Determine if a window is topmost or not - c#

I am able to set a windows position as topmost and also setting it no topmost with SetWindowPos. But i can't figure out how to check if a window is topmost or not. Is there any Method to check if a window is topmost or not with pinvoke?

You can use the GetWindowLong() function to check the Extended Window Styles.
Untested, but I believe it should work:
[DllImport("user32.dll", SetLastError=true)]
static extern int GetWindowLong(IntPtr hWnd, int nIndex);
const int GWL_EXSTYLE = -20;
const int WS_EX_TOPMOST = 0x0008;
public static bool IsWindowTopMost(IntPtr hWnd)
{
int exStyle = GetWindowLong(hWnd, GWL_EXSTYLE);
return (exStyle & WS_EX_TOPMOST) == WS_EX_TOPMOST;
}

Depending on the UI technology you*re using, you can choose of the following two:
Windows Forms: Form.TopMost
WPF: Window.TopMost
You can you those properties to check if a certain window is topmost and you can also use these to set a window topmost. I'd prefer these in favor of any win32 methods.

Related

new window postion inside the panel in windows form app [duplicate]

I'm trying to set childForm as the child of the main Excel window using the SetParent API through PInvoke:
Form childForm = new MyForm();
IntPtr excelHandle = (IntPtr) excelApplication.Hwnd;
SetParent(childForm.Handle, excelHandle);
childForm.StartPosition = FormStartPosition.Manual;
childForm.Left = 0;
childForm.Top = 0;
As you can see above, my intention is also to position the child in the top left corner of Excel window. However, for some reason the childForm always ends up at some weird location.
What is it that I am doing wrong?
While all answers here suggest perfectly logical approaches, none of them worked for me. Then I tried MoveWindow. For some reason I don't understand, it did the job.
Here's the code:
[DllImport("user32.dll", SetLastError = true)]
internal static extern bool MoveWindow(IntPtr hWnd, int X, int Y, int nWidth, int nHeight, bool bRepaint);
...
Form childForm = new MyForm();
IntPtr excelHandle = (IntPtr) excelApplication.Hwnd;
SetParent(childForm.Handle, excelHandle);
MoveWindow(childForm.Handle, 0, 0, childForm.Width, childForm.Height, true);
When using SetParent on a form that is currently a child of the desktop (in other words, one without a parent
set), you must set the WS_CHILD style and remove the WS_POPUP style. (See the Remarks section of the MSDN entry.) Windows requires that all owned windows have the WS_CHILD style set. This could also be causing the left and top properties to report/set the wrong values because the form doesn't know who it's daddy is. You can fix this by calling SetWindowLong after SetParent, but before you try to set the location:
//Remove WS_POPUP style and add WS_CHILD style
const UInt32 WS_POPUP = 0x80000000;
const UInt32 WS_CHILD = 0x40000000;
int style = GetWindowLong(this.Handle, GWL_STYLE);
style = (style & ~(WS_POPUP)) | WS_CHILD;
SetWindowLong(this.Handle, GWL_STYLE, style);
It depends on your ShowDialog call I believe. If you call ShowDialog without the parent paremeter, the parent is reset.
You could create a wrapper class that implements IWin32Window and returns the HWND to excel. Then you could pass that to the ShowDialog call of childForm.
You could also query the position of the excel application using GetWindowPos and then set the childForm accordingly.
Try a few things to diagnose the problem:
Put a breakpoint after setting Left
and Top, do Left and Top read zero?
Call SetParent last.
Make a method that sets Left and Top
again, and BeginInvoke the method.
Make sure your child window is really
the child. To do this call
ShowDialog, and try to click the
parent window. Make sure windows
prevents focus to the parent window.
Assuming you know how to get the hwnds of the windows you want to set z-order of, you can use this pInvoke:
public stati class WindowsApi
{
[DllImport("user32.dll")]
public static extern bool SetWindowPos(IntPtr hWnd, IntPtr hWndInsertAfter,
int X, int Y, int cx, int cy, uint uFlags);
}
public class WindowZOrderPositioner
{
public void SetZOrder(IntPtr targetHwnd, IntPtr insertAfter)
{
IntPtr nextHwnd = IntPtr.Zero;
WindowsAPI.SetWindowPos(targetHwnd, insertAfter, 0, 0, 0, 0, SetWindowPosFlags.NoMove | SetWindowPosFlags.NoSize | SetWindowPosFlags.NoActivate);
}

How to keep border on a fixed form?

I want my Windows Forms form to keep the window border, while having no title bar and being non-resizable (fixed) (similarly to window previews, when one hovers mouse over button on the taskbar):
Setting ControlBox to false and Text to "" removes the title bar and keeps the border as I want to, but the border is visible only if the form is sizeable. When I set the FormBorderStyle to one of the Fixed* styles, the border disappears:
How may I achieve the described behavior?
You can pinvoke SetWindowsLong and adjust window styles:
// run in LINQpad
private const int GWL_STYLE = -16;
private const int WS_SIZEBOX = 0x040000;
[DllImport("user32.dll", SetLastError = true)]
private static extern int GetWindowLong(IntPtr hWnd, int nIndex);
[DllImport("user32.dll")]
private static extern int SetWindowLong(IntPtr hWnd, int nIndex, int dwNewLong);
void Main()
{
var form = new Form();
form.ControlBox = false;
form.FormBorderStyle = FormBorderStyle.FixedDialog;
form.Show();
SetWindowLong(form.Handle, GWL_STYLE, GetWindowLong(form.Handle, GWL_STYLE) | WS_SIZEBOX);
}
After that you would have to prevent resizing manually though.
I just played around with a project of mine and set FormBorderStyle to FixedSingle through the Design view, and the window seems to keep the border for Windows 8. I initially had text in the title, which was forcing the border to render. I removed the text and the border no longer rendered, so as a hacky solution I just input an empty string, by hitting backspace a few times. This made the border show up and remain fixed.

Hosting external app in WPF window

We are developing a layout manager in WPF that has viewports which can be moved/resized/etc by a user. Viewports are normally filled with data (pictures/movies/etc) via providers that are under our control in the layout manager. My job is to examine if its also possible to host any external Windows app (i.e. notepad, calc, adobe reader, etc) in a viewport. I encounter a number of problems.
Most resources point to using the HwndHost class. I am experimenting with this walkthrough from Microsoft itself: http://msdn.microsoft.com/en-us/library/ms752055.aspx
I've adapted this so the list box is replaced with the windows handle from the external application. Can anybody help me out with these questions:
The walkthrough adds an extra static sub window in which the ListBox is placed. I don't think I need that for external apps. If I ommit it, I have to make the external app a child window (using Get/SetWindowLong from user32.dll to set GWL_STYLE as WS_CHILD). But if I do that, the menu bar of the app dissapears (because of the WS_CHILD style) and it no longer receives input.
If I do use the sub window, and make the external app a child of that things work reasonably, but sometimes the external app does not paint ok.
Also, I need the child window to resize to the viewport. Is this possible?
When the exernal app spawns a child window (i.e. Notepad->Help->About), this window is not hosted by the HwndHost (and thus can be moved outside the viewport). Is there any way I can prevent that?
Since I need no further interaction between the external application and the layout manager, am I right in assuming I do not need to catch and forward messages? (the walkthrough adds a HwndSourceHook to the sub window to catch selection changes in the listbox).
When you run the (unmodified) example VS2010 and close the window, VS2010 does not see that the program ended. If you break-all, you end up in assembly without source. Something smelly is going on, but I cannot find it.
The walkthrough itself seems to be very sloppy coded, but I have not found any better documentation on this subject. Any other examples?
Another approach is not to use HwndHost but WindowsFormHost as discussed here. It works (and is much simpler!) but I do not have control over the size of the application? Also, WinFormHost is not really meant for this?
Thanks for any pointers in the right direction.
Well... if the question had been posed like 20 years ago, one would have answer, "Sure, look at 'OLE'!", here is a link to what is "Object Linking and Embedding":
http://en.wikipedia.org/wiki/Object_Linking_and_Embedding
If you read this article, you will see the number of interfaces this spec defined, not because its author thought it was fun, but because it's technically difficult to achieve in the general cases
It's actually still supported by some apps (mostly Microsoft ones, as Microsoft was almost the only sponsor of OLE...)
You can embed these apps using something called DSOFramer (see links here on SO: MS KB311765 and DsoFramer are missing from MS site), a component that allows you to host OLE server (ie: external apps running as another process)
visually inside an application. It's some kind of a big hack Microsoft let out a few years ago, that is not supported anymore to the point that the binaries are quite difficult to find!
It (may) still works for simple OLE servers, but I think I read somewhere it does not even work for new Microsoft applications such as Word 2010.
So, you can use DSOFramer for application that support it. You can try it.
For others applications, well, today, in the modern world we live in, you don't host applications, ran in external process, you host components, and they are in general supposed to run inprocess.
That's why you will have great difficulties to do what you want to do in general. One problem you will face (and not the least with recent versions of Windows) is security: how can your process I don't trust can legitimately handle my windows and menus created by my process :-) ?
Still, you can do quite a lot application by application, using various Windows hack.
SetParent is basically the mother of all hacks :-)
Here is a piece of code that extends the sample you point, adding automatic resize, and the removal of the caption box.
It demonstrates how to implicitely remove the control box, the system menu, as an example:
public partial class Window1 : Window
{
private System.Windows.Forms.Panel _panel;
private Process _process;
public Window1()
{
InitializeComponent();
_panel = new System.Windows.Forms.Panel();
windowsFormsHost1.Child = _panel;
}
[DllImport("user32.dll")]
private static extern int SetWindowLong(IntPtr hWnd, int nIndex, int dwNewLong);
[DllImport("user32.dll", SetLastError = true)]
private static extern int GetWindowLong(IntPtr hWnd, int nIndex);
[DllImport("user32")]
private static extern IntPtr SetParent(IntPtr hWnd, IntPtr hWndParent);
[DllImport("user32")]
private static extern bool SetWindowPos(IntPtr hWnd, IntPtr hWndInsertAfter, int X, int Y, int cx, int cy, int uFlags);
private const int SWP_NOZORDER = 0x0004;
private const int SWP_NOACTIVATE = 0x0010;
private const int GWL_STYLE = -16;
private const int WS_CAPTION = 0x00C00000;
private const int WS_THICKFRAME = 0x00040000;
private void button1_Click(object sender, RoutedEventArgs e)
{
button1.Visibility = Visibility.Hidden;
ProcessStartInfo psi = new ProcessStartInfo("notepad.exe");
_process = Process.Start(psi);
_process.WaitForInputIdle();
SetParent(_process.MainWindowHandle, _panel.Handle);
// remove control box
int style = GetWindowLong(_process.MainWindowHandle, GWL_STYLE);
style = style & ~WS_CAPTION & ~WS_THICKFRAME;
SetWindowLong(_process.MainWindowHandle, GWL_STYLE, style);
// resize embedded application & refresh
ResizeEmbeddedApp();
}
protected override void OnClosing(System.ComponentModel.CancelEventArgs e)
{
base.OnClosing(e);
if (_process != null)
{
_process.Refresh();
_process.Close();
}
}
private void ResizeEmbeddedApp()
{
if (_process == null)
return;
SetWindowPos(_process.MainWindowHandle, IntPtr.Zero, 0, 0, (int)_panel.ClientSize.Width, (int)_panel.ClientSize.Height, SWP_NOZORDER | SWP_NOACTIVATE);
}
protected override Size MeasureOverride(Size availableSize)
{
Size size = base.MeasureOverride(availableSize);
ResizeEmbeddedApp();
return size;
}
}
This is basically all Windows "traditional" hacks. You could also remove item menus you don't like, as explained here: http://support.microsoft.com/kb/110393/en-us (How to Remove Menu Items from a Form's Control-Menu Box).
You can also replace "notepad.exe" by "winword.exe" and it seems to work. But there are limitations to this (keyboard, mouse, focus, etc.).
Good luck!
Simon Mourier's answer is extremely well written. However, when I tried it with a winform app made by myself, it failed.
_process.WaitForInputIdle();
can be replaced by
while (_process.MainWindowHandle==IntPtr.Zero)
{
Thread.Sleep(1);
}
and everything goes smoothly.
Thank you for the great question and all of you for your answers.
After reading the answers in this thread and doing some trial and error myself I ended up with something that works pretty well, but of course some things will need your attention for special cases.
I used the HwndHostEx as base class for my host class, you can find it here: http://microsoftdwayneneed.codeplex.com/SourceControl/changeset/view/69631#1034035
Example code:
public class NotepadHwndHost : HwndHostEx
{
private Process _process;
protected override HWND BuildWindowOverride(HWND hwndParent)
{
ProcessStartInfo psi = new ProcessStartInfo("notepad.exe");
_process = Process.Start(psi);
_process.WaitForInputIdle();
// The main window handle may be unavailable for a while, just wait for it
while (_process.MainWindowHandle == IntPtr.Zero)
{
Thread.Yield();
}
HWND hwnd = new HWND(_process.MainWindowHandle);
const int GWL_STYLE = -16;
const int BORDER = 0x00800000;
const int DLGFRAME = 0x00400000;
const int WS_CAPTION = BORDER | DLGFRAME;
const int WS_THICKFRAME = 0x00040000;
const int WS_CHILD = 0x40000000;
int style = GetWindowLong(notepadHandle, GWL_STYLE);
style = style & ~WS_CAPTION & ~WS_THICKFRAME; // Removes Caption bar and the sizing border
style |= WS_CHILD; // Must be a child window to be hosted
NativeMethods.SetWindowLong(hwnd, GWL.STYLE, style);
return hwnd;
}
protected override void DestroyWindowOverride(HWND hwnd)
{
_process.CloseMainWindow();
_process.WaitForExit(5000);
if (_process.HasExited == false)
{
_process.Kill();
}
_process.Close();
_process.Dispose();
_process = null;
hwnd.Dispose();
hwnd = null;
}
}
The HWND, NativeMethods and enums comes from the DwayneNeed library as well (Microsoft.DwayneNeed.User32).
Just add the NotepadHwndHost as a child in a WPF window and you should see the notepad window hosted there.
The solution is incredibly involved. Lots of code. Here's a few hints.
First, you are on the right track.
You do have to use the HwndHost and HwndSource thing. If you don't, you'll get visual artifacts. Like flicker. A warning, if you don't use the Host and Source, it will seem like it will work, but it won't in the end -- it will have random little stupid bugs.
Take a look at this for some hints. It's not complete, but it will help you go in the right direction.
http://microsoftdwayneneed.codeplex.com/SourceControl/changeset/view/50925#1029346
You have to get into Win32 to control a lot of what you are asking about. You do need to catch and forward messages. You do need to control which windows "own" the child windows.
Use Spy++ alot.
I have this running in production and so far so good in a WPF application. Make sure you call SetNativeWindowInWPFWindowAsChild() from UI thread that owns window.
public static bool SetNativeWindowInWPFWindowAsChild(IntPtr hWndNative, Window window)
{
UInt32 dwSyleToRemove = WS_POPUP | WS_CAPTION | WS_THICKFRAME;
UInt32 dwExStyleToRemove = WS_EX_DLGMODALFRAME | WS_EX_WINDOWEDGE | WS_EX_CLIENTEDGE | WS_EX_STATICEDGE;
UInt32 dwStyle = GetWindowLong(hWndNative, GWL_STYLE);
UInt32 dwExStyle = GetWindowLong(hWndNative, GWL_EXSTYLE);
dwStyle &= ~dwSyleToRemove;
dwExStyle &= ~dwExStyleToRemove;
SetWindowLong(hWndNative, GWL_STYLE, dwStyle | WS_CHILD);
SetWindowLong(hWndNative, GWL_EXSTYLE, dwExStyle);
IntPtr hWndOld = SetParent(hWndNative, new WindowInteropHelper(window).Handle);
if (hWndOld == IntPtr.Zero)
{
System.Diagnostics.Debug.WriteLine("SetParent() Failed -> LAST ERROR: " + Marshal.GetLastWin32Error() + "\n");
}
return hWndOld != IntPtr.Zero;
}
Here is the Native Win32 API I used. (There are extras in here because I size/focus the window after it's set)
[StructLayout(LayoutKind.Sequential)]
private struct RECT
{
public Int32 left;
public Int32 top;
public Int32 right;
public Int32 bottom;
}
[DllImport("user32.dll", SetLastError = true)]
private static extern IntPtr SetParent(IntPtr hWndChild, IntPtr hWndNewParent);
[DllImport("user32.dll")]
private static extern UInt32 SetWindowLong(IntPtr hWnd, int nIndex, UInt32 dwNewLong);
[DllImport("user32.dll")]
private static extern UInt32 GetWindowLong(IntPtr hWnd, int nIndex);
[DllImport("user32.dll")]
private static extern bool GetWindowRect(IntPtr hWnd, out RECT lpRect);
[DllImport("user32.dll")]
private static extern IntPtr SetFocus(IntPtr hWnd);
[DllImport("user32.dll")]
private static extern bool SetWindowPos(IntPtr hWnd, IntPtr hWndInsertAfter, int X, int Y, int cx, int cy, SetWindowPosFlags uFlags);
private static int GWL_STYLE = -16;
private static int GWL_EXSTYLE = -20;
private static UInt32 WS_CHILD = 0x40000000;
private static UInt32 WS_POPUP = 0x80000000;
private static UInt32 WS_CAPTION = 0x00C00000;
private static UInt32 WS_THICKFRAME = 0x00040000;
private static UInt32 WS_EX_DLGMODALFRAME = 0x00000001;
private static UInt32 WS_EX_WINDOWEDGE = 0x00000100;
private static UInt32 WS_EX_CLIENTEDGE = 0x00000200;
private static UInt32 WS_EX_STATICEDGE = 0x00020000;
[Flags]
private enum SetWindowPosFlags : uint
{
SWP_ASYNCWINDOWPOS = 0x4000,
SWP_DEFERERASE = 0x2000,
SWP_DRAWFRAME = 0x0020,
SWP_FRAMECHANGED = 0x0020,
SWP_HIDEWINDOW = 0x0080,
SWP_NOACTIVATE = 0x0010,
SWP_NOCOPYBITS = 0x0100,
SWP_NOMOVE = 0x0002,
SWP_NOOWNERZORDER = 0x0200,
SWP_NOREDRAW = 0x0008,
SWP_NOREPOSITION = 0x0200,
SWP_NOSENDCHANGING = 0x0400,
SWP_NOSIZE = 0x0001,
SWP_NOZORDER = 0x0004,
SWP_SHOWWINDOW = 0x0040
}
private static readonly IntPtr HWND_TOPMOST = new IntPtr(-1);
private static readonly IntPtr HWND_NOTOPMOST = new IntPtr(-2);
private static readonly IntPtr HWND_TOP = new IntPtr(0);
private static readonly IntPtr HWND_BOTTOM = new IntPtr(1);
Check out my answer to: How to run an application inside wpf application?
I managed to get the notepad example working without DwayneNeed jiggery. I just added SetParent() and boom... she works just like the DwayneNeed example.

How do I prevent the original form from losing focus when I show another form?

I am having a problem where my main form loses focus when opening a new form. I know I can revert the focus back by using mainForm.focus(), but how do I handle things if I want the main form to never give up its focus when new window is opened?
You can accomplish this by overriding the property ShowWithoutActivation in order for it to return true in the forms that you want to show without stealing focus from the form that shown it, in your case that would be your main form.
Cody Gray answered this, I'm just expanding it by directly pasting the code. Someone with edit rights can copy it over there and delete this for all I care ;)
pinvoke.net's ShowWindow method.:
private const int SW_SHOWNOACTIVATE = 4;
private const int HWND_TOPMOST = -1;
private const uint SWP_NOACTIVATE = 0x0010;
[DllImport("user32.dll", EntryPoint = "SetWindowPos")]
static extern bool SetWindowPos(
int hWnd, // window handle
int hWndInsertAfter, // placement-order handle
int X, // horizontal position
int Y, // vertical position
int cx, // width
int cy, // height
uint uFlags); // window positioning flags
[DllImport("user32.dll")]
static extern bool ShowWindow(IntPtr hWnd, int nCmdShow);
static void ShowInactiveTopmost(Form frm)
{
ShowWindow(frm.Handle, SW_SHOWNOACTIVATE);
SetWindowPos(frm.Handle.ToInt32(), HWND_TOPMOST,frm.Left, frm.Top, frm.Width, frm.Height,SWP_NOACTIVATE);
frm.TopMost = false;
}

Problem positioning window when using SetParent()

I'm trying to set childForm as the child of the main Excel window using the SetParent API through PInvoke:
Form childForm = new MyForm();
IntPtr excelHandle = (IntPtr) excelApplication.Hwnd;
SetParent(childForm.Handle, excelHandle);
childForm.StartPosition = FormStartPosition.Manual;
childForm.Left = 0;
childForm.Top = 0;
As you can see above, my intention is also to position the child in the top left corner of Excel window. However, for some reason the childForm always ends up at some weird location.
What is it that I am doing wrong?
While all answers here suggest perfectly logical approaches, none of them worked for me. Then I tried MoveWindow. For some reason I don't understand, it did the job.
Here's the code:
[DllImport("user32.dll", SetLastError = true)]
internal static extern bool MoveWindow(IntPtr hWnd, int X, int Y, int nWidth, int nHeight, bool bRepaint);
...
Form childForm = new MyForm();
IntPtr excelHandle = (IntPtr) excelApplication.Hwnd;
SetParent(childForm.Handle, excelHandle);
MoveWindow(childForm.Handle, 0, 0, childForm.Width, childForm.Height, true);
When using SetParent on a form that is currently a child of the desktop (in other words, one without a parent
set), you must set the WS_CHILD style and remove the WS_POPUP style. (See the Remarks section of the MSDN entry.) Windows requires that all owned windows have the WS_CHILD style set. This could also be causing the left and top properties to report/set the wrong values because the form doesn't know who it's daddy is. You can fix this by calling SetWindowLong after SetParent, but before you try to set the location:
//Remove WS_POPUP style and add WS_CHILD style
const UInt32 WS_POPUP = 0x80000000;
const UInt32 WS_CHILD = 0x40000000;
int style = GetWindowLong(this.Handle, GWL_STYLE);
style = (style & ~(WS_POPUP)) | WS_CHILD;
SetWindowLong(this.Handle, GWL_STYLE, style);
It depends on your ShowDialog call I believe. If you call ShowDialog without the parent paremeter, the parent is reset.
You could create a wrapper class that implements IWin32Window and returns the HWND to excel. Then you could pass that to the ShowDialog call of childForm.
You could also query the position of the excel application using GetWindowPos and then set the childForm accordingly.
Try a few things to diagnose the problem:
Put a breakpoint after setting Left
and Top, do Left and Top read zero?
Call SetParent last.
Make a method that sets Left and Top
again, and BeginInvoke the method.
Make sure your child window is really
the child. To do this call
ShowDialog, and try to click the
parent window. Make sure windows
prevents focus to the parent window.
Assuming you know how to get the hwnds of the windows you want to set z-order of, you can use this pInvoke:
public stati class WindowsApi
{
[DllImport("user32.dll")]
public static extern bool SetWindowPos(IntPtr hWnd, IntPtr hWndInsertAfter,
int X, int Y, int cx, int cy, uint uFlags);
}
public class WindowZOrderPositioner
{
public void SetZOrder(IntPtr targetHwnd, IntPtr insertAfter)
{
IntPtr nextHwnd = IntPtr.Zero;
WindowsAPI.SetWindowPos(targetHwnd, insertAfter, 0, 0, 0, 0, SetWindowPosFlags.NoMove | SetWindowPosFlags.NoSize | SetWindowPosFlags.NoActivate);
}

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