How can I find the position of a maximized window?

Question

I need to know the position of a window that is maximized.

WPF Window has Top and Left properties that specifies the window\'s location. However, if you maximize the

Answer 1

I realize that you are working in WPF, and this answer makes use of Forms technology, but it should work without much difficulty.

You can get a collection of the screens through My.Settings.Screens.AllScreens. From there you can access the resolution that the screen is currently working on.

Since WPF windows retain the Top/Left values that they had when they were maximized, then you can determine which screen they are on by figuring out which screen that Top/Left coordinates refer to, and then get the top/left coordinate for that screen.

Unfortunately, I am on the road, and can't test this at the moment. If you do implement, I would love to see what you come up with.

Answer 2

Here's the solution I came up with based on previous discussion here (thanks!).

This solution...

• returns the position of a window in its current state
• handles all window states (maximized, minimized, restored)
• does not depend on Windows Forms (but is inspired by it)
• uses the window handle to reliably determine the correct monitor

The main method GetAbsolutePosition is implemented here as an extension method. If you have a Window called myWindow, call it like this:

Point p = myWindow.GetAbsolutePosition();

Here's the complete code:

using System;
using System.Windows;
using System.Windows.Interop;
using System.Runtime.InteropServices;

static class OSInterop
{
    [DllImport("user32.dll")]
    public static extern int GetSystemMetrics(int smIndex);
    public const int SM_CMONITORS = 80;

    [DllImport("user32.dll")]
    public static extern bool SystemParametersInfo(int nAction, int nParam, ref RECT rc, int nUpdate);

    [DllImport("user32.dll", CharSet = CharSet.Auto)]
    public static extern bool GetMonitorInfo(HandleRef hmonitor, [In, Out] MONITORINFOEX info);

    [DllImport("user32.dll")]
    public static extern IntPtr MonitorFromWindow(HandleRef handle, int flags);

    public struct RECT
    {
        public int left;
        public int top;
        public int right;
        public int bottom;
        public int width { get { return right - left; } }
        public int height { get { return bottom - top; } }
    }

    [StructLayout(LayoutKind.Sequential, Pack = 4, CharSet = CharSet.Auto)]
    public class MONITORINFOEX
    {
        public int cbSize = Marshal.SizeOf(typeof(MONITORINFOEX));
        public RECT rcMonitor = new RECT();
        public RECT rcWork = new RECT();
        [MarshalAs(UnmanagedType.ByValArray, SizeConst = 32)]
        public char[] szDevice = new char[32];
        public int dwFlags;
    }
}

static class WPFExtensionMethods
{
    public static Point GetAbsolutePosition(this Window w)
    {
        if (w.WindowState != WindowState.Maximized)
            return new Point(w.Left, w.Top);

        Int32Rect r;
        bool multimonSupported = OSInterop.GetSystemMetrics(OSInterop.SM_CMONITORS) != 0;
        if (!multimonSupported)
        {
            OSInterop.RECT rc = new OSInterop.RECT();
            OSInterop.SystemParametersInfo(48, 0, ref rc, 0);
            r = new Int32Rect(rc.left, rc.top, rc.width, rc.height);
        }
        else
        {
            WindowInteropHelper helper = new WindowInteropHelper(w);
            IntPtr hmonitor = OSInterop.MonitorFromWindow(new HandleRef((object)null, helper.EnsureHandle()), 2);
            OSInterop.MONITORINFOEX info = new OSInterop.MONITORINFOEX();
            OSInterop.GetMonitorInfo(new HandleRef((object)null, hmonitor), info);
            r = new Int32Rect(info.rcWork.left, info.rcWork.top, info.rcWork.width, info.rcWork.height);
        }
        return new Point(r.X, r.Y);
    }
}

Answer 3

I finally found a solution working for me:

private System.Drawing.Rectangle getWindowRectangle()
{
    System.Drawing.Rectangle windowRectangle;

    if (this.WindowState == System.Windows.WindowState.Maximized)
    {
        /* Here is the magic:
         * Use Winforms code to find the Available space on the
         * screen that contained the window 
         * just before it was maximized
         * (Left, Top have their values from Normal WindowState)
         */
        windowRectangle = System.Windows.Forms.Screen.GetWorkingArea(
            new System.Drawing.Point((int)this.Left, (int)this.Top));
    }
    else
    {
        windowRectangle = new System.Drawing.Rectangle(
            (int)this.Left, (int)this.Top,
            (int)this.ActualWidth, (int)this.ActualHeight);
    }

    return windowRectangle;
}

Answer 4

Universal one line answer working for all monitors and all high DPI variants:

Point leftTop = this.PointToScreen(new Point(0, 0));

This for example returns (-8, -8) for a window which is maximized on a 1920 wide screen whose ActualWidth returns 1936.

Just a rant to the other answers: NEVER mix up logical 96 dpi WPF pixels (using double) with native real pixels (using int) - especially by just casting double to int!

Answer 5

public static System.Drawing.Rectangle GetWindowRectangle(this Window w)
{
    if (w.WindowState == WindowState.Maximized) {
        var handle = new System.Windows.Interop.WindowInteropHelper(w).Handle;
        var screen = System.Windows.Forms.Screen.FromHandle(handle);
        return screen.WorkingArea;
    }
    else {
        return new System.Drawing.Rectangle(
            (int)w.Left, (int)w.Top, 
            (int)w.ActualWidth, (int)w.ActualHeight);
    }
}

Answer 6

This seems to be a problem with System.Windows.Window!!!

Maximized window give unreliable values for Left, Width, ActualWidth, Top, Height and ActualHeight.

After maximizing a window, it can often keep the Left and Width values from the pre-maximized window.

For others reading - there is no problem when the window is un-maximized.

Also, what I find odd is that the values you read are in WPF DPI coordinates, [i.e. 1936x1096, from (-8, -8) to (1928, 1088)], but when you set these values you have to use screen pixel coordinates, [i.e. 1920x1080, using (0,0) etc...]

@tgr provided a reliable partial solution above, which I've improved below:

• Fixing intellisense for extension methods by moving helper class to sub class
• creating GetAbsoluteRect() method to provide Width/Height and point all in one call
• refactoring common code

Here's the C# solution:

using System;
using System.Runtime.InteropServices;
using System.Windows;
using System.Windows.Interop;

public static partial class Extensions
{
    static class OSInterop
    {
        [DllImport("user32.dll")]
        public static extern int GetSystemMetrics(int smIndex);
        public const int SM_CMONITORS = 80;

        [DllImport("user32.dll")]
        public static extern bool SystemParametersInfo(int nAction, int nParam, ref RECT rc, int nUpdate);

        [DllImport("user32.dll", CharSet = CharSet.Auto)]
        public static extern bool GetMonitorInfo(HandleRef hmonitor, [In, Out] MONITORINFOEX info);

        [DllImport("user32.dll")]
        public static extern IntPtr MonitorFromWindow(HandleRef handle, int flags);

        public struct RECT
        {
            public int left;
            public int top;
            public int right;
            public int bottom;
            public int width { get { return right - left; } }
            public int height { get { return bottom - top; } }
        }

        [StructLayout(LayoutKind.Sequential, Pack = 4, CharSet = CharSet.Auto)]
        public class MONITORINFOEX
        {
            public int cbSize = Marshal.SizeOf(typeof(MONITORINFOEX));
            public RECT rcMonitor = new RECT();
            public RECT rcWork = new RECT();
            [MarshalAs(UnmanagedType.ByValArray, SizeConst = 32)]
            public char[] szDevice = new char[32];
            public int dwFlags;
        }
    }

    static Int32Rect _getOsInteropRect(Window w)
    {
        bool multimonSupported = OSInterop.GetSystemMetrics(OSInterop.SM_CMONITORS) != 0;
        if (!multimonSupported)
        {
            OSInterop.RECT rc = new OSInterop.RECT();
            OSInterop.SystemParametersInfo(48, 0, ref rc, 0);
            return new Int32Rect(rc.left, rc.top, rc.width, rc.height);
        }

        WindowInteropHelper helper = new WindowInteropHelper(w);
        IntPtr hmonitor = OSInterop.MonitorFromWindow(new HandleRef((object)null, helper.EnsureHandle()), 2);
        OSInterop.MONITORINFOEX info = new OSInterop.MONITORINFOEX();
        OSInterop.GetMonitorInfo(new HandleRef((object)null, hmonitor), info);
        return new Int32Rect(info.rcWork.left, info.rcWork.top, info.rcWork.width, info.rcWork.height);
    }

    public static Rect GetAbsoluteRect(this Window w)
    {
        if (w.WindowState != WindowState.Maximized)
            return new Rect(w.Left, w.Top, w.ActualWidth, w.ActualHeight);

        var r = _getOsInteropRect(w);
        return new Rect(r.X, r.Y, r.Width, r.Height);
    }

    public static Point GetAbsolutePosition(this Window w)
    {
        if (w.WindowState != WindowState.Maximized)
            return new Point(w.Left, w.Top);

        var r = _getOsInteropRect(w);
        return new Point(r.X, r.Y);
    }
}