private void label1_Paint(object sender, PaintEventArgs e)
    {
        if (sender is not Label lbl) return;

        DrawBorder(lbl, e.Graphics, Color.White, Color.Gray, Color.Gray, lbl.Width, lbl.Height);
    }


    /// <summary>绘制边框</summary>
    /// <param name="lbl"></param>
    /// <param name="g"></param>
    /// <param name="backcolor">lable前景颜色</param>
    /// <param name="backcolor">lable背景颜色</param>
    /// <param name="bordercolor">边框颜色</param>
    /// <param name="x">label宽度</param>
    /// <param name="y">label高度</param>
    private void DrawBorder(Label lbl, System.Drawing.Graphics g, Color forecolor, Color backcolor, Color bordercolor, int x, int y)
    {
        using var SegBrush = new SolidBrush(backcolor);
        using Pen pen = new Pen(SegBrush, 1);

        lbl.BorderStyle = BorderStyle.None;
        lbl.BackColor = backcolor;

        pen.Color = forecolor;

        Rectangle myRectangle = new Rectangle(0, 0, x, y);
        //画个边框
        ControlPaint.DrawBorder(g, myRectangle, bordercolor, ButtonBorderStyle.Solid);
    }