I'm creating an app that needs UI but not show up inside the taskbar, I know exactly how to do this in, winforms and wpf, but the window object doesn't contain a ShowInTaskBar variable that I can just change.
I have tried NotifyIcon but that doesn't hide it from the taskbar, I also can't find any documentation on if this is even possible.
I only create a stack overflow question when I've spent more than 5 hours on this, so any help would be appreciated.
Nick showed me this post https://stackoverflow.com/a/551847/14724147
Just add the window handle to the win32 api and it will hide it from alt+tab and the taskbar
public MainWindow()
{
InitializeComponent();
IntPtr hWnd = WindowNative.GetWindowHandle(this);
int exStyle = (int)GetWindowLong(hWnd, (int)GetWindowLongFields.GWL_EXSTYLE);
exStyle |= (int)ExtendedWindowStyles.WS_EX_TOOLWINDOW;
SetWindowLong(hWnd, (int)GetWindowLongFields.GWL_EXSTYLE, (IntPtr)exStyle);
}
#region Window styles
[Flags]
public enum ExtendedWindowStyles
{
// ...
WS_EX_TOOLWINDOW = 0x00000080,
// ...
}
public enum GetWindowLongFields
{
// ...
GWL_EXSTYLE = (-20),
// ...
}
[DllImport("user32.dll")]
public static extern IntPtr GetWindowLong(IntPtr hWnd, int nIndex);
public static IntPtr SetWindowLong(IntPtr hWnd, int nIndex, IntPtr dwNewLong)
{
int error = 0;
IntPtr result = IntPtr.Zero;
// Win32 SetWindowLong doesn't clear error on success
SetLastError(0);
if (IntPtr.Size == 4)
{
// use SetWindowLong
Int32 tempResult = IntSetWindowLong(hWnd, nIndex, IntPtrToInt32(dwNewLong));
error = Marshal.GetLastWin32Error();
result = new IntPtr(tempResult);
}
else
{
// use SetWindowLongPtr
result = IntSetWindowLongPtr(hWnd, nIndex, dwNewLong);
error = Marshal.GetLastWin32Error();
}
if ((result == IntPtr.Zero) && (error != 0))
{
throw new System.ComponentModel.Win32Exception(error);
}
return result;
}
[DllImport("user32.dll", EntryPoint = "SetWindowLongPtr", SetLastError = true)]
private static extern IntPtr IntSetWindowLongPtr(IntPtr hWnd, int nIndex, IntPtr dwNewLong);
[DllImport("user32.dll", EntryPoint = "SetWindowLong", SetLastError = true)]
private static extern Int32 IntSetWindowLong(IntPtr hWnd, int nIndex, Int32 dwNewLong);
private static int IntPtrToInt32(IntPtr intPtr)
{
return unchecked((int)intPtr.ToInt64());
}
[DllImport("kernel32.dll", EntryPoint = "SetLastError")]
public static extern void SetLastError(int dwErrorCode);
#endregion
In my application I need to know when the user switches the virtual Desktop, e.g. by pressing Ctrl+Win+→.
I though it'd be a great idea to do this via Hooking. I have listed an example class I wrote to test my idea. I thought when the virtual Desktop changes, I would get a callback. However, there is no callback no matter how I change the virtual Desktop.
I also wrote a test application that creates, opens, switches and closes Desktops. It works fine, but my code below detects none of the Desktop switches.
public class SwitchDesktopMonitor
{
private delegate void CreateHookDelegate();
private delegate void SetWinEventHookCallback(IntPtr hWinEventHook, uint eventType, IntPtr hWnd, uint objectId, int childId, uint dwEventThread, uint dwmsEventTime);
[DllImport("user32.dll")]
private static extern IntPtr SetWinEventHook(uint eventMin, uint eventMax, IntPtr hmodWinEventProc, SetWinEventHookCallback lpfnWinEventProc, uint idProcess, uint idThread, uint dwFlags);
[DllImport("user32.dll")]
private static extern bool UnhookWinEvent(IntPtr hWinEventHook);
[DllImport("user32.dll", SetLastError = true)]
private static extern uint GetWindowThreadProcessId(IntPtr hWnd, out uint processId);
private IntPtr _setWinEventHook;
private readonly SetWinEventHookCallback _hookingCallback;
private readonly Window _window;
public SwitchDesktopMonitor(Window window)
{
_window = window;
_hookingCallback = (hWinEventHook, eventType, hWnd, objectId, childId, dwEventThread, dwmsEventTime) =>
{
Console.WriteLine("-> _hookingCallback - hWinEventHook = {0}, eventType = {1}, hWnd = {2}, objectId = {3}, childId = {4}, dwEventThread = {5}, dwmsEventTime = {6}",
hWinEventHook, eventType, hWnd, objectId, childId, dwEventThread, dwmsEventTime);
};
}
public void Start()
{
Console.WriteLine("{0}.Start", this);
if (_window == null || _window.Dispatcher == null)
{
return;
}
if (_window.Dispatcher.CheckAccess())
{
CreateHook();
}
else
{
_window.Dispatcher.Invoke(new CreateHookDelegate(CreateHook));
}
}
public void Stop()
{
Console.WriteLine("{0}.Stop", this);
if (_setWinEventHook != null)
{
Console.WriteLine("\tUnhookWinEvent = {0}", UnhookWinEvent(_setWinEventHook));
}
}
private void CreateHook()
{
var windowHandle = new WindowInteropHelper(_window).Handle;
uint processId;
uint threadId = GetWindowThreadProcessId(windowHandle, out processId);
Console.WriteLine("\twindowHandle = {0}, processId = {1}, threadId = {2}", windowHandle, processId, threadId);
_setWinEventHook = SetWinEventHook(0x0020, 0x0020, IntPtr.Zero, _hookingCallback, processId, threadId, 0x0000);
Console.WriteLine("\t_setWinEventHook = {0}", _setWinEventHook);
}
}
I don't have to do this way. I am thankful or other approaches. The only important thing is that I need to detect Windows Desktop switches.
You install a hook for the event EVENT_SYSTEM_DESKTOPSWITCH (0x0020). However, the term desktop here does not refer to "virtual desktops" as a feature in Windows 10 to switch between different sets of windows, but to desktops as a system concept in Windows to separate different operating environments (Normal, Logon, Screensaver).
So, you cannot detect a switching of virtual desktops this way.
Instead, use the way as shown in this open source library https://github.com/Grabacr07/VirtualDesktop which uses a currently undocumented VirtualDesktopNotificationService COM service in the Windows Shell to be notified when the current virtual desktop changes.
I've got an always on-top application (basically a status display) that I want to follow around another program and always sit just to the left of the minimize button.
I can get the Rect representing the "target" process using the following code which I can then pair with an offset to generate the initial position of my overlay.
Get the HWnd IntPtr:
private IntPtr HWnd = Process.GetProcessesByName("targetapplication")[0].MainWindowHandle;
Declare the function from user32.dll:
[DllImport("user32.dll", SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
private static extern bool GetWindowRect(IntPtr hWnd, ref RECT lpRect);
And the appropriate struct:
[StructLayout(LayoutKind.Sequential)]
private struct RECT
{
public int Left;
public int Top;
public int Right;
public int Bottom;
}
And then call it on demand.
However, I would like to avoid constantly polling this value, so I would like to hook into the target application and respond whenever the target window is moved.
Looking around the user32.dll documentation, the only way I can see for doing this is using SetWindowsHookEx(). I'm not entirely sure of how I'd go about intercepting an event from here however.
I believe the target application is built off of WinForms but I cannot be sure. So solutions that let me respond to the target's Move event or directly to some Windows Message would both be useful.
Any ideas on how I can proceed?
A method to hook a Windows Form to another process (Notepad, in this case) and follow the movements of the process' Main Window, to create sort of a Toolbar that can interact with the process, using SetWinEventHook().
To get the hooked Window bounds, GetWindowRect() is not recommended. Better call DwmGetWindowAttribute() passing DWMWA_EXTENDED_FRAME_BOUNDS as the DWMWINDOWATTRIBUTE, which still returns a RECT. This because GetWindowRect() is not DpiAware and it may return a virtualized measure in some contexts, plus it includes the Window drop shadow in specific configurations.
Read more about DpiAwarenes, Screen layout and VirtualScreen here:
Using SetWindowPos with multiple monitors
Also refactored the Hook helper class and the NativeMethods declarations.
▶ To move to foreground the Tool Window, as in the animation, when the hooked Window becomes the Foreground Window, also hook the EVENT_SYSTEM_FOREGROUND event: you'll receive a notification when the Foreground Window changes, then compare with the handle of Window you're hooking.
A visual representation of the results:
The Form class initialization procedure:
using System.Diagnostics;
using System.Drawing;
using System.Linq;
using System.Runtime.InteropServices;
using System.Windows.Forms;
public partial class Form1 : Form
{
private IntPtr notepadhWnd;
private IntPtr hWinEventHook;
private Process targetProc = null;
protected Hook.WinEventDelegate WinEventDelegate;
static GCHandle GCSafetyHandle;
public Form1()
{
InitializeComponent();
WinEventDelegate = new Hook.WinEventDelegate(WinEventCallback);
GCSafetyHandle = GCHandle.Alloc(WinEventDelegate);
targetProc = Process.GetProcessesByName("notepad").FirstOrDefault(p => p != null);
try {
if (targetProc != null) {
notepadhWnd = targetProc.MainWindowHandle;
if (notepadhWnd != IntPtr.Zero) {
uint targetThreadId = Hook.GetWindowThread(notepadhWnd);
hWinEventHook = Hook.WinEventHookOne(
NativeMethods.SWEH_Events.EVENT_OBJECT_LOCATIONCHANGE,
WinEventDelegate, (uint)targetProc.Id, targetThreadId);
var rect = Hook.GetWindowRectangle(notepadhWnd);
// Of course, set the Form.StartPosition to Manual
Location = new Point(rect.Right, rect.Top);
}
}
}
catch (Exception ex) {
// Log and message or
throw;
}
}
protected void WinEventCallback(
IntPtr hWinEventHook,
NativeMethods.SWEH_Events eventType,
IntPtr hWnd,
NativeMethods.SWEH_ObjectId idObject,
long idChild, uint dwEventThread, uint dwmsEventTime)
{
if (hWnd == notepadhWnd &&
eventType == NativeMethods.SWEH_Events.EVENT_OBJECT_LOCATIONCHANGE &&
idObject == (NativeMethods.SWEH_ObjectId)NativeMethods.SWEH_CHILDID_SELF)
{
var rect = Hook.GetWindowRectangle(hWnd);
Location = new Point(rect.Right, rect.Top);
}
}
protected override void OnFormClosing(FormClosingEventArgs e)
{
base.OnFormClosing(e);
if (!e.Cancel) {
if (GCSafetyHandle.IsAllocated) GCSafetyHandle.Free();
Hook.WinEventUnhook(hWinEventHook);
}
}
protected override void OnShown(EventArgs e)
{
if (targetProc == null) {
this.Hide();
MessageBox.Show("Notepad not found!", "Target Missing", MessageBoxButtons.OK, MessageBoxIcon.Hand);
this.Close();
}
else {
Size = new Size(50, 140);
targetProc.Dispose();
}
base.OnShown(e);
}
The support classes used to reference the Windows API methods:
using System.Runtime.InteropServices;
using System.Security.Permissions;
public class Hook
{
public delegate void WinEventDelegate(
IntPtr hWinEventHook,
NativeMethods.SWEH_Events eventType,
IntPtr hwnd,
NativeMethods.SWEH_ObjectId idObject,
long idChild,
uint dwEventThread,
uint dwmsEventTime
);
public static IntPtr WinEventHookRange(
NativeMethods.SWEH_Events eventFrom, NativeMethods.SWEH_Events eventTo,
WinEventDelegate eventDelegate,
uint idProcess, uint idThread)
{
return NativeMethods.SetWinEventHook(
eventFrom, eventTo,
IntPtr.Zero, eventDelegate,
idProcess, idThread,
NativeMethods.WinEventHookInternalFlags);
}
public static IntPtr WinEventHookOne(
NativeMethods.SWEH_Events eventId,
WinEventDelegate eventDelegate,
uint idProcess,
uint idThread)
{
return NativeMethods.SetWinEventHook(
eventId, eventId,
IntPtr.Zero, eventDelegate,
idProcess, idThread,
NativeMethods.WinEventHookInternalFlags);
}
public static bool WinEventUnhook(IntPtr hWinEventHook) =>
NativeMethods.UnhookWinEvent(hWinEventHook);
public static uint GetWindowThread(IntPtr hWnd)
{
return NativeMethods.GetWindowThreadProcessId(hWnd, IntPtr.Zero);
}
public static NativeMethods.RECT GetWindowRectangle(IntPtr hWnd)
{
NativeMethods.DwmGetWindowAttribute(hWnd,
NativeMethods.DWMWINDOWATTRIBUTE.DWMWA_EXTENDED_FRAME_BOUNDS,
out NativeMethods.RECT rect, Marshal.SizeOf<NativeMethods.RECT>());
return rect;
}
}
public static class NativeMethods
{
[StructLayout(LayoutKind.Sequential)]
public struct RECT
{
public int Left;
public int Top;
public int Right;
public int Bottom;
public Rectangle ToRectangle() => Rectangle.FromLTRB(Left, Top, Right, Bottom);
}
public static long SWEH_CHILDID_SELF = 0;
//SetWinEventHook() flags
public enum SWEH_dwFlags : uint
{
WINEVENT_OUTOFCONTEXT = 0x0000, // Events are ASYNC
WINEVENT_SKIPOWNTHREAD = 0x0001, // Don't call back for events on installer's thread
WINEVENT_SKIPOWNPROCESS = 0x0002, // Don't call back for events on installer's process
WINEVENT_INCONTEXT = 0x0004 // Events are SYNC, this causes your dll to be injected into every process
}
//SetWinEventHook() events
public enum SWEH_Events : uint
{
EVENT_MIN = 0x00000001,
EVENT_MAX = 0x7FFFFFFF,
EVENT_SYSTEM_SOUND = 0x0001,
EVENT_SYSTEM_ALERT = 0x0002,
EVENT_SYSTEM_FOREGROUND = 0x0003,
EVENT_SYSTEM_MENUSTART = 0x0004,
EVENT_SYSTEM_MENUEND = 0x0005,
EVENT_SYSTEM_MENUPOPUPSTART = 0x0006,
EVENT_SYSTEM_MENUPOPUPEND = 0x0007,
EVENT_SYSTEM_CAPTURESTART = 0x0008,
EVENT_SYSTEM_CAPTUREEND = 0x0009,
EVENT_SYSTEM_MOVESIZESTART = 0x000A,
EVENT_SYSTEM_MOVESIZEEND = 0x000B,
EVENT_SYSTEM_CONTEXTHELPSTART = 0x000C,
EVENT_SYSTEM_CONTEXTHELPEND = 0x000D,
EVENT_SYSTEM_DRAGDROPSTART = 0x000E,
EVENT_SYSTEM_DRAGDROPEND = 0x000F,
EVENT_SYSTEM_DIALOGSTART = 0x0010,
EVENT_SYSTEM_DIALOGEND = 0x0011,
EVENT_SYSTEM_SCROLLINGSTART = 0x0012,
EVENT_SYSTEM_SCROLLINGEND = 0x0013,
EVENT_SYSTEM_SWITCHSTART = 0x0014,
EVENT_SYSTEM_SWITCHEND = 0x0015,
EVENT_SYSTEM_MINIMIZESTART = 0x0016,
EVENT_SYSTEM_MINIMIZEEND = 0x0017,
EVENT_SYSTEM_DESKTOPSWITCH = 0x0020,
EVENT_SYSTEM_END = 0x00FF,
EVENT_OEM_DEFINED_START = 0x0101,
EVENT_OEM_DEFINED_END = 0x01FF,
EVENT_UIA_EVENTID_START = 0x4E00,
EVENT_UIA_EVENTID_END = 0x4EFF,
EVENT_UIA_PROPID_START = 0x7500,
EVENT_UIA_PROPID_END = 0x75FF,
EVENT_CONSOLE_CARET = 0x4001,
EVENT_CONSOLE_UPDATE_REGION = 0x4002,
EVENT_CONSOLE_UPDATE_SIMPLE = 0x4003,
EVENT_CONSOLE_UPDATE_SCROLL = 0x4004,
EVENT_CONSOLE_LAYOUT = 0x4005,
EVENT_CONSOLE_START_APPLICATION = 0x4006,
EVENT_CONSOLE_END_APPLICATION = 0x4007,
EVENT_CONSOLE_END = 0x40FF,
EVENT_OBJECT_CREATE = 0x8000, // hwnd ID idChild is created item
EVENT_OBJECT_DESTROY = 0x8001, // hwnd ID idChild is destroyed item
EVENT_OBJECT_SHOW = 0x8002, // hwnd ID idChild is shown item
EVENT_OBJECT_HIDE = 0x8003, // hwnd ID idChild is hidden item
EVENT_OBJECT_REORDER = 0x8004, // hwnd ID idChild is parent of zordering children
EVENT_OBJECT_FOCUS = 0x8005, // hwnd ID idChild is focused item
EVENT_OBJECT_SELECTION = 0x8006, // hwnd ID idChild is selected item (if only one), or idChild is OBJID_WINDOW if complex
EVENT_OBJECT_SELECTIONADD = 0x8007, // hwnd ID idChild is item added
EVENT_OBJECT_SELECTIONREMOVE = 0x8008, // hwnd ID idChild is item removed
EVENT_OBJECT_SELECTIONWITHIN = 0x8009, // hwnd ID idChild is parent of changed selected items
EVENT_OBJECT_STATECHANGE = 0x800A, // hwnd ID idChild is item w/ state change
EVENT_OBJECT_LOCATIONCHANGE = 0x800B, // hwnd ID idChild is moved/sized item
EVENT_OBJECT_NAMECHANGE = 0x800C, // hwnd ID idChild is item w/ name change
EVENT_OBJECT_DESCRIPTIONCHANGE = 0x800D, // hwnd ID idChild is item w/ desc change
EVENT_OBJECT_VALUECHANGE = 0x800E, // hwnd ID idChild is item w/ value change
EVENT_OBJECT_PARENTCHANGE = 0x800F, // hwnd ID idChild is item w/ new parent
EVENT_OBJECT_HELPCHANGE = 0x8010, // hwnd ID idChild is item w/ help change
EVENT_OBJECT_DEFACTIONCHANGE = 0x8011, // hwnd ID idChild is item w/ def action change
EVENT_OBJECT_ACCELERATORCHANGE = 0x8012, // hwnd ID idChild is item w/ keybd accel change
EVENT_OBJECT_INVOKED = 0x8013, // hwnd ID idChild is item invoked
EVENT_OBJECT_TEXTSELECTIONCHANGED = 0x8014, // hwnd ID idChild is item w? test selection change
EVENT_OBJECT_CONTENTSCROLLED = 0x8015,
EVENT_SYSTEM_ARRANGMENTPREVIEW = 0x8016,
EVENT_OBJECT_END = 0x80FF,
EVENT_AIA_START = 0xA000,
EVENT_AIA_END = 0xAFFF
}
//SetWinEventHook() Object Ids
public enum SWEH_ObjectId : long
{
OBJID_WINDOW = 0x00000000,
OBJID_SYSMENU = 0xFFFFFFFF,
OBJID_TITLEBAR = 0xFFFFFFFE,
OBJID_MENU = 0xFFFFFFFD,
OBJID_CLIENT = 0xFFFFFFFC,
OBJID_VSCROLL = 0xFFFFFFFB,
OBJID_HSCROLL = 0xFFFFFFFA,
OBJID_SIZEGRIP = 0xFFFFFFF9,
OBJID_CARET = 0xFFFFFFF8,
OBJID_CURSOR = 0xFFFFFFF7,
OBJID_ALERT = 0xFFFFFFF6,
OBJID_SOUND = 0xFFFFFFF5,
OBJID_QUERYCLASSNAMEIDX = 0xFFFFFFF4,
OBJID_NATIVEOM = 0xFFFFFFF0
}
public enum DWMWINDOWATTRIBUTE : uint
{
DWMWA_NCRENDERING_ENABLED = 1, // [get] Is non-client rendering enabled/disabled
DWMWA_NCRENDERING_POLICY, // [set] DWMNCRENDERINGPOLICY - Non-client rendering policy - Enable or disable non-client rendering
DWMWA_TRANSITIONS_FORCEDISABLED, // [set] Potentially enable/forcibly disable transitions
DWMWA_ALLOW_NCPAINT, // [set] Allow contents rendered In the non-client area To be visible On the DWM-drawn frame.
DWMWA_CAPTION_BUTTON_BOUNDS, // [get] Bounds Of the caption button area In window-relative space.
DWMWA_NONCLIENT_RTL_LAYOUT, // [set] Is non-client content RTL mirrored
DWMWA_FORCE_ICONIC_REPRESENTATION, // [set] Force this window To display iconic thumbnails.
DWMWA_FLIP3D_POLICY, // [set] Designates how Flip3D will treat the window.
DWMWA_EXTENDED_FRAME_BOUNDS, // [get] Gets the extended frame bounds rectangle In screen space
DWMWA_HAS_ICONIC_BITMAP, // [set] Indicates an available bitmap When there Is no better thumbnail representation.
DWMWA_DISALLOW_PEEK, // [set] Don't invoke Peek on the window.
DWMWA_EXCLUDED_FROM_PEEK, // [set] LivePreview exclusion information
DWMWA_CLOAK, // [set] Cloak Or uncloak the window
DWMWA_CLOAKED, // [get] Gets the cloaked state Of the window. Returns a DWMCLOACKEDREASON object
DWMWA_FREEZE_REPRESENTATION, // [set] BOOL, Force this window To freeze the thumbnail without live update
PlaceHolder1,
PlaceHolder2,
PlaceHolder3,
DWMWA_ACCENTPOLICY = 19
}
public static SWEH_dwFlags WinEventHookInternalFlags =
SWEH_dwFlags.WINEVENT_OUTOFCONTEXT |
SWEH_dwFlags.WINEVENT_SKIPOWNPROCESS |
SWEH_dwFlags.WINEVENT_SKIPOWNTHREAD;
[DllImport("dwmapi.dll", SetLastError = true)]
internal static extern int DwmGetWindowAttribute(IntPtr hwnd, DWMWINDOWATTRIBUTE dwAttribute, out RECT pvAttribute, int cbAttribute);
[DllImport("user32.dll", SetLastError = true)]
internal static extern uint GetWindowThreadProcessId(IntPtr hWnd, out uint lpdwProcessId);
[DllImport("user32.dll")]
internal static extern uint GetWindowThreadProcessId(IntPtr hWnd, IntPtr voidProcessId);
[DllImport("user32.dll", SetLastError = false)]
internal static extern IntPtr SetWinEventHook(
SWEH_Events eventMin,
SWEH_Events eventMax,
IntPtr hmodWinEventProc,
Hook.WinEventDelegate lpfnWinEventProc,
uint idProcess, uint idThread,
SWEH_dwFlags dwFlags);
[DllImport("user32.dll", SetLastError = false)]
internal static extern bool UnhookWinEvent(IntPtr hWinEventHook);
}
Thanks to #Jimi for his help here. The following method worked.
First, store a reference to the target process:
Process _target = Process.GetProcessesByName("target")[0];
Then get the handle to the main window:
IntPtr _tagetHWnd = _target.MainWindowHandle;
Then initialise the hook:
SetWinEventHook(EVENT_OBJECT_LOCATIONCHANGE, EVENT_OBJECT_LOCATIONCHANGE, IntPtr.Zero, TargetMoved, (uint)_foxview.Id,
GetWindowThreadProcessId(_foxview.MainWindowHandle, IntPtr.Zero), WINEVENT_OUTOFCONTEXT | WINEVENT_SKIPOWNPROCESS | WINEVENT_SKIPOWNTHREAD);
Where SetWinEventHook is declared as such:
[DllImport("user32.dll")]
private static extern IntPtr SetWinEventHook(uint eventMin, uint eventMax, IntPtr hmodWinEventProc, WinEventDelegate lpfnWinEventProc, uint idProcess, uint idThread, uint dwFlags);
And the constants involved are:
private const uint EVENT_OBJECT_LOCATIONCHANGE = 0x800B;
private const int HT_CAPTION = 0x2;
private const uint WINEVENT_OUTOFCONTEXT = 0x0000;
private const uint WINEVENT_SKIPOWNPROCESS = 0x0002;
private const uint WINEVENT_SKIPOWNTHREAD = 0x0001;
private const int WM_NCLBUTTONDOWN = 0xA1;
Then in my TargetMoved method I get check the new Window location and move my overlay.
private void TargetMoved(IntPtr hWinEventHook, uint eventType, IntPtr lParam, int idObject, int idChild, uint dwEventThread, uint dwmsEventTime)
{
Rect newLocation = new Rect();
GetWindowRect(_foxViewHWnd, ref newLocation);
Location = new Point(newLocation.Right - (250 + _currentUser.Length * 7), newLocation.Top + 5);
}
Where GetWindowRect() is defined by:
[DllImport("user32.dll", SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
private static extern bool GetWindowRect(IntPtr hWnd, ref Rect lpRect);
And Rect is defined by:
[StructLayout(LayoutKind.Sequential)]
private struct Rect
{
public readonly int Left;
public readonly int Top;
public readonly int Right;
public readonly int Bottom;
}
So when you put it all together, the entire class now looks like this:
using System;
using System.Diagnostics;
using System.Drawing;
using System.Runtime.InteropServices;
using System.Windows.Forms;
using UserMonitor;
namespace OnScreenOverlay
{
public partial class Overlay : Form
{
#region Public Fields
public const string UserCache = #"redacted";
#endregion Public Fields
#region Private Fields
private const uint EVENT_OBJECT_LOCATIONCHANGE = 0x800B;
private const uint WINEVENT_OUTOFCONTEXT = 0x0000;
private const uint WINEVENT_SKIPOWNPROCESS = 0x0002;
private const uint WINEVENT_SKIPOWNTHREAD = 0x0001;
private readonly Process _foxview;
private readonly IntPtr _foxViewHWnd;
private readonly UserMon _monitor;
private string _currentUser;
#endregion Private Fields
#region Public Constructors
public Overlay()
{
InitializeComponent();
_target= Process.GetProcessesByName("target")[0];
if (_foxview == null)
{
MessageBox.Show("No target detected... Closing");
Close();
}
_targetHWnd = _target.MainWindowHandle;
InitializeWinHook();
StartPosition = FormStartPosition.Manual;
Location = new Point(Screen.PrimaryScreen.Bounds.Left + 20, Screen.PrimaryScreen.Bounds.Bottom - 20);
ShowInTaskbar = false;
_monitor = new UserMon(UserCache);
_monitor.UserChanged += (s, a) =>
{
_currentUser = a.Value;
if (pictBox.InvokeRequired)
{
pictBox.Invoke((MethodInvoker)delegate { pictBox.Refresh(); });
}
};
_currentUser = _monitor.GetUser();
}
#endregion Public Constructors
#region Private Delegates
private delegate void WinEventDelegate(IntPtr hWinEventHook, uint eventType,
IntPtr hwnd, int idObject, int idChild, uint dwEventThread, uint dwmsEventTime);
#endregion Private Delegates
#region Private Methods
[DllImport("user32.dll", SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
private static extern bool GetWindowRect(IntPtr hWnd, ref Rect lpRect);
[DllImport("user32.dll", SetLastError = true)]
private static extern uint GetWindowThreadProcessId(IntPtr hWnd, IntPtr processId);
[DllImport("user32.dll")]
private static extern IntPtr SetWinEventHook(uint eventMin, uint eventMax, IntPtr
hmodWinEventProc, WinEventDelegate lpfnWinEventProc, uint idProcess,
uint idThread, uint dwFlags);
private void InitializeWinHook()
{
SetWinEventHook(EVENT_OBJECT_LOCATIONCHANGE, EVENT_OBJECT_LOCATIONCHANGE, IntPtr.Zero, TargetMoved, (uint)_foxview.Id,
GetWindowThreadProcessId(_foxview.MainWindowHandle, IntPtr.Zero), WINEVENT_OUTOFCONTEXT | WINEVENT_SKIPOWNPROCESS | WINEVENT_SKIPOWNTHREAD);
}
private void Overlay_FormClosing(object sender, FormClosingEventArgs e)
{
_monitor.Dispose();
}
private void pictBox_Paint(object sender, PaintEventArgs e)
{
using (Font myFont = new Font("Arial", 8))
{
e.Graphics.DrawString($"User: {_currentUser}", myFont, Brushes.LimeGreen, new Point(2, 2));
}
}
private void TargetMoved(IntPtr hWinEventHook, uint eventType, IntPtr lParam, int idObject, int idChild, uint dwEventThread, uint dwmsEventTime)
{
Rect newLocation = new Rect();
GetWindowRect(_foxViewHWnd, ref newLocation);
Location = new Point(newLocation.Right - (250 + _currentUser.Length * 7), newLocation.Top + 5);
}
#endregion Private Methods
#region Private Structs
[StructLayout(LayoutKind.Sequential)]
private struct Rect
{
public readonly int Left;
public readonly int Top;
public readonly int Right;
public readonly int Bottom;
}
#endregion Private Structs
}
}
I have a WPF window that is supposed to be a "desktop gadget".
My users are asking for a way to prevent it from disappearing when they hit "Show Desktop".
Making the window always topmost works but some of my users do not want the window always on top.
Short of running a timer every x seconds to activate the window, is there a proper way to achieve this?
I ended up developing my own solution.
I scoured the internet for weeks trying to find an answer so I'm kind of proud of this one.
So what we do is use pinvoke to create a hook for the EVENT_SYSTEM_FOREGROUND window event.
This event triggers whenever the foreground window is changed.
Now what I noticed is when the "Show Desktop" command is issued, the WorkerW window class becomes foreground.
Note this WorkerW window is not the desktop and I confirmed the hwnd of this WorkerW window is not the Desktop hwnd.
So what we do is whenever the WorkerW window becomes the foreground, we set our "WPF Gadget Window" to be topmost!
Whenever a window other the WorkerW window becomes the foreground, we remove topmost from our "WPF Gadget Window".
If you want to take it a step further, you can uncomment out the part where I check if the new foreground window is also "PROGMAN", which is the Desktop window.
However, this will lead to your window becoming topmost if the user clicks their desktop on a different monitor. In my case, I did not want this behavior, but I figured some of you might.
Confirmed to work in Windows 10. Should work in older versions of Windows.
using System;
using System.Runtime.InteropServices;
using System.Text;
using System.Windows;
namespace YourNamespace
{
internal static class NativeMethods
{
[DllImport("user32.dll")]
internal static extern IntPtr SetWinEventHook(uint eventMin, uint eventMax, IntPtr hmodWinEventProc, ShowDesktop.WinEventDelegate lpfnWinEventProc, uint idProcess, uint idThread, uint dwFlags);
[DllImport("user32.dll")]
internal static extern bool UnhookWinEvent(IntPtr hWinEventHook);
[DllImport("user32.dll")]
internal static extern int GetClassName(IntPtr hwnd, StringBuilder name, int count);
}
public static class ShowDesktop
{
private const uint WINEVENT_OUTOFCONTEXT = 0u;
private const uint EVENT_SYSTEM_FOREGROUND = 3u;
private const string WORKERW = "WorkerW";
private const string PROGMAN = "Progman";
public static void AddHook(Window window)
{
if (IsHooked)
{
return;
}
IsHooked = true;
_delegate = new WinEventDelegate(WinEventHook);
_hookIntPtr = NativeMethods.SetWinEventHook(EVENT_SYSTEM_FOREGROUND, EVENT_SYSTEM_FOREGROUND, IntPtr.Zero, _delegate, 0, 0, WINEVENT_OUTOFCONTEXT);
_window = window;
}
public static void RemoveHook()
{
if (!IsHooked)
{
return;
}
IsHooked = false;
NativeMethods.UnhookWinEvent(_hookIntPtr.Value);
_delegate = null;
_hookIntPtr = null;
_window = null;
}
private static string GetWindowClass(IntPtr hwnd)
{
StringBuilder _sb = new StringBuilder(32);
NativeMethods.GetClassName(hwnd, _sb, _sb.Capacity);
return _sb.ToString();
}
internal delegate void WinEventDelegate(IntPtr hWinEventHook, uint eventType, IntPtr hwnd, int idObject, int idChild, uint dwEventThread, uint dwmsEventTime);
private static void WinEventHook(IntPtr hWinEventHook, uint eventType, IntPtr hwnd, int idObject, int idChild, uint dwEventThread, uint dwmsEventTime)
{
if (eventType == EVENT_SYSTEM_FOREGROUND)
{
string _class = GetWindowClass(hwnd);
if (string.Equals(_class, WORKERW, StringComparison.Ordinal) /*|| string.Equals(_class, PROGMAN, StringComparison.Ordinal)*/ )
{
_window.Topmost = true;
}
else
{
_window.Topmost = false;
}
}
}
public static bool IsHooked { get; private set; } = false;
private static IntPtr? _hookIntPtr { get; set; }
private static WinEventDelegate _delegate { get; set; }
private static Window _window { get; set; }
}
}
You can use "StateChanged" event of the window. It fires when "WindowState" property changes. You can use this event and maximize the window when the state changed to minimized.
UPDATE
Try this code:
private async void Window_StateChanged_1(object sender, EventArgs e)
{
await MaximizeWindow(this);
}
public Task MaximizeWindow(Window window)
{
return Task.Factory.StartNew(() =>
{
this.Dispatcher.Invoke((Action)(() =>
{
Thread.Sleep(100);
window.WindowState = System.Windows.WindowState.Maximized;
}));
});
}