How to Take a Screenshot in a Windows Application

Capture screenshot of active window?

ScreenCapture sc = new ScreenCapture();
// capture entire screen, and save it to a file
Image img = sc.CaptureScreen();
// display image in a Picture control named imageDisplay
this.imageDisplay.Image = img;
// capture this window, and save it
sc.CaptureWindowToFile(this.Handle,"C:\\temp2.gif",ImageFormat.Gif);

http://www.developerfusion.com/code/4630/capture-a-screen-shot/

How can I take a screenshot in a windows application?

HDC hScreenDC = GetDC(nullptr); // CreateDC("DISPLAY",nullptr,nullptr,nullptr);
HDC hMemoryDC = CreateCompatibleDC(hScreenDC);
int width = GetDeviceCaps(hScreenDC,HORZRES);
int height = GetDeviceCaps(hScreenDC,VERTRES);
HBITMAP hBitmap = CreateCompatibleBitmap(hScreenDC,width,height);
HBITMAP hOldBitmap = static_cast<HBITMAP>(SelectObject(hMemoryDC,hBitmap));
BitBlt(hMemoryDC,0,0,width,height,hScreenDC,0,0,SRCCOPY);
hBitmap = static_cast<HBITMAP>(SelectObject(hMemoryDC,hOldBitmap));
DeleteDC(hMemoryDC);
DeleteDC(hScreenDC);

Get a screenshot of a specific application

Here's some code to get you started:

public void CaptureApplication(string procName)
{
    var proc = Process.GetProcessesByName(procName)[0];
    var rect = new User32.Rect();
    User32.GetWindowRect(proc.MainWindowHandle, ref rect);

    int width = rect.right - rect.left;
    int height = rect.bottom - rect.top;

    var bmp = new Bitmap(width, height, PixelFormat.Format32bppArgb);
    using (Graphics graphics = Graphics.FromImage(bmp))
    {
        graphics.CopyFromScreen(rect.left, rect.top, 0, 0, new Size(width, height), CopyPixelOperation.SourceCopy);
    }

    bmp.Save("c:\\tmp\\test.png", ImageFormat.Png);
}

private class User32
{
    [StructLayout(LayoutKind.Sequential)]
    public struct Rect
    {
        public int left;
        public int top;
        public int right;
        public int bottom;
    }

    [DllImport("user32.dll")]
    public static extern IntPtr GetWindowRect(IntPtr hWnd, ref Rect rect);
}

It works, but needs improvement:

You may want to use a different mechanism to get the process handle (or at least do some defensive coding)
If your target window isn't in the foreground, you'll end up with a screenshot that's the right size/position, but will just be filled with whatever is in the foreground (you probably want to pull the given window into the foreground first)
You probably want to do something other than just save the bmp to a temp directory

How to get the screenshot of the form

Even simpler answer supported by .NET:

Control.DrawToBitmap.

Best way to take screenshot in windows 10

I accidently found a easy way to take screenshot of my screen in windows 10.

Just hold Windows Logo Key + Shift Key + S

Sample Image

Than you can select what part of the screen you want to take the screenshot.
This will copy of a selected part to your clipboard and than you can simply past it in Paint, photoshop or any image app you want.

Thanks @Abhi

There are many other ways to do this as well:

1. Snipping Tool : Start > All Programs > Windows Accessories > Snipping Tool.

2. Windows Key + Print Screen : Windows Key + PrtScn.

How to take Screen shot in windows store apps

You can capture you screen using RenderTargetBitmap. Try this code:

//create and capture Window
var renderTargetBitmap = new RenderTargetBitmap();
await renderTargetBitmap.RenderAsync(Window.Current.Content);

//create unique file in LocalFolder
var file = await ApplicationData.Current.LocalFolder.CreateFileAsync("screenshotCapture.jpg", CreationCollisionOption.GenerateUniqueName);

//create JPEG image 
using (var stream = await file.OpenStreamForWriteAsync())
{
    var logicalDpi = DisplayInformation.GetForCurrentView().LogicalDpi;
    var pixelBuffer = await renderTargetBitmap.GetPixelsAsync();
    var encoder = await BitmapEncoder.CreateAsync(BitmapEncoder.JpegEncoderId, stream.AsRandomAccessStream());
    encoder.SetPixelData(BitmapPixelFormat.Bgra8,
                            BitmapAlphaMode.Straight,
                            (uint)renderTargetBitmap.PixelWidth,
                            (uint)renderTargetBitmap.PixelHeight, logicalDpi, logicalDpi,
                            pixelBuffer.ToArray());
    await encoder.FlushAsync();
}