Hook to detect Minimize Window C#

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Hi all How can I detect in C # that the user clicked on the minimize button of an external program (eg notepad)? Thanks

This should work:

    public class myClass
    [return: MarshalAs(UnmanagedType.Bool)]
    static extern bool GetWindowPlacement(IntPtr hWnd, ref WINDOWPLACEMENT lpwndpl);

    const UInt32 SW_HIDE =         0;
    const UInt32 SW_SHOWNORMAL =       1;
    const UInt32 SW_NORMAL =       1;
    const UInt32 SW_SHOWMINIMIZED =    2;
    const UInt32 SW_SHOWMAXIMIZED =    3;
    const UInt32 SW_MAXIMIZE =     3;
    const UInt32 SW_SHOWNOACTIVATE =   4;
    const UInt32 SW_SHOW =         5;
    const UInt32 SW_MINIMIZE =     6;
    const UInt32 SW_SHOWMINNOACTIVE =  7;
    const UInt32 SW_SHOWNA =       8;
    const UInt32 SW_RESTORE =      9;

    public myClass()
        var proc = Process.GetProcessesByName("notepad");
        if (proc.Length > 0)
            bool isNotepadMinimized = myClass.GetMinimized(proc[0].MainWindowHandle);

            if (isNotepadMinimized)
                Console.WriteLine("Notepad is Minimized!");

    private struct WINDOWPLACEMENT
        public int length;
        public int flags;
        public int showCmd;
        public System.Drawing.Point ptMinPosition;
        public System.Drawing.Point ptMaxPosition;
        public System.Drawing.Rectangle rcNormalPosition;

    public static bool GetMinimized(IntPtr handle)
        placement.length = Marshal.SizeOf(placement);
        GetWindowPlacement(handle, ref placement);
        return placement.flags == SW_SHOWMINIMIZED;

Edit: Just re-read you question and noticed you wanted to be notified when Notepad get minimized. Well you could use the code above in a timer to poll the status change.

How to detect when a windows form is being minimized?, To get in before the form has been minimised you'll have to hook into the WndProc procedure: private const int WM_SYSCOMMAND = 0x0112;  Detect Window Minimize and Maximize. C# / C Sharp Forums on Bytes. By using this site, hook that will let me detect when any window is minimized or restored?

As Hans Passant said you cannot get the event of it being minimized.

Although, I believe you can store the states of windows and see if they are minimized at a later interval. by using the GetWindowPlacement Function.

[Solved] Getting external application minimize and maximize events , An ultimate way of doing such thing is using the global Windows Hook. Please see my recent answer: Windows Forms and Word Automation[^]. 1- Create a C# Console Application. Create a simple console application and name it as you wish. This console application should target the .Net framework. 2- Add The Mouse Global Hooks nuget package. Add this package to your solution; MouseKeyHook. 3- Add a Reference to System.Windows.Forms assembly. You will need to handle click events.

The answer above has an error.

You need to check placement.showCMD, not placement.flags

placement.length = Marshal.SizeOf(placement);
GetWindowPlacement(_hwnd, ref placement);
return placement.showCmd == SW_SHOWMINIMIZED;

Please see https://msdn.microsoft.com/en-us/library/windows/desktop/ms632611(v=vs.85).aspx

How to wrice code in minimize button click event in c# .net windows , To detect the Minimize operation, implement a SizeChanged event handler and check the WindowState property. For the closing operation,  A hook is a point in the system message-handling mechanism where an application can install a subroutine to monitor the message traffic in the system and process certain types of messages before they reach the target window procedure.

Handle minimized, maximized, restore event of Form in c#, private void form1_sizeeventhandler(object sender, EventArgs e). {. if (this.​WindowState == FormWindowState.Minimized). {. MessageBox. i need to use either the EVENT_SYSTEM_MINIMIZESTART or EVENT_SYSTEM_MINIMIZEEND event constant to receive notification of window objects being minimized. i Used the eventMin and eventMax parameters of the SetWinEventHook function to indicate that i am interested in receiving notifications for one of these events and EVENT_SYSTEM_FOREGROUND.

event hooks and blocking min/max/restore/close, One thing that event hooks can do is detect when a window is being Is it possible to catch the close button and minimize the window instead? If a 64-bit application installs a global hook on 64-bit Windows, the 64-bit hook is injected into each 64-bit process, while all 32-bit processes use a callback to the hooking application.

Form.WindowState Property (System.Windows.Forms), Gets or sets a value that indicates whether form is minimized, maximized, or normal. WM_SYSCOMMAND message. 05/31/2018; 3 minutes to read; In this article. A window receives this message when the user chooses a command from the Window menu (formerly known as the system or control menu) or when the user chooses the maximize button, minimize button, restore button, or close button.

  • That requires injecting a DLL into the process with SetWindowsHookEx(). You can't write such a DLL in managed code.