How to get the resolution of the screen in which a user control is opened?

I wanted to know the resolution of the screen and I have read this question:Get and Set Screen Resolution

However, it seems this give the resolution of the primary screen, but I would like to know if there is some way to get the resolution of the screen in which is shown the window.

For example, I have to screens, the laptop screen and a monitor. The laptop has a resolution of 1366x768 and the monitor has a resolution of 1920x1080. The main screen is the monitor, and the screen of the laptop is the secondary screen.

I would like to have a simple application that it has a button, and I would like than when I click the button, it gives the resolution of the monitor in which I am seeing the window. If I drag the window to the other monitor, then it should give me the resolution of the other monitor.

Thanks.

1 Answer

You can accomplish it by various ways but I like straightforward way using MonitorFromRect and GetMonitorInfo functions. Assuming you set proper app.manifest for Per-Monitor DPI, the following extension method will work to get screen Rect from a FrameworkElement.

Regarding the point jwdonahue raised, this method will return the Rect of screen which has the largest intersection with the specified FrameworkElement.

using System;
using System.Runtime.InteropServices;
using System.Windows;
using System.Windows.Media;
public static class ScreenHelper
{ public static Rect ToScreenRect(this FrameworkElement element) => GetMonitorRect(GetElementRect(element)); private static Rect GetElementRect(FrameworkElement element) { var point = element.PointToScreen(new Point(0, 0)); var dpi = VisualTreeHelper.GetDpi(element); return new Rect(point, new Size(element.ActualWidth * dpi.DpiScaleX, element.ActualHeight * dpi.DpiScaleY)); } private static Rect GetMonitorRect(Rect elementRect) { RECT rect = elementRect; var monitorHandle = MonitorFromRect(ref rect, MONITOR_DEFAULTTONULL); if (monitorHandle != IntPtr.Zero) { var monitorInfo = new MONITORINFO { cbSize = (uint)Marshal.SizeOf<MONITORINFO>() }; if (GetMonitorInfo(monitorHandle, ref monitorInfo)) { return monitorInfo.rcMonitor; } } return Rect.Empty; } [DllImport("User32.dll")] private static extern IntPtr MonitorFromRect(ref RECT lprc, uint dwFlags); private const uint MONITOR_DEFAULTTONULL = 0x00000000; [DllImport("User32.dll")] [return: MarshalAs(UnmanagedType.Bool)] private static extern bool GetMonitorInfo(IntPtr hMonitor, ref MONITORINFO lpmi); [StructLayout(LayoutKind.Sequential)] private struct MONITORINFO { public uint cbSize; public RECT rcMonitor; public RECT rcWork; public uint dwFlags; } [StructLayout(LayoutKind.Sequential)] private struct RECT { public int left; public int top; public int right; public int bottom; public static implicit operator Rect(RECT rect) { return new Rect( rect.left, rect.top, rect.right - rect.left, rect.bottom - rect.top); } public static implicit operator RECT(Rect rect) { return new RECT { left = (int)rect.X, top = (int)rect.Y, right = (int)rect.Right, bottom = (int)rect.Bottom }; } }
}