Customize treeview

Question

Is there a way to customize a winform treeview to get something like ?

The purpose is to have one color by parent item an define a triangle instead of +/- icons to develop item.

Answer 1

update: I posted a more complete solution there.

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Use TreeViewDrawMode.OwnerDrawText so the indenting will be adjusted by the TreeView. Apart from that, you should implement the full painting.

public sealed class AdvancedTreeView : TreeView
{
    public AdvancedTreeView()
    {
        DrawMode = TreeViewDrawMode.OwnerDrawText;
        ShowLines = false;
        AlternateBackColor = BackColor;
    }

    public Color AlternateBackColor { get; set; }

    protected override void OnDrawNode(DrawTreeNodeEventArgs e)
    {
        // background
        Color backColor = (GetTopNodeIndex(e.Node) & 1) == 0 ? BackColor : AlternateBackColor;
        using (Brush b = new SolidBrush(backColor))
        {
            e.Graphics.FillRectangle(b, new Rectangle(0, e.Bounds.Top, ClientSize.Width, e.Bounds.Height));
        }

        // icon
        if (e.Node.Nodes.Count > 0)
        {
            Image icon = GetIcon(e.Node.IsExpanded); // TODO: true=down;false:right
            e.Graphics.DrawImage(icon, e.Bounds.Left - icon.Width - 3, e.Bounds.Top);
        }

        // text (due to OwnerDrawText mode, indenting of e.Bounds will be correct)
        TextRenderer.DrawText(e.Graphics, e.Node.Text, Font, e.Bounds, ForeColor);

        // indicate selection (if not by backColor):
        if ((e.State & TreeNodeStates.Selected) != 0)
            ControlPaint.DrawFocusRectangle(e.Graphics, e.Bounds);
    }

    private int GetTopNodeIndex(TreeNode node)
    {
        while (node.Parent != null)
            node = node.Parent;

        return Nodes.IndexOf(node);
    }
}

To get the result similar to your screenshot just set the colors and you are done.

advancedTreeView1.BackColor = Color.DeepSkyBlue;
advancedTreeView1.AlternateBackColor = Color.LightBlue;