FormBorderStyle.None removes the native open effec

Question

I like to have my form borderless in C#. So I used this code:

FormBorderStyle = FormBorderStyle.None;

But it removes the aero effect of windows 8. The form opens suddenly like a blink.

How can i bring the aero effect back?

Answer 1

I am answering my own question using the C++ reference I wrote a class inherited from Form Class. Each form in application should be inherited from this class instead of Form Class.

 public class AeroForm : Form
 {
    int _w = 100, _h = 100;
    bool aero = false;

    [StructLayout(LayoutKind.Sequential)]
    struct MARGINS { public int Left, Right, Top, Bottom;  }

    [DllImport("dwmapi.dll", PreserveSig = false)]
    static extern void DwmExtendFrameIntoClientArea
                              (IntPtr hwnd, ref MARGINS margins);

    [DllImport("dwmapi.dll", PreserveSig = false)]
    static extern bool DwmIsCompositionEnabled();

    public AeroForm()
    {
            aero = IsCompositionEnabled();
        }

        public AeroForm(int width, int height)
            : this()
        {
            _w = width;
            _h = height;
            Size = new Size(width, height);
        }

        protected override void WndProc(ref Message m)
        {
            const int WM_NCCALCSIZE = 0x0083;
            switch (m.Msg)
            {
                case WM_NCCALCSIZE:
                    if (aero)
                        return;
                    break;
            }
            base.WndProc(ref m);
        }

        //this is for checking the OS's functionality.
        //Windows XP does not have dwmapi.dll
        //also, This corrupts the designer... 
        //so i used the Release/Debug configuration
        bool IsCompositionEnabled()
        {
    #if !DEBUG
            return File.Exists(Environment.SystemDirectory + "\\dwmapi.dll")
                 && DwmIsCompositionEnabled();
    #else
            return false;
    #endif
        }

        //this one is used for a shadow when aero is not available
        protected override CreateParams CreateParams
        {
            get
            {
                const int CS_DROPSHADOW = 0x00020000;
                const int WS_MINIMIZEBOX = 0x20000;
                const int CS_DBLCLKS = 0x8;
                CreateParams cp = base.CreateParams;
                if (!aero)
                    cp.ClassStyle |= CS_DROPSHADOW;
                cp.Style |= WS_MINIMIZEBOX;
                cp.ClassStyle |= CS_DBLCLKS;
                return cp;
            }
        }

        //this is for aero shadow and border configurations
        protected override void OnLoad(EventArgs e)
        {
            base.OnLoad(e);
            if (aero)
            {
                FormBorderStyle = FormBorderStyle.FixedSingle;
                ControlBox = false;
                MinimizeBox = false;
                MaximizeBox = false;
                Size = new Size(_w, _h);
                MARGINS _glassMargins = new MARGINS()
                {
                    Top = 5,
                    Left = 5,
                    Bottom = 5,
                    Right = 5
                };
                DwmExtendFrameIntoClientArea(this.Handle, ref _glassMargins);
            }
            else
                FormBorderStyle = FormBorderStyle.None;
        }

        //When you minimize and restore, the size will change.
        //this override is for preventing this unwanted resize.
        protected override void OnPaint(PaintEventArgs e)
        {
            if (aero)
                Size = new Size(_w, _h);
            base.OnPaint(e);
        }
    }

with Show() and Application.Run() it works great! but it has some regressions when the form opens with ShowDialog(). Closing the form, you will see a border that closes after your client content hides.