I have created a WPF application that has no chrome and a transparent background
WindowStyle="None" AllowsTransparency="True"
IntPtr windowHandle = new WindowInteropHelper(window).Handle;
IntPtr oldParent = SetParent(windowHandle, desktopHandle);
But whenever i try to set this window to be a child of the desktop process (So that it isn't affected by "Show Desktop" commands) it stops drawing. If i change AllowsTransparency back to False it works as expected, however I do want it to be transparent and have no borders.
Can anyone give me any suggestions on how to make this work correctly? I can get this to work by using the same method in a Winforms application.
I suspect that the reason it worked for Winforms and not for WPF is that Winforms uses GDI for rendering and WPF uses DirectX. These technologies have interoperability issues that are more fully detailed here, in particular in a section called "Transparency and Top-Level Windows".
http://msdn.microsoft.com/en-us/library/aa970688.aspx
You might be able work around the issue by hosting the WPF visual in a Win32 window, as detailed here:
http://msdn.microsoft.com/en-us/library/ms742522.aspx#hosting_a_wpf_page
Related
I currently have LibVLC setup with a C# project and it uses a Panel to output the video stream. As WPF is better suited for some GUI options I want to implement, I have now switched my project over to it. However, I noticed that WPF Controls don't have handles like C# controls do.
I have found these...
http://wpfmediakit.codeplex.com/
http://videorendererelement.codeplex.com
However I am new to WPF and have no idea how to actually integrate them. What would be the best approach to output the video streams from LibVlC in WPF?
I managed to resolve this by using a WindowsFormsHost control and just use a Panel as I was doing previously in my Win Forms application. Still seems that using something else native to WPF would be preferable, but for now this is working fine.
I'm afraid that's not possible...
Since WPF controls are not Win32 controls behind the scenes (the MS specific HWND or the more general HANDLE), like most WinForms controls are, providing a HANDLE to libvlc for rendering is not possible or not easy.
See here
All WPF elements on the screen are ultimately backed by a HWND. When you create a WPF Window, WPF creates a top-level HWND, and uses an HwndSource to put the Window and its WPF content inside the HWND. The rest of your WPF content in the application shares that singular HWND. An exception is menus, combo box drop downs, and other pop-ups. These elements create their own top-level window, which is why a WPF menu can potentially go past the edge of the window HWND that contains it.
You could try to use a Window and attempt to get its Handle like this:
IntPtr windowHandle = new WindowInteropHelper(windowInstance).Handle
Then pass this handle to libvlc. Remember to obtain this handle no sooner than inside the Loaded event of the window, see here
But this will limit you to using a top level Window control, which doesn't seem to be what you want.
I've done some searching, but I can't find an exact answer on this. In my C# WPF app, I get the HWND pointer and pass it to a C dll. That C dll then attempts to use GDI calls to render an overlay of sorts on my window. There are no errors, but nothing appears. If I switch to a Windows Form, the dll can render over it fine. If I host a WindowsFormHost control and use the hwnd from there I have the same effect. I've seen information on the HwndHost control but it doesn't really look like what I want. Perhaps someone with more knowledge of that control can tell me differently. I read somewhere that an hwnd used for DirectX rendering (like WPF) can't also use GDI. Does this make my scenario impossible? I could fake it by overlaying a borderless form over the WPF window, but obviously that wouldn't be too pretty. Any thoughts or ideas?
You can't have WPF and GDI rendering to the same hwnd but you can easily have a child hwnd inside of your WPF app and let GDI render into it. Take a look at HwndHost for doing that. The section "Hosting a Microsoft Win32 Window in WPF" in this article has a little more details. It also talks about the various issues you'll run into (like airspace) when doing this type of interop.
Is it possible to have a project containing both Winforms and WPF?
Say a WinForm project that is transformed step by step(form by form) in a WPF one, will be possible to have a Winform opening on a button, and a WPF one opening on a other button?
Yes. You have to pick one technology to display each physical window and control in your app, but there's no reason why you can't mix and match.
For example:
A WinForms window can show a WPF window.
A WPF window can show a WinForms window.
A WinForms window can contain WPF content (see the ElementHost control).
A WPF window can contain WinForms controls (see the WindowsFormsHost control).
This works great.
One can have WPF windows in Windows Forms and Windows Forms windows in WPF
http://msdn.microsoft.com/en-us/library/ms745781.aspx
http://msdn.microsoft.com/en-us/library/system.windows.forms.integration.windowsformshost.aspx
Adding Winforms to WPF projects can be done smoothly (directly from the "Add new item" menu), but there is not straight option to add a WPF window to a Winforms project. Still, I handled to do it following these steps:
Add a WPF User Control (this option is available on the "Add new
item" menu) and then convert it into a WPF Window. Modify the XAML
changing the UserControl parent tag to Window, and remove the
inheritance from UserControl (all of this is explained in this link).
Add a reference to System.Xaml.dll. See this link.
Add a reference to System.Windows.dll (I found it on my computer on this path: C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETFramework\v4.5. Be aware it might be different in yours). See this link.
What you might be looking for is the ElementHost control. What it lets you do is take WPF content and host it in a Windows Forms window. More details are here:
http://msdn.microsoft.com/en-us/library/ms745781.aspx
There is also a control that lets you do the reverse: host Windows Forms content from within WPF:
http://nayyeri.net/host-windows-forms-controls-in-wpf
Between the two, you can move the 'dividing line' between WPF and Windows Forms with some degree of flexibility.
There is at one caveat you'll need to keep in mind. Windows Forms works internally in terms of HWND's... a window managed by the legacy Windows window manager (which handles the z-order). WPF doesn't do this... A WPF tree is typically rendered into a single HWND', and it's WPF that manages things like z-order. What this means to you is that z-order doesn't always work the way you expect it to, and there are things you can't do with hosted Windows Forms controls that you can do with traditional WPF elements. (There is actually a way to solve this, but it involves periodically rendering the HWND into a memory bitmap, rendering that bitmap into a WPF surface, and then redirecting events directed to the WPF surface to the underlying HWND. This is powerful, but tricky and difficult to get right.)
I see no objection to do that.(I have in WinForms Application WPF windows)
Many of the examples used MessageBox.Show which is part of the Windows.Forms.
Of course you must rewrite all windows, not only controls.
I'm creating a HUD window for inspecting biz entities in my WinForms application.
I wanted to have a completely different style of window (minimize the content area and showing only the TitleBar, no system buttons, etc) so I created a WPF application for this.
The problem is that I want this Window to 'live' inside my WinForms application. I can't just add the WPF as an OwnedForm or set the main Form as the Owner of the WPF window.
So, how can achive this?
EDIT: Thanks to pst I found the answer. Here is the snippet:
System.Windows.Forms.Integration.ElementHost.EnableModelessKeyboardInterop(_inspector);
WindowInteropHelper inspectorHelper = new WindowInteropHelper(_inspector);
inspectorHelper.Owner = this.Handle;
_inspector.Show();
A WPF Window has a Win32-window handle/context.
See WindowInteropHelper. You can use this with Win32 (or perhaps there is WinForms support?) to set the owner window of the WPF Window. Be aware the handle does not exist until the "source initialized" (?) event.
However, using just WinForms, you may be able to customize the titlebar as much as you need (you can overwrite the drawing itself via Win32, and I think you lose all the control boxes without going this far).
There are lots of google results on this topic if you use the correct keywords.
I want to use WPF windows in a legacy win32 application.
I'd like to behave them in a similar way, like the WPF window always being displayed on top of the win32 window.
For this I'd like to set the owner of the WPF window to the win32 windows, but I got no idea how to achieve this.
Any help here?
Since the answer is hidden behind some link, here the code that did the trick:
System::Windows::Interop::WindowInteropHelper^ helper = gcnew System::Windows::Interop::WindowInteropHelper(myWpfChildWindow);
helper->Owner = (System::IntPtr)myMainWindowHWND;
This article shows how to get the handles for both as well as how to make the WPF window become a transparent overlay for the win32 window.
http://dedjo.blogspot.com/2007/04/transparent-wpf-control-over-unmanaged.html
This article uses a WindowInteropHelper to accomplish similar functionality.
http://blogs.msdn.com/wpfsdk/archive/2007/04/03/centering-wpf-windows-with-wpf-and-non-wpf-owner-windows.aspx
MSDN page on WindowInteropHelper:
http://msdn.microsoft.com/en-us/library/system.windows.interop.windowinterophelper.aspx
Hope that helps,
Ed
How about SetParent()? I know works when making a WPF window an MDI Child of a Windows Form.