Disable and change color of node in Treeview

Question

I am looking for the way of disabling proper nodes.

Let's say I have created simple treeview structure like below:

Parent 1 (disable)
Parent 2
- Child 1
- Child 2 (disable)

So far I have found workaround how to do that, but it still doesn't work good at all. I use OnChanging event handler:

procedure TForm1.TreeViewChanging(Sender: TObject; Node: TTreeNode;
  var AllowChange: Boolean); 
begin
   if (Node.Text = 'Parent 1') or (Node.Text = 'Child 1') then
      AllowChange := False;
end;

It works, because I can't click on this node, but the issue is that after 'disabling' node this way, the color of Parent 1 and Child 1 nodes is the same as other. Is it any way to change color of this nodes (grey)? Or maybe you know another way to disabling nodes in TTreeView component?

@DavidHeffernan I've tried that, but unfortunately it doesn't work in my case. It does nothing... — astack, Sep 22 '16 at 17:38
XP perhaps? TVIS_EX_DISABLED is Vista onward. Or perhaps no runtime themes.. — Sertac Akyuz, Sep 22 '16 at 17:52
In Win7 I can confirm what @David said, Setting `Enabled` to `False` disables the item but also changes the items color to grey. The difference is not very striking if the font color is the standard `clBlack` but still visible. — Tom Brunberg, Sep 22 '16 at 18:17
Yes, it's weird, but I still need do find workaround for that... Is it any chance to change node color for this disabled items? — astack, Sep 22 '16 at 18:35
@astack - You can draw the items yourself. You should probably find why "enabled" doesn't work though. Did you try with a brand new project? — Sertac Akyuz, Sep 22 '16 at 18:46
Find *workaround for what* exactly? The faint difference in shading? Draw the item yourself and paint the disabled items in whatever shade or color you want (Windows uses the default enabled/disabled colors with which the user should already be familiar). Enabled works fine; it prevents selection and alters the shading of the item to show it's disabled. — Ken White, Sep 22 '16 at 22:29

Tom Brunberg · Accepted Answer · 2016-09-22T22:44:53.100

5

To disable a node, set its Enabled property to False. A disabled item is displayed in gray color.

To change the normal color of a nodes text, change TTreeView.Font.Color.

To change the color of a disabled nodes text, use the OnCustomDrawItemevent:

procedure TForm2.TreeView1CustomDrawItem(Sender: TCustomTreeView;
  Node: TTreeNode; State: TCustomDrawState; var DefaultDraw: Boolean);
begin
  if cdsDisabled in state then
    Sender.Canvas.Font.Color := clRed; //cl3DLight;
end;

Default color settings:

Disabled color = cl3DLight:

Normal text color = clGreen and disabled color = clRed:

edited Sep 22 '16 at 22:44

answered Sep 22 '16 at 22:29

Tom Brunberg

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2

Perhaps some commentary on Enabled would be nice. So that future readers can know that it does work. – David Heffernan Sep 22 '16 at 22:35
I did it exactly as you and it works for me. First I disabled proper nodes in my treeview and next I used 'OnCustomDrawItem' event to color this nodes on grey color. Thanks! – astack Sep 23 '16 at 15:26

Disable and change color of node in Treeview

1 Answers1