Ownerdrawn TreeView (WinForms)

Question

I have a TreeView control with checkboxes which is completely owner drawn (DrawMode = TreeViewDrawMode.OwnerDrawAll).

What I'm trying to do is to have the checkboxes owner drawn, so that they can have a grayed state. I'm using VisualStyleRenderer for this.

The problem arises when I have to correctly place the expand/collapse glyph and the checkbox in the item bounds, because the "hit-test areas" for both the glyph and the checkbox seems to be unknown and unchangeable.

Is there a way to get the bounds of those areas, or to replace the default ones with custom values?

Answer 1

I ran into the same problem. You have to offset your drawing by the proper amount, which is predictable.

There's probably more here than you need, but here's my drawing for a custom tree I used alongside a calendar control:

private void TreeViewControl_DrawNode(Object sender, DrawTreeNodeEventArgs e)
{
    //What might seem like strange positioning/offset is to ensure that our custom drawing falls in
    //  line with where the base drawing would appear.  Otherwise, click handlers (hit tests) fail 
    //  to register properly if our custom-drawn checkbox doesn't fall within the expected coordinates.

    Int32 boxSize = 16;
    Int32 offset = e.Node.Parent == null ? 3 : 21;
    Rectangle bounds = new Rectangle(new Point(e.Bounds.X + offset, e.Bounds.Y + 1), new Size(boxSize, boxSize));
    ControlPaint.DrawCheckBox(e.Graphics, bounds, e.Node.Checked ? ButtonState.Checked : ButtonState.Normal);
    if (e.Node.Parent != null)
    {
        Color c = Color.Black;
        String typeName = e.Node.Name.Remove(0, 4);
        Object o = Enum.Parse(typeof(CalendarDataProvider.CalendarDataItemType), typeName);
        if (o != null && (o is CalendarDataProvider.CalendarDataItemType))
            c = CalendarDataProvider.GetItemTypeColor((CalendarDataProvider.CalendarDataItemType)o);
        bounds = new Rectangle(new Point(bounds.X + boxSize + 2, e.Bounds.Y + 1), new Size(13, 13));
        using (SolidBrush b = new SolidBrush(c))
            e.Graphics.FillRectangle(b, bounds);
        e.Graphics.DrawRectangle(Pens.Black, bounds);
        e.Graphics.DrawLine(Pens.Black, new Point(bounds.X + 1, bounds.Bottom + 1), new Point(bounds.Right + 1, bounds.Bottom + 1));
        e.Graphics.DrawLine(Pens.Black, new Point(bounds.Right + 1, bounds.Y + 1), new Point(bounds.Right + 1, bounds.Bottom + 1));
    }
    Font font = new Font("Microsoft Sans Serif", 9f, e.Node.Parent == null ? FontStyle.Bold : FontStyle.Regular);
    bounds = new Rectangle(new Point(bounds.X + boxSize + 2, e.Bounds.Y), new Size(e.Bounds.Width - offset - 2, boxSize));
    e.Graphics.DrawString(e.Node.Text, font, Brushes.Black, bounds);
}