program.cs:

  static class Program
    {
        [STAThread]
        static void Main( string[] args )
        {
            Application.EnableVisualStyles( );
            Application.SetCompatibleTextRenderingDefault( false );
            XnaControlGame.CreateAndShow<MainDialog, VoxelEditorGame>( );
        }
    }

XnaControlGame.cs:

 public interface IXnaFormContainer
    {
        Control XnaControl { get; }
        XnaControlGame Game { get; set; }
    }

    public abstract class XnaControlGame : Microsoft.Xna.Framework.Game
    {
        public Control Parent { get; private set; }

        public static void CreateAndShow<T, Q>( )
            where T : Form, IXnaFormContainer, new( )
            where Q : XnaControlGame
        {
            using ( T form = new T( ) )
            {
                form.Show( );

                using ( Q game = ( Q ) Activator.CreateInstance( typeof( Q ), new object[] { form.XnaControl.Handle, form, form.XnaControl } ) )
                {
                    form.Game = game;
                    game.Parent = form.XnaControl;
                    game.Run( );
                }
            }
        }


        #region Private Vars to Build Embedded Xna Control

        IntPtr _XnaDrawingSurface;
        GraphicsDeviceManager graphics;

        System.Windows.Forms.Form parentForm;
        System.Windows.Forms.Control controlXna;

        System.Windows.Forms.Control gameForm;

        #endregion

        #region Constructor

        public XnaControlGame( IntPtr handle,
            System.Windows.Forms.Form parentForm,
            System.Windows.Forms.Control surfaceControl )
        {
            graphics = new GraphicsDeviceManager( this );
            graphics.GraphicsProfile = GraphicsProfile.Reach;
            Content.RootDirectory = "Content";

            this.parentForm = parentForm;
            this.controlXna = surfaceControl;

            gameForm = System.Windows.Forms.Control.FromHandle( this.Window.Handle );
            gameForm.VisibleChanged += new EventHandler( gameForm_VisibleChanged );
            controlXna.SizeChanged += new EventHandler( pictureBox_SizeChanged );

            // preparing device settings handler.
            _XnaDrawingSurface = handle;
            Mouse.WindowHandle = handle;

            graphics.PreparingDeviceSettings += OnPreparingDeviceSettings;
            graphics.PreferredBackBufferWidth = (controlXna.Width > 0) ? controlXna.Width : 50;
            graphics.PreferredBackBufferHeight = (controlXna.Height > 0) ? controlXna.Height : 50;

            parentForm.FormClosed += delegate( object sender, System.Windows.Forms.FormClosedEventArgs e )
            {
                this.Exit( );
                Application.Exit( );
            };
        }

        #endregion

        #region Events

        private void OnPreparingDeviceSettings( object sender, PreparingDeviceSettingsEventArgs e )
        {
            e.GraphicsDeviceInformation.PresentationParameters.DeviceWindowHandle = _XnaDrawingSurface;
        }

        private void gameForm_VisibleChanged( object sender, EventArgs e )
        {
            if ( gameForm.Visible == true )
                gameForm.Visible = false;
        }

        void pictureBox_SizeChanged( object sender, EventArgs e )
        {
            if ( parentForm.WindowState !=
                System.Windows.Forms.FormWindowState.Minimized )
            {
                graphics.PreferredBackBufferWidth = controlXna.Width;
                graphics.PreferredBackBufferHeight = controlXna.Height;
                graphics.ApplyChanges( );
                OnSizeChanged( );
            }
        }

        protected virtual void OnSizeChanged( ) { }

        #endregion
    }