Enabled设置为False时,前景色和背景色也不改变的TextBox 并居中

1.公共方法

    public class MyTextBox : TextBox
    {
        protected override void OnEnabledChanged(EventArgs e)
        {
            base.OnEnabledChanged(e);
            //设置Enabled为False时
            if (this.Enabled)
            {
                this.SetStyle(ControlStyles.UserPaint, false);
               
            }
            else
                this.SetStyle(ControlStyles.UserPaint, true);
            //再描绘
            this.Invalidate();
        }

        //描绘TextBox
        protected override void OnPaint(PaintEventArgs e)
        {
            base.OnPaint(e);
            System.Drawing.Brush b =
                new System.Drawing.SolidBrush(this.ForeColor);

            StringFormat sf = new StringFormat();
            sf.LineAlignment = StringAlignment.Center;
            sf.Alignment = StringAlignment.Center;
            //描绘字符串
            //e.Graphics.DrawString(this.Text, this.Font, b, -1, 1);
            e.Graphics.DrawString(this.Text, this.Font, b, this.ClientRectangle, sf);

            b.Dispose();
        }
    }

2.页面 designer.cs修改为 MyTextBox