QQ圆形头像框的绘制

GDI重绘 无边框窗体的拖动（FormBorderStyle=none以后窗体是无法拖动的）

  private Point mouseOff;//鼠标移动位置变量
        private bool leftFlag;//鼠标是否为左键
        /// <summary>
        /// 圆形图像框的绘制
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void pictureBox3_Paint(object sender, PaintEventArgs e)
        {
            GraphicsPath gp = new GraphicsPath();
            gp.AddEllipse(pictureBox3.ClientRectangle);
            Region region = new Region(gp);
            pictureBox3.Region = region;
            gp.Dispose();
            region.Dispose();        }
        /// <summary>
        /// 关闭
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void pictureBox4_Click(object sender, EventArgs e)
        {
            this.Close();
        }        private void pictureBox4_MouseEnter(object sender, EventArgs e)
        {
            if (Convert.ToInt16(pictureBox4.Tag) == 0)
            {
                pictureBox4.Image = Properties.Resources.btn_close_highlight;
              
            }