I am having trouble finding a way to force any display resolution/timing I want in my C# program. I am running Windows 7 with a GeForce 210 graphics card. My current method to achieve these custom resolutions is to use the driver GUI to manually add the custom resolutions and then use Windows calls to change to those resolutions but I need a way to add new custom resolutions in real time. I have looked into the NVAPI but I was not able to find a way to do this. I also looked into the command line tool for the graphics driver but I was not able to get it to work. My last resort is to rewrite the values in registry but I would really like to avoid that. I am willing to use a different programming language or a third party tool as long as I can invoke it from the command line via my program. Can anyone point me in the right direction?
Thanks in advance.
Update (8/16/2011):
I have been working on this problem with NVIDIA and they are providing me with an advanced NVAPI that will allow me to recreate the functionality of their driver. They also confirmed that the basic version of NVAPI that they provide will not do this.
You could try using ChangeDisplaySettings
I'm not sure if it will have all the options provided by the nvidia panel, but certainly the basics like resolution, refresh rate, screen orientation, etc. I've used it myself in the past to dynamically change screen orientation (rotate to landscape/portrait) on a click of a button.
I was able to solve this problem by using the NDA version of the NVAPI. It still was not trivial but all of the tools are there.
Related
I've searched a lot these days to find a way to programmatically hide or disable the start button in Windows 8.1, but could not find any useful information
Is there any way to do this? Either with C# or with some registry-keys...
A short explanation why I need to hide the button:
We have a .NET Desktop Application which runs on WinXP, Vista and 7 in a self-made kiosk mode. Now we have to get it running in Win8 (8.1) but as expected, the new Start-Menu (Metro, Modern UI, whatever you call it) is always there.
I already managed to disable the Hot Corners, but the Start Button in the left corner still appears when you move you mouse over it, and it also starts the Metro - what we don't want.
Any help would be appreciated!
It seems that there is no such way...
But you could use a third party tool like one of these http://lifehacker.com/how-can-i-hide-the-start-button-in-windows-8-1-1478012124.
This question belongs on SuperUser, since it's not code related, but I'll have a go at it.. You should create a system account with an assigned access. Here, read these two articles: first second
According to these articles, it shouldn't take you more than 5 minutes to achieve what you want.
... find a way to programmatically hide or disable the start button in Windows 8.1...
See Registry Key Controlling Start Button in Windows 8.1? on SuperUser. According to one commentor, there is no simple fix like a registry key. Tools like 7+ Taskbar Tweaker inject a DLL into explorer hook/subclass/redirect some of its methods.
If you are going to write your own DLL and inject it into Explorer, then you might want to take a look at Microsoft's Detours Library. I've used it in the past and its actually easy to use. The description from the website: Detours intercepts Win32 functions by re-writing the in-memory code for target functions. The Detours package also contains utilities to attach arbitrary DLLs and data segments to any Win32 binary.
I'm writing a small c# program, I don't want the final user to take screenshots while using my program, is it possible? Or even if he takes one, how can I know it?
Thanks in advance and sorry if this is a poor-content question due to my lack of experience in c# coding.
You can create a system-wide keyboard hook using the low-level keyboard filter and cancel any printscreen keyboard combination. But if someone has also installed a helper application (like Gadwin or something) it'll become a lot more difficult because you won't know beforehand what keyboard shortcut you should catch (most tools allow to specify your own hooks).
Here's an article on using hooks in C#
and here's a ready-made keyboard hook library for .net that uses global mouse and keyboard hooks (use Google to find more freeware and commercial libraries and tools).
On a side note: it's generally not preferred to change the system behavior. Screenshots are system behavior and serve a distinguished purpose for trouble shooting. If you prevent this, users will not be able to show you a screenshot of something wrong. But if you must do it, you can do it.
EDIT: on a deeper level, you can install an API hook. All screenshot applications use API calls to get the content of a (part of) the screen. But API hooks are hard to get right. A more trivial way is probably by writing a user-level driver. While you can prevent all this, it is really worth all the trouble?
You might want a keyboard hook. But it'll tell you if the user pressed the "print screen" key, not if someone programmatically take a screenshot using some GDI function.
I doubt it's possible to prevent all the ways of taking a screenshot.
General answer: No. It's not possible to detect this - especially from C#. There are dozens of ways to take screenshot and even applications written in C++/WinAPI can only detect some of them, but not all.
Also consider - what if user is running your app in virtual machine? He'll be able to take screenshots at host machine and you can do absolutely nothing to detect (not even prevent) this.
Does anyone know how to apply effects to the entire screen, in c# or any programming language.
I'm mostly interested in making the screen monochrome (specifically green-white instead of black white).
I know a cross-graphic card solution is possible because I found a program that can do it:
http://www.freedomscientific.com/products/lv/magic-bl-product-page.asp
Anyone knows how to accomplish something this or where to look?
Thanks !!
There is no easy Windows API to modify the entire screen contents. But this could be done at the device driver level.
Otherwise you have to resort to some Windows API tricks: place a "fake" window over the entire desktop, in a loop: grab the entire screen contents without grabbing fake window contents, do your processing to get the monochrome effect, then display that on the fake window. Yes, it's hacky and slow, but possible. Even more hacky, when you get mouse clicks to "go through" the fake window (lots of SetWindowsRgn calls).
So cross-platform here means using GDI, though some older DirectDraw APIs might work, in that case, you have a much easier time with hardware overlays (and better performance). Though I'm not sure how many cards actually support hardware overlays, and if newer versions of windows support the older DirectDraw APIs.
One more possibility is if the video card has a C# or C++ or C API, then you can do whatever you want with the card without writing device driver code.
Then there's CUDA, but I haven't yet tried that out. I know it's for stream processing on nVidia boards, but I wonder if it could get you an easy backdoor into the video display stuff.
To help people in the future who are interested in this:
This is possible with the Magnification API's color effect method. This allows one to use a matrix that can be applied to the whole screen.
NegativeScreen is an open source project that implements the feature you are describing in C#.
Unfortunately, this only works with affine transformations, as the API takes only an augmented matrices rather than a delegate or something.
OK, I know there are quite a few posts on this topic. However, none of them provide the solution to my issue: I don't want just to turn off my monitor(s), I wish my code to turn off a specific monitor. The URL the most people refer to, http://fci-h.blogspot.com/2007/03/turn-off-your-monitor-via-code-c.html, doesn't help here, as it turns off all the displays.
So, I have my laptop screen and an additional external monitor. While I'm watching movies, I switch the display to the external monitor and my laptop screen goes black, however, it's still on and glowing in the dark. I wish to turn it off. Could anyone help please?
EDIT: Is there any way to acomplish this, meaning it needn't have to be written in .Net. Basically, I just need an .exe file that's able to turn the particular monitor off and on alternately.
It looks like there's no good way of turning off a specific monitor, but it is possible to set your laptop's backlight to minimum brightness. Depending on which version of Windows you have, there are different ways to do it:
send IOCTL_VIDEO_SET_DISPLAY_BRIGHTNESS I/O control as described here: http://msdn.microsoft.com/en-us/magazine/dvdarchive/cc163415.aspx
use WMI method WmiSetBrightness as described here: What API call would I use to change brightness of laptop (.NET)?
use Win API SetMonitorBrightness, but I don't know of anybody who has done it in C#.
My webcam has a button, with which you take a photo of current frame
when using it's original software what came with it when I bought it.
Is there any way to use that button to take photos in my program.
I would be using C#.
I was thinking of using Windows Image Acquisition (WIA) or avicap32
for using webcam in my software.
Any help would be appreciated. Where do I start?
EDIT:
I see that you didn't understand me. I need to know if my phisycal camera button is pressed.
I am using DigiMicro 1.3 camera (Manufacturer is DNT), which isn't really a webcam but a USB microscope, but
it behaves like a webcam.
Does the camera actually require that the software be running when you press the button? I know some webcams implement this feature at the driver level. If that's the case, I don't think there's much you can do without interacting directly with the USB port, which would be incredibly difficult and likely not worth the trouble. I can't find any technical documentation on the vendor's website with that kind of information.
The "MicroCapture" software doesn't come with any DLLs that have exported functions, so P/Invoking doesn't appear to be an option. Unfortunately, I can't get the driver installed, so I can't check if it comes with any P/Invoke-able DLLs.
Sorry, but since there's no standard interface for that kind of functionality and the vendor doesn't provide any specific information on it, I don't think this is possible. I would suggest contacting DNT directly about it. They may have some component that will do what you need.
This Coding4Fun post guides you through pretty much everything you need to do to get started using WIA, including adding the reference to a project, displaying the select a device dialog, and of course actually taking the picture :P.
Coding4Fun - Look at me! Windows Image Acquisition
I suggest that you take a look at the DirectShow.NET library. It has great functionality for capturing images/videos off connected devices. It also comes with several samples to get you started quickly.