鼠标拖拽图像

       bool flag=false; 
　　　　private void pictureBox1_MouseEnter(object sender, EventArgs e)
        {
            flag = true;
        }

        private void Form1_MouseMove(object sender, MouseEventArgs e)
        {
            if (flag)
                pictureBox1.Location = new System.Drawing.Point(e.X,e.Y);
        }