A simple split button for C# WinForms

SplitButton.cs

using System;
using System.Windows.Forms;
using System.Drawing;

namespace SplitButton
{
    public class SplitButton : Button
    {
        public ContextMenuStrip SplitMenuStrip = new ContextMenuStrip() { ShowImageMargin = false };
        private string currentText;

        public SplitButton()
        {
            if (this.SplitMenuStrip.Items.Count > 0)
                this.Text = this.SplitMenuStrip.Items[0].Text;

            this.TextAlign = ContentAlignment.MiddleLeft;

            SplitMenuStrip.ItemClicked += SplitMenuStrip_ItemClicked;
        }

        private void SplitMenuStrip_ItemClicked(object sender, ToolStripItemClickedEventArgs e)
        {
            this.currentText = e.ClickedItem.Text;
            this.Text = this.currentText;
        }

        protected override void OnPaint(PaintEventArgs pevent)
        {
            if (string.IsNullOrEmpty(currentText))
            {
                if (this.SplitMenuStrip.Items.Count > 0)
                    this.Text = this.SplitMenuStrip.Items[0].Text;
            }
            else
                this.Text = currentText;

            base.OnPaint(pevent);

            Graphics g = pevent.Graphics;
            Rectangle bounds = ClientRectangle;

            Point middle = new Point(Convert.ToInt32(bounds.Left + bounds.Width - 10), Convert.ToInt32(bounds.Top + bounds.Height / 2));

            //if the width is odd - favor pushing it over one pixel right.
            middle.X += (bounds.Width % 2);

            Point[] arrow = new[] { new Point(middle.X - 2, middle.Y - 1), new Point(middle.X + 3, middle.Y - 1), new Point(middle.X, middle.Y + 2) };

            if (Enabled)
                g.FillPolygon(SystemBrushes.ControlText, arrow);
            else
                g.FillPolygon(SystemBrushes.ButtonShadow, arrow);
        }

        protected override void OnClick(EventArgs e)
        {
            SplitMenuStrip.Show(this, new Point(0, this.Height), ToolStripDropDownDirection.BelowRight);
        }
    }
}