Winfrom TextBox 添加水印文字 + 字体颜色

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

namespace KK.WaterMark.Control
{
    public partial class WaterMarkTextBox : TextBox
    {
        private string watermarkText;
        public string WatermarkText
        {
            get { return watermarkText; }
            set { watermarkText = value; }
        }
        private Color watermarkTextColor;
        public Color WatermarkTextColor
        {
            get { return watermarkTextColor; }
            set { watermarkTextColor = value; }
        }

        public WaterMarkTextBox()
        {
            InitializeComponent();
        }

        protected override void WndProc(ref Message m)
        {
            base.WndProc(ref m);

            if (m.Msg ==0x000F )//WM_PAINT
            {
                WmPaint(ref m);
            }
        }

        private void WmPaint(ref Message m)
        {
            Rectangle rectangle = new Rectangle(0, 0, Width, Height);
            using (Graphics graphics = Graphics.FromHwnd(base.Handle))
            {
                if (Text.Length == 0
                   && !string.IsNullOrEmpty(watermarkText)
                   && !Focused)
                {
                    TextFormatFlags format = TextFormatFlags.EndEllipsis
                        | TextFormatFlags.VerticalCenter;

                    if (RightToLeft == RightToLeft.Yes)
                    {
                        format |= TextFormatFlags.RightToLeft | TextFormatFlags.Right;
                    }

                    TextRenderer.DrawText(graphics, watermarkText, Font, 
                        base.ClientRectangle, watermarkTextColor, format);
                }
            }
        }
    }
}

运行效果如下所示：