using System;
using System.Drawing;
using System.Windows.Forms;
using System.Drawing.Drawing2D;
using System.Runtime.InteropServices;


namespace WindowsFormsApplication3
{
    public partial class Form1 : Form
    {

        [DllImport("Gdi32.dll", EntryPoint = "CreateRoundRectRgn")]
        private static extern IntPtr CreateRoundRectRgn
        (
            int nLeftRect, // x-coordinate of upper-left corner
            int nTopRect, // y-coordinate of upper-left corner
            int nRightRect, // x-coordinate of lower-right corner
            int nBottomRect, // y-coordinate of lower-right corner
            int nWidthEllipse, // height of ellipse
            int nHeightEllipse // width of ellipse
         );

        public Form1()
        {
            InitializeComponent();
            Region = System.Drawing.Region.FromHrgn(CreateRoundRectRgn(0, 0, Width, Height, 5, 5));
        }

        protected override void OnLoad(EventArgs e)
        {
            base.OnLoad(e);
            this.FormBorderStyle = FormBorderStyle.None;
        }

        protected override void OnPaintBackground(PaintEventArgs e)
        {
            using (LinearGradientBrush brush = new LinearGradientBrush(this.ClientRectangle,
                                                                       Color.LawnGreen,
                                                                       Color.Green,
                                                                       90F))
            {
                e.Graphics.FillRectangle(brush, this.ClientRectangle);
            }
        }


        public const int WM_NCLBUTTONDOWN = 0xA1;
        public const int HT_CAPTION = 0x2;

        [System.Runtime.InteropServices.DllImportAttribute("user32.dll")]
        public static extern int SendMessage(IntPtr hWnd, int Msg, int wParam, int lParam);
        [System.Runtime.InteropServices.DllImportAttribute("user32.dll")]
        public static extern bool ReleaseCapture();

        private void Form1_Load(object sender, EventArgs e)
        {

        }

    private void Form1_MouseDown_1(object sender, MouseEventArgs e)
    {
        if (e.Button == MouseButtons.Left)
        {
            ReleaseCapture();
            SendMessage(Handle, WM_NCLBUTTONDOWN, HT_CAPTION, 0);
        }
        }

        private void button1_Click(object sender, EventArgs e)
        {
            this.Close();
        }
    }
}