Popup in winforms (but not registered as a new standalone window)

Question

I would like to display information messages on the screen, over my main form.

The problem I have is that I don't want this to be registered in windows as a new form, since this shows up in the taskbar when switching between apps. I have many of these info boxes popping up to notify you of events.

The idea is that it should work similar to a dialogbox (don't get registered as a standalone form) with the exception that it don't expect you to interact with the dialog.

So far I use the following:

var notification = new Notification();
notification.ShowInTaskbar = false;
notification.Show();

Can anyone please point out how you can prevent this window from being registered as a standalone window

EDIT: Thanks for the suggested link @shf301 : Best way to hide a window from the Alt-Tab program switcher?

I had a look at it but it's unrelated. The link explains how to hide an application from the alt-tab menu. In this example I don't want to hide my application, I simply want to show popups without them being registered as new windows.

possible duplicate of [Best way to hide a window from the Alt-Tab program switcher?](http://stackoverflow.com/questions/357076/best-way-to-hide-a-window-from-the-alt-tab-program-switcher) — shf301, May 03 '15 at 19:22
Possible duplicate of [Popup window in winform c#](https://stackoverflow.com/questions/16463599/popup-window-in-winform-c-sharp) — Sinatr, Mar 07 '19 at 15:53

score 2 · Answer 1 · answered May 03 '15 at 19:15

2

The only way that I know to show a window within a program (without it appearing in the taskbar) is to use a Multiple Document Interface (MDI). This is somewhat complicated but can do exactly the task you want: showing a window within a window.

More info on MDIs in .NET: http://csharp.net-informations.com/gui/cs-mdi-form.htm

answered May 03 '15 at 19:15

electroduck

21
1

Thanks, I'm aware of MDI windows but this is not an option in my case. – z0mbi3 May 03 '15 at 19:27

Philip Stuyck · Accepted Answer · 2015-05-03T19:33:56.300

This is not so easy because basically popups are not supported in windows forms. Although windows forms is based on win32 and in win32 popup are supported. If you accept a few tricks, following code will set you going with a popup. You decide if you want to put it to good use : (This is the way for instance tooltips are made)

class PopupWindow : Control
{
    private const int WM_ACTIVATE = 0x0006;
    private const int WM_MOUSEACTIVATE = 0x0021;

    private Control ownerControl;

    public PopupWindow(Control ownerControl)
        :base()
    {
        this.ownerControl = ownerControl;
        base.SetTopLevel(true);
    }

    public Control OwnerControl
    {
        get
        {
            return (this.ownerControl as Control);
        }
        set
        {
            this.ownerControl = value;
        }
    }

    protected override CreateParams CreateParams
    {
        get
        {
            CreateParams createParams = base.CreateParams;

            createParams.Style = WindowStyles.WS_POPUP |
                                 WindowStyles.WS_VISIBLE |
                                 WindowStyles.WS_CLIPSIBLINGS |
                                 WindowStyles.WS_CLIPCHILDREN |
                                 WindowStyles.WS_MAXIMIZEBOX |
                                 WindowStyles.WS_BORDER;
            createParams.ExStyle = WindowsExtendedStyles.WS_EX_LEFT |
                                   WindowsExtendedStyles.WS_EX_LTRREADING |
                                   WindowsExtendedStyles.WS_EX_RIGHTSCROLLBAR | 
                                   WindowsExtendedStyles.WS_EX_TOPMOST;

            createParams.Parent = (this.ownerControl != null) ? this.ownerControl.Handle : IntPtr.Zero;
            return createParams;
        }
    }

    [DllImport("user32.dll", CharSet = CharSet.Auto, ExactSpelling = true)]
    public static extern IntPtr SetActiveWindow(HandleRef hWnd);

    protected override void WndProc(ref Message m)
    {
        switch (m.Msg)
        {
            case WM_ACTIVATE:
                {
                    if ((int)m.WParam == 1)
                    {
                        //window is being activated
                        if (ownerControl != null)
                        {
                            SetActiveWindow(new HandleRef(this, ownerControl.FindForm().Handle));
                        }
                    }
                    break;
                }
            case WM_MOUSEACTIVATE:
                {
                    m.Result = new IntPtr(MouseActivate.MA_NOACTIVATE);
                    return;
                    //break;
                }
        }
        base.WndProc(ref m);
    }

    protected override void OnPaint(PaintEventArgs e)
    {
        base.OnPaint(e);
        e.Graphics.FillRectangle(SystemBrushes.Info, 0, 0, Width, Height);
        e.Graphics.DrawString((ownerControl as VerticalDateScrollBar).FirstVisibleDate.ToLongDateString(), this.Font, SystemBrushes.InfoText, 2, 2);
    }
}

Experiment with it a bit, you have to play around with its position and its size. Use it wrong and nothing shows.

Thanks Philip for the quick and excellent answer. Anyone who uses it .. please see my post below for additional code. — z0mbi3, May 03 '15 at 19:55

score 1 · Answer 3 · answered May 03 '15 at 19:52

@Philip's answer is correct.

I had to add the following:

    internal class WindowsExtendedStyles
    {

        public const int WS_EX_DLGMODALFRAME = 0x00000001;

        public const int WS_EX_NOPARENTNOTIFY = 0x00000004;

        public const int WS_EX_TOPMOST = 0x00000008;

        public const int WS_EX_ACCEPTFILES = 0x00000010;

        public const int WS_EX_TRANSPARENT = 0x00000020;

        public const int WS_EX_MDICHILD = 0x00000040;

        public const int WS_EX_TOOLWINDOW = 0x00000080;

        public const int WS_EX_WINDOWEDGE = 0x00000100;

        public const int WS_EX_CLIENTEDGE = 0x00000200;

        public const int WS_EX_CONTEXTHELP = 0x00000400;

        public const int WS_EX_RIGHT = 0x00001000;

        public const int WS_EX_LEFT = 0x00000000;

        public const int WS_EX_RTLREADING = 0x00002000;

        public const int WS_EX_LTRREADING = 0x00000000;

        public const int WS_EX_LEFTSCROLLBAR = 0x00004000;

        public const int WS_EX_RIGHTSCROLLBAR = 0x00000000;

        public const int WS_EX_CONTROLPARENT = 0x00010000;

        public const int WS_EX_STATICEDGE = 0x00020000;

        public const int WS_EX_APPWINDOW = 0x00040000;

        public const int WS_EX_OVERLAPPEDWINDOW = WS_EX_WINDOWEDGE | WS_EX_CLIENTEDGE;

        public const int WS_EX_PALETTEWINDOW = WS_EX_WINDOWEDGE | WS_EX_TOOLWINDOW | WS_EX_TOPMOST;

        public const int WS_EX_LAYERED = 0x00080000;

        public const int WS_EX_NOINHERITLAYOUT = 0x00100000; // Disable inheritence of mirroring by children

        public const int WS_EX_LAYOUTRTL = 0x00400000; // Right to left mirroring

        public const int WS_EX_COMPOSITED = 0x02000000;

        public const int WS_EX_NOACTIVATE = 0x08000000;

    }

    internal class MouseActivate
    {

        public const int MA_ACTIVATE = 1;

        public const int MA_ACTIVATEANDEAT = 2;

        public const int MA_NOACTIVATE = 3;

        public const int MA_NOACTIVATEANDEAT = 4;

    }

score 0 · Answer 4 · answered May 03 '15 at 19:24

If this notifications you are looking for need to support user interaction, you may consider showing a popup using the ToolStripDrownDown control and hosting a control in it by the ToolStripControlHost.

Or of they are just supposed to display information, with no user interaction, use a Tooltip (with Balloon = true) control. You may also customize it's visuals by custom drawing it's content.

Popup in winforms (but not registered as a new standalone window)

4 Answers4

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