screenshot bugs

[JoeQinOvO]

the screenshot doesn't seem to get my whole screen

[urbanknight]

This happened if the user changed the display scaling. To solve this you need to calculate the actual screen size with that change.

[DllImport("gdi32.dll", CharSet = CharSet.Auto, SetLastError = true, ExactSpelling = true)]
    public static extern int GetDeviceCaps(IntPtr hDC, int nIndex);

    public enum DeviceCap
    {
        VERTRES = 10,
        DESKTOPVERTRES = 117
    }

    public static double GetWindowsScreenScalingFactor(bool percentage = true)
    {
        //Create Graphics object from the current windows handle
        Graphics GraphicsObject = Graphics.FromHwnd(IntPtr.Zero);
        //Get Handle to the device context associated with this Graphics object
        IntPtr DeviceContextHandle = GraphicsObject.GetHdc();
        //Call GetDeviceCaps with the Handle to retrieve the Screen Height
        int LogicalScreenHeight = GetDeviceCaps(DeviceContextHandle, (int)DeviceCap.VERTRES);
        int PhysicalScreenHeight = GetDeviceCaps(DeviceContextHandle, (int)DeviceCap.DESKTOPVERTRES);
        //Divide the Screen Heights to get the scaling factor and round it to two decimals
        double ScreenScalingFactor = Math.Round(PhysicalScreenHeight / (double)LogicalScreenHeight, 2);
        //If requested as percentage - convert it
        if (percentage)
        {
            ScreenScalingFactor *= 100.0;
        }
        //Release the Handle and Dispose of the GraphicsObject object
        GraphicsObject.ReleaseHdc(DeviceContextHandle);
        GraphicsObject.Dispose();
        //Return the Scaling Factor
        return ScreenScalingFactor;
    }
    public static Size GetDisplayResolution()
    {
        var sf = GetWindowsScreenScalingFactor(false);
        var screenWidth = Screen.PrimaryScreen.Bounds.Width * sf;
        var screenHeight = Screen.PrimaryScreen.Bounds.Height * sf;
        return new Size((int)screenWidth, (int)screenHeight);
    } 

and you can use it like this:

var size = GetDisplayResolution();

and for better stealthy way use WinAPI to take the screenshot because "CopyFromScreen" will raise a flag by most AVs