How to make rounded corners Winform using C#

This code shows how we can use make rounded corners form in our windows form application using c#.

public partial class frmLogin_roundedCorners : Form
    {
        public frmLogin_roundedCorners()
        {
            InitializeComponent();
        }

        private void panel1_Paint(object sender, PaintEventArgs e)
        {
            IntPtr ptr = NativeMethods.CreateRoundRectRgn(15, 15, this.Width, this.Height, 40, 40); // _BoarderRaduis can be adjusted to your needs, try 15 to start.
            this.Region = System.Drawing.Region.FromHrgn(ptr);
            NativeMethods.DeleteObject(ptr);
        }

        #region Make draggable

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

        private void panel1_MouseDown(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)
            {
                NativeMethods.ReleaseCapture();
                NativeMethods.SendMessage(Handle, WM_NCLBUTTONDOWN, HT_CAPTION, 0);
            }
        }

        #endregion
    }

    public class NativeMethods
    {
        [System.Runtime.InteropServices.DllImport("Gdi32.dll", EntryPoint = "CreateRoundRectRgn")]
        public static extern System.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
         );

        [System.Runtime.InteropServices.DllImport("gdi32.dll", EntryPoint = "DeleteObject")]
        public static extern bool DeleteObject(System.IntPtr hObject);
        [System.Runtime.InteropServices.DllImportAttribute("user32.dll")]
        public static extern bool ReleaseCapture();

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