WinForm TreeView节点重绘，失去焦点的高亮显示

   当用户焦点离开TreeView时，TreeView选中节点仍然高亮，但是颜色符合主题。

   设置TreeView.HideSelection = False;可让选中节点保持高亮。

  添加重绘事件

  TreeView.DrawMode = TreeViewDrawMode.OwnerDrawText;

  TreeView.DrawNode += new DrawTreeNodeEventHandler(TreeView_DrawNode);

// Draws a node.

 private void TreeView_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);    

    }   

  } 

}