如何更改treenode矩形尺寸？

Question

我想我的树视图显示为folows。

这是我正在使用的代码。

procedure TForm1.FormShow(Sender: TObject); 
begin 
    TreeView1.FullExpand 
end; 

procedure TForm1.TreeView1CustomDrawItem(Sender: TCustomTreeView; 
    Node: TTreeNode; State: TCustomDrawState; var DefaultDraw: Boolean); 

const 
    _Right = 100; 
    _Left = 50; 

var 
    R : TRect; 

begin 

if Node.Level = 0 then 
begin 

    R := Node.DisplayRect(true); 

    R.Right := R.Right + _Right; 
    R.Left := R.Left + _Left; 

    Sender.Canvas.Brush.Color := clRed; 
    Sender.Canvas.FillRect(R); 

end; 

end; 

的问题是，我可以延长R.right但如果在OnAdvancedCustomDrawItem事件进行绘制，不能扩展R.left ...

Answer 1

，也有更多的选择。

这确实对我来说（过滤掉cdPostPaint阶段）：

procedure TForm1.TreeView1AdvancedCustomDrawItem(Sender: TCustomTreeView; 
    Node: TTreeNode; State: TCustomDrawState; Stage: TCustomDrawStage; 
    var PaintImages, DefaultDraw: Boolean); 
const 
    _Right = 100; 
    _Left = 50; 
var 
    R : TRect; 
begin 
if (Node.Level = 0) and (stage = cdPostPaint) then 
begin 

    R := Node.DisplayRect(true); 
    R.Right := R.Right + 2; 
    Sender.Canvas.FillRect(R); // Just clear default text area 

    R.Right := R.Right + _Right; 
    R.Left := R.Left + _Left; 
    Sender.Canvas.Brush.Color := clRed; 
    Sender.Canvas.FillRect(R); 
    {- Make sure writing text with transparent background } 
    SetBkMode(Sender.Canvas.Handle, TRANSPARENT); 
    Sender.Canvas.TextOut(R.Left,R.Top,Node.Text); 
    PaintImages := true; 
    DefaultDraw := false; 
end;  
end;