if (e.Node.Tag != null)
    {
        e.Graphics.DrawString(e.Node.Tag.ToString(), tagFont,
            Brushes.Yellow, e.Bounds.Right + 2, e.Bounds.Top);
    }

    // If the node has focus, draw the focus rectangle large, making
    // it large enough to include the text of the node tag, if present.
    if ((e.State & TreeNodeStates.Focused) != 0)
    {
        using (Pen focusPen = new Pen(Color.Black))
        {
            focusPen.DashStyle = System.Drawing.Drawing2D.DashStyle.Dot;
            Rectangle focusBounds = NodeBounds(e.Node);
            focusBounds.Size = new Size(focusBounds.Width - 1, 
            focusBounds.Height - 1);
            e.Graphics.DrawRectangle(focusPen, focusBounds);
        }
    }
}
' Draws a node.
Private Sub myTreeView_DrawNode(ByVal sender As Object, _
    ByVal e As DrawTreeNodeEventArgs) Handles myTreeView.DrawNode

    ' Draw the background and node text for a selected node.
    If (e.State And TreeNodeStates.Selected) <> 0 Then

        ' Draw the background of the selected node. The NodeBounds
        ' method makes the highlight rectangle large enough to
        ' include the text of a node tag, if one is present.
        e.Graphics.FillRectangle(Brushes.Green, NodeBounds(e.Node))

        ' Retrieve the node font. If the node font has not been set,
        ' use the TreeView font.
        Dim nodeFont As Font = e.Node.NodeFont
        If nodeFont Is Nothing Then
            nodeFont = CType(sender, TreeView).Font
        End If

        ' Draw the node text.
        e.Graphics.DrawString(e.Node.Text, nodeFont, Brushes.White, _
            e.Bounds.Left - 2, e.Bounds.Top)

    ' Use the default background and node text.
    Else
        e.DrawDefault = True
    End If

    ' If a node tag is present, draw its string representation 
    ' to the right of the label text.
    If (e.Node.Tag IsNot Nothing) Then
        e.Graphics.DrawString(e.Node.Tag.ToString(), tagFont, _
            Brushes.Yellow, e.Bounds.Right + 2, e.Bounds.Top)
    End If

    ' If the node has focus, draw the focus rectangle large, making
    ' it large enough to include the text of the node tag, if present.
    If (e.State And TreeNodeStates.Focused) <> 0 Then
        Dim focusPen As New Pen(Color.Black)
        Try
            focusPen.DashStyle = System.Drawing.Drawing2D.DashStyle.Dot
            Dim focusBounds As Rectangle = NodeBounds(e.Node)
            focusBounds.Size = New Size(focusBounds.Width - 1, _
                focusBounds.Height - 1)
            e.Graphics.DrawRectangle(focusPen, focusBounds)
        Finally
            focusPen.Dispose()
        End Try
    End If

End Sub

注解

此枚举由State DrawTreeNodeEventArgs类的属性使用。This enumeration is used by the State property of the DrawTreeNodeEventArgs class. 有关详细信息,请参阅 TreeView.DrawNode 事件。For more information, see the TreeView.DrawNode event.

适用于

另请参阅