Changing the backcolor of a childnode in the treeview

Question

As per TreeView Remove CheckBox by some Nodes

After doing so I have my tree-view of check-box without parent node check-box. But I am facing a problem, I am not able to change the color of a particular child node.

ie. if i try to change like

treeview1.Nodes[0].Nodes[2].BackColor=Color.Gray;

is still having the same old color. Can anyone help me on this. Thanks.

Edited

private const int TVIF_STATE = 0x8; private const int TVIS_STATEIMAGEMASK = 0xF000; private const int TV_FIRST = 0x1100; private const int TVM_SETITEM = TV_FIRST + 63; [StructLayout(LayoutKind.Sequential, Pack = 8, CharSet = CharSet.Auto)] private struct TVITEM { public int mask; public IntPtr hItem; public int state; public int stateMask; [MarshalAs(UnmanagedType.LPTStr)] public string lpszText; public int cchTextMax; public int iImage; public int iSelectedImage; public int cChildren; public IntPtr lParam; } [DllImport("user32.dll", CharSet = CharSet.Auto)] private static extern IntPtr SendMessage(IntPtr hWnd, int Msg, IntPtr wParam, ref TVITEM lParam); /// <summary> /// Hides the checkbox for the specified node on a TreeView control. /// </summary> private void HideCheckBox(TreeView tvw, TreeNode node) { TVITEM tvi = new TVITEM(); tvi.hItem = node.Handle; tvi.mask = TVIF_STATE; tvi.stateMask = TVIS_STATEIMAGEMASK; tvi.state = 0; SendMessage(tvw.Handle, TVM_SETITEM, IntPtr.Zero, ref tvi); } /// <summary> /// Handles the DrawNode event of the treeView1 control. /// </summary> /// <param name="sender">The source of the event.</param> /// <param name="e">The <see cref="System.Windows.Forms.DrawTreeNodeEventArgs"/> instance containing the event data.</param> /// <remarks></remarks> private void treeView1_DrawNode(object sender, DrawTreeNodeEventArgs e) { if (e.Node.Level == 0) HideCheckBox(e.Node.TreeView, e.Node); e.DrawDefault = true; } private void treeView1_AfterSelect(object sender, TreeViewEventArgs e) { treeView1.Nodes[0].Nodes[1].BackColor = Color.Red; }

I tested it and it worked OK for me. Where do you call this treeview1.Nodes[0].Nodes[2].BackColor=Color.Gray;? — King King
– King King, Commented Oct 4, 2013 at 10:52
i am calling it on treeView1_AfterSelect King. have ur parent node is of checkbox ? — Abin
– Abin, Commented Oct 4, 2013 at 10:54
Well, tested and it also works. your problem is strange enough. — King King
– King King, Commented Oct 4, 2013 at 10:57
I've done exactly what you described. I used the code of Cody Gray from the link you posted, hide the checkbox I want, then add the code you posted in a AfterSelect event handler, that's all. It works normally. — King King
– King King, Commented Oct 4, 2013 at 11:06

King King · Accepted Answer · 2013-10-04 11:33:29Z

I've tried it the way you did (specially the DrawNode event handler) and I'm pretty sure that you set TreeView.DrawMode = TreeViewDrawMode.OwnerDrawText;. That won't draw the Background (just Text only) so that's why the BackColor is not updated. You have to set it to TreeViewDrawMode.OwnerDrawAll instead:

I would use another approach to Hide all the Child node checkboxes without using DrawNode event handler. I would add code to the BeforeExpand like this:

 //BeforeExpand event handler for your TreeView private void treeView1_BeforeExpand(object sender, TreeViewCancelEventArgs e){ foreach (TreeNode node in e.Node.Nodes) HideCheckBox(e.Node.TreeView, e.Node); }

You can also loop through all the nodes with level>0 to hide the checkbox once. Then whenever you add more nodes to your TreeView, if it's not level 0 node, just HideCheckBox right after adding it.

NOTE: Of course the 2 approaches I mentioned above don't require you to set DrawMode to anything other than Normal.

Thanks King this was the problem... i was using OwnerDrawText instead of OwnerDrawAll
@Abin yes, that's what I mentioned in my answer. However I recommend you to use the 2 approaches I posted in my answer. Using BeforeExpand is the cleanest way.

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