Question

How do you change that ugly blue color that you get when you select something in a listbox in Windows Forms? All of the solutions I was able to find either include re-creating the whole control, or just using WPF. Is there any way to do it within WinForms?

Answer 1

Set DrawMode of your listBox to OwnerDrawFixed and subscribe to DrawItem event:

private void listBox_DrawItem(object sender, DrawItemEventArgs e)
{
    e.DrawBackground();
    Graphics g = e.Graphics;
    Brush brush = ((e.State & DrawItemState.Selected) == DrawItemState.Selected) ? 
                  Brushes.Red : new SolidBrush(e.BackColor);
    g.FillRectangle(brush, e.Bounds);
    e.Graphics.DrawString(listBox.Items[e.Index].ToString(), e.Font, 
             new SolidBrush(e.ForeColor), e.Bounds, StringFormat.GenericDefault); 
    e.DrawFocusRectangle();            
}

You can determine state of drawing item by checking e.State property of event argument. If state is Selected, then use whatever brush you like (e.g. Red) to fill item line.