Trying to Understand Windows Forms and Threading in C# - c#

Recently I’ve been working on a windows wallpaper manager. It will scan multiple directories for images and have a settings window to customize. In addition, I want to bypass the built-in wallpaper and instead use a windows form based off the ideas discussed here: Setting a Windows form to be bottommost to allow for greater control over image placement. I have built the file operations to find the wallpapers, and various other support operations.
However, I am stumped on how to implement a windows form properly. Not just the one in the Stack Overflow post above. So far none of my CompSci classes (7 so far) have discussed GUIs, and thus I have no knowledge to work from. I turned to the internet to learn how to work with GUIs. While I learned plenty to start a thread, or show a form, I was never able to find anything that described the proper way to engineer an application with a GUI. All I have learned in respect to engineering the application is to limit the number of threads, and try to separate the GUI from the non-GUI related code (if that makes sense).
Like I have said, I have no clue what I am doing. If someone would be willing to give me pointers or even a link to something on this subject, that would be amazing!
EDIT: I have been using this as a learning exercise, and I have mostly been learning from trial and error, probably mostly error

To draw on the true desktop, you need to get a handle to it: GetDesktopWindow is the function to use. But to change the wallpaper you do not draw on the desktop, but instead you use the dedicated API for handling the desktop wallpaper: SystemParametersInfo(SPI_SETDESKWALLPAPER, ...). There is also the legacy COM Shell interface, IActiveDesktop and IActiveDesktop::SetWallpaper.
As you can see, none of the APIs to manipulate the desktop and the wallpaper are managed (C#, .Net) so you will have to jump through some hoops to get this working from C#. If your goal is to learn C# style UI, I would recommend to stick to the 'blessed' way of doing this (winforms, WPF etc) and do not try to jump straight to p-Invoke and COM interop. Perhaps you can pick another project, eg. display the images/pictures in a carousel in a form.
If you're curious still, Google for C# and SystemParametersInfo or IActiveDesktop and you'll find examples of how to do this from managed C#, many examples right here on StackOverflow.
Bonus: of course Raymond Chen has a blog on this topic: How do I put a different wallpaper on each monitor?.

Related

Windows 8 DirectX SwapChainBackgroundPanel Questions

I come from two distinct backgrounds: I have much experience with WPF/XAML/C# app development and equal experience with C++/DirectX development. I hear about the ability to use DirectX and XAML together and I get all excited, but now I have hit this wall.
I'm trying to use the SwapChainBackgroundPanel in a WPF application. But I'm trying to use C# as the underlying language. I keep running into issues where, regardless of the type of C# project I create (PCL, WPF, Windows Store) none of these types are defined [namely I've been looking for SwapChainBackgroundPanel and some other DX stuff like the device and etc.)
So my question is: how does this work in C#? I've seen the simple shooter example from the MSDN done in C++ and it makes sense; I get it. But I feel like I'm missing one of those "gotcha's" when trying to do it in C#.
Any advice, or maybe a link to an example, or at best a little tutorial on setting up a C#/XAML/DX app would be amazing. Thanks everyone.
There is no SwapChainBackgroundPanel available to a WPF app (that is in PresentationCore). The closest you are going to get is the D3DImage class, but it's not exactly the same. See this discussion.
I don't think you can fully utilize the DirectX capabilities of a Windows 8 Store app (SwapChainBackgroundPanel) from C#. You're going to have to do your DirectX work in C++ as in the example you described. You can certainly combine the three (Xaml, C#, C++) as in this example, but I don't think a 100% C# app is possible.
The answer is wrong. It is possible to fully utilize C# throught a wrapper.
I did this myself with SharpDx which is actually one of the microsoft recommendations to use DirectX in C#.
As for the choice of XAML Library, Universal Windows App 10 or Windows Store App 8 is the way to go. Use a SwapChainPanel instead of SwapChainBackgroundPanel.

Capture visual output of a DirectX application - even in background?

I need to capture the visual output (like a screenshot) of a DirectX window.
Currently, I use this approach.
But, when the window is in background, it captures whatever is in front of it.
I see that DirectX windows render even when minimized or in background, so this should be possible.
But, how? (It also needs to be fast, and it needs to work on Windows XP too, unfortunately...)
Edit: I am very busy these days... Don't worry, I'll put the bounty back if it expires.
To capture Direct3D windows that are in the background (or moved off screen), I believe you have the following options:
Inject and hook Direct3D within the target application via the link you have already posted or this more up-to-date example (EasyHook can be difficult to get setup but it does work really well) - you can always ask for help about getting it working. I have used that technique for capturing in a number of games without issues (most recently for an ambilight-clone project). The problem with this approach is your concern about game protection causing bans, however FRAPs also uses hooking to achieve this, so perhaps your concerns are exaggerated? I guess gamers being banned for a screen shot is an expensive way of finding out.
For windowed applications on Vista/Win 7 - you could inject and hook the DWM and make your capture requests through its shared surface. I have had this working on Vista, but have not finished getting it working on Windows 7, here is an example of it working for Windows 7 http://www.youtube.com/watch?v=G75WKeXqXkc. The main problem with this approach is the use of undocumented API's which could mean your application breaks without any warning upon a windows patch release - also you would have to redo the technique for each new major Windows flavour. This also does not address your need to capture in Windows XP.
Also within the DWM, there is a thumbnail API. This has limitations depending on what your trying to do. There is some information on this API along with other DWM API's here http://blogs.msdn.com/b/greg_schechter/archive/2006/09/14/753605.aspx
There are other techniques for intercepting the Direct3D calls without using EasyHook, such as substituting the various DLL's with wrappers. You will find various other game hooking/interception techniques here: http://www.gamedeception.net/
Simply bring the Direct3D application to the foreground (which I guess is undesirable in your situation) - this wouldn't work for off-screen windows unless you also move the window.
Unfortunately the only solution for Windows XP that I can think of is intercepting the Direct3D API in some form.
Just a clarification on Direct3D rendering while minimised. During my fairly limited testing on this matter I have found this to be application dependant; it is generally not recommended that rendering take place while the application is minimized (also this reference), it does continue to render while in the background however.
UPDATED: provided additional link to more up-to-date injection example for point 1.
A quick google and i found this Code Project which relates to Windows XP. I dont know if you can apply this knowledge to Windows Vista and 7??
http://www.codeproject.com/Articles/5051/Various-methods-for-capturing-the-screen
EDIT:
I found this article as well:
http://www.codeproject.com/Articles/20651/Capturing-Minimized-Window-A-Kid-s-Trick
This links off from Justins blog post here from the comments. It seems he was working on this with someone (i see thats your link about).
http://spazzarama.com/2009/02/07/screencapture-with-direct3d/
The code that you linked to (from spazzarama), which you said you were using in your project, captures the front buffer of your DirectX device. Have you tried capturing the back buffer instead? Going from the code on your linked site, you would change line 90 from
device.GetFrontBufferData(0, surface);
to
Surface backbuffer = device.GetBackBuffer(0, 0, BackBufferType.Mono);
SurfaceLoader.Save("Screenshot.bmp", ImageFileFormat.Bmp, backbuffer);
This would also involve removing lines 96-98 in your linked example. The backbuffer might be generated without the obstructing window.
EDIT
Nevermind all of that. I just realized that your linked sample code is using the window handle to define a region of the screen, and not actually doing anything with the DirectX window. Your sample code won't work around the obstruction because your region is already drawn with the other window in front of it by the time you access it.
Your best bet to salvage the application is probably to bring the DirectX window to the top of the screen before running the code to capture the image. You can use the Wind32API BringWindowToTop function to do that (http://msdn.microsoft.com/en-us/library/ms632673%28VS.85%29.aspx).

How to make a winform open like Mac OS animation?

Could any one tell how can I open a form with an animation similar to the one used by Mac-OS launcher. I have seen a few other software doing the same thing. For eg: This youtube video also shows a demo of it (#Time: 20 sec and #Time: 28 sec).
I know of animateWindow API, but I think this is not possible with animateWindow.
Any idea on how to do this?
AnimateWindow won't fit the bill.
In my opinion these programs work by
Creating a transparent window when needed, while computing icons to display
Creating the animation and displaying it on the transparent window device context
Handling everything on the window via custom events.
What you need is
a comprehensive knowledge of GDI32
an equally comprehensive knowledge of those dirty tricks used to create animations programmatically.
I'm sorry, but I think that this is not the kind of topic that can briefly explained on a single answer :-(
Eventually, you need something that augments and extends Windows's native graphic capabilities. There are companies that did this before: IIRC Serif.com did write their own GDI replacement for their DTP programs, and I think that all of these companies that make desktop enhancements did the same (or at least, they know how to squeeze GDI32 capabilities)
You could try WPF or SilverLight or mixure of above to meet your requirements.
You can check Good WPF or silverlight windows gadget examples and let me know.

Alternative of WebBrowser for 3D Animation in WPF by C#

I am not able to apply 3D effects on WPF's built-in WebBrowser, because it is just a thin wrapper around the native ActiveX-Webbrowser, which isn't based on WPF. I saw most of the places people suggested about one Link ,but I m not able to make it work in my application and it is having so many dlls which I don't want. Can anybody suggest me any other good alternative solution present then?
Maybe you forget to copy the needed awesomium.dll & AwesomiumProcess.exe with your executing assembly (which are not .Net assemblies).
I also have some difficulties to run with awesomium but it's not impossible.
I can recommand you the Troymium/TroymiumNet which is actively maintain by its developers.
I use it on Microsoft Surface to connect people to their facebook account.
I've never used it, but you could try Berkelium with berkelium-sharp.

Good framework for a C# developer to use for visually stunning presentation layer

I am about to write a front end app, which will be used as a media center app. It will plug directly into a high definition TV. Essentially transforming my laptop into a media player. While this concept is not new, I want custom functionality, so this is why I am not reusing existing products.
I'm a C# developer, so the app should ideally be written in C#. And there is 1 other consideration, I need to accept input via the MCE Remote.
I was considering using Silverlight for this. Would you recommend this? Or any other recommendations for frameworks before I begin planning around this.
Thanks in advance.
This is the type of stuff that the Windows Presentation Foundation was meant for. You'll get a lot more access to the hardware than Silverlight would provide (I.E. that MCE remote you mentioned). You mark up your UI with vector graphics/XAML, and then perform the logic with C#.
EDIT: WPF also has support out of the box for animations which can make your UI a lot more interactive.
EDIT 2: Scott Hanselman has written a really cool application called BabySmash and posted the source online. It basically intercepts keyboard input and shows shapes and sounds on the computer. It's a good "child-proofing" method for your PC. The code could provide you with some insight into WPF and how to do the animations and interactivity that you're looking for.
Is this a desktop app? If so I would use WPF. Silverlight is a subset of WPF, so using WPF you could potentially do more.
Silverlight or WPF, if you want some extra power. Both have a similar programming model (with XAML and code-behind) so you might be able to start with Silverlight and move up to WPF if you need.
The VLC api might be useful for playing your media, someone has created a C# wrapper for it:
http://wiki.videolan.org/.Net_Interface_to_VLC
WPF is certainly the way to go, and for playing media check out the excellent WPF MediaKit: http://wpfmediakit.codeplex.com/ I've used it successfully in many projects.

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