Restoring Window Size/Position With Multiple Monitors

Question

Many posts around about restoring a WinForm position and size.

Examples:

• https://mcmap.net/q/332466/-save-and-restore-form-position-and-size
• www.codeproject.com/KB/dialog/restoreposition.aspx?fid=1249382&df=90&mpp=25&noise=3&sort=Position&view=Quick&select=2595746

But I have yet to find code to do this with multiple monitors.

That is, if I close my .NET Winform app with the window on monitor 2, I want it to save the windows size, location, and state to the application settings, so it could later restore to monitor 2 when I restart the app. It would be nice if, like in the codeproject example above, it includes some sanity checks, as in if the saved location is mostly off-screen it "fixes" it. Or if the saved location is on a monitor that is no longer there (e.g. my laptop is now by itself without my second monitor) then it correctly moves it to monitor 1.

Any thoughts?

My environment: C#, .NET 3.5 or below, VS2008

Pirn

Answer 1

The answer provided by VVS was a great help! I found two minor issues with it though, so I am reposting the bulk of his code with these revisions:

(1) The very first time the application runs, the form is opened in a Normal state but is sized such that it appears as just a title bar. I added a conditional in the constructor to fix this.

(2) If the application is closed while minimized or maximized the code in OnClosing fails to remember the dimensions of the window in its Normal state. (The 3 lines of code--which I have now commented out--seems reasonable but for some reason just does not work.) Fortunately I had previously solved this problem and have included that code in a new region at the end of the code to track window state as it happens rather than wait for closing.

---

With these two fixes in place, I have tested:

A. closing in normal state--restores to same size/position and state

B. closing in minimized state--restores to normal state with last normal size/position

C. closing in maximized state--restores to maximized state and remembers its last size/position when one later adjusts to normal state.

D. closing on monitor 2--restores to monitor 2.

E. closing on monitor 2 then disconnecting monitor 2--restores to same position on monitor 1

David: your code allowed me to achieve points D and E almost effortlessly--not only did you provide a solution for my question, you provided it in a complete program so I had it up and running almost within seconds of pasting it into Visual Studio. So a big thank you for that!

public partial class MainForm : Form
{
    bool windowInitialized;

    public MainForm()
    {
        InitializeComponent();

        // this is the default
        this.WindowState = FormWindowState.Normal;
        this.StartPosition = FormStartPosition.WindowsDefaultBounds;

        // check if the saved bounds are nonzero and visible on any screen
        if (Settings.Default.WindowPosition != Rectangle.Empty &&
            IsVisibleOnAnyScreen(Settings.Default.WindowPosition))
        {
            // first set the bounds
            this.StartPosition = FormStartPosition.Manual;
            this.DesktopBounds = Settings.Default.WindowPosition;

            // afterwards set the window state to the saved value (which could be Maximized)
            this.WindowState = Settings.Default.WindowState;
        }
        else
        {
            // this resets the upper left corner of the window to windows standards
            this.StartPosition = FormStartPosition.WindowsDefaultLocation;

            // we can still apply the saved size
            // msorens: added gatekeeper, otherwise first time appears as just a title bar!
            if (Settings.Default.WindowPosition != Rectangle.Empty)
            {
                this.Size = Settings.Default.WindowPosition.Size;
            }
        }
        windowInitialized = true;
    }

    private bool IsVisibleOnAnyScreen(Rectangle rect)
    {
        foreach (Screen screen in Screen.AllScreens)
        {
            if (screen.WorkingArea.IntersectsWith(rect))
            {
                return true;
            }
        }

        return false;
    }

    protected override void OnClosed(EventArgs e)
    {
        base.OnClosed(e);

        // only save the WindowState if Normal or Maximized
        switch (this.WindowState)
        {
            case FormWindowState.Normal:
            case FormWindowState.Maximized:
                Settings.Default.WindowState = this.WindowState;
                break;

            default:
                Settings.Default.WindowState = FormWindowState.Normal;
                break;
        }

        # region msorens: this code does *not* handle minimized/maximized window.

        // reset window state to normal to get the correct bounds
        // also make the form invisible to prevent distracting the user
        //this.Visible = false;
        //this.WindowState = FormWindowState.Normal;
        //Settings.Default.WindowPosition = this.DesktopBounds;

        # endregion

        Settings.Default.Save();
    }

    # region window size/position
    // msorens: Added region to handle closing when window is minimized or maximized.

    protected override void OnResize(EventArgs e)
    {
        base.OnResize(e);
        TrackWindowState();
    }

    protected override void OnMove(EventArgs e)
    {
        base.OnMove(e);
        TrackWindowState();
    }

    // On a move or resize in Normal state, record the new values as they occur.
    // This solves the problem of closing the app when minimized or maximized.
    private void TrackWindowState()
    {
        // Don't record the window setup, otherwise we lose the persistent values!
        if (!windowInitialized) { return; }

        if (WindowState == FormWindowState.Normal)
        {
            Settings.Default.WindowPosition = this.DesktopBounds;
        }
    }

    # endregion window size/position
}

Pirn

For those interested in actually using this solution, I have taken the final step of converting the example into a library with a documented API (cleancode.sourceforge.net/api/csharp/…). With the library, you need only a couple lines to load/save settings, and a couple one-line event handlers--a total of 7 lines of code for everything! Download area is at cleancode.sourceforge.net/wwwdoc/download.html. – Pirn

Perhaps the problem with my code is that I shouldn't make the window invisible before changing the state. Perhaps I just should test it instead of guessing :) – Melonie

I found it worked without a stack overflow when I removed the base.OnMove() and base.OnResize() lines. Otherwise, great solution. – Orozco

You should use Form.RestoreBounds to get the location and size of the form when the WindowState is not Normal. Then you don't need TrackWindowState(). See also Cheeso's answer below. – Kleeman

What is the purpose of the TrackWindowState on resize and moving? Does this not add extra process that could be just done when closing? – Reavis

@MichaelSorens the link to the library code is now broken, could you provide the code as I am very interested to see your final version. Thanks for your time... – Aindrea

@Killercam: Yes, I did change the API pages and broke the link. Here is the corrected link: cleancode.sourceforge.net/api/csharp/html/…. The download link is still correct as given above, though, so you can grab the code anytime. – Pirn

Answer 2

Try this code. Points of interest:

• Checks if the window is (partially) visible on any screen's working area. E.g. dragging it behind the task bar or moving it completely offscreen resets the position to windows default.
• Saves the correct bounds even if the Form is minimized or maximized (common error)
• Saves the WindowState correctly. Saving FormWindowState.Minimized is disabled by design.

The bounds and state are stored in the appsettings with their corresponding type so there's no need to do any string parsing. Let the framework do its serialization magic.

public partial class MainForm : Form
{
    public MainForm()
    {
        InitializeComponent();

        // this is the default
        this.WindowState = FormWindowState.Normal;
        this.StartPosition = FormStartPosition.WindowsDefaultBounds;

        // check if the saved bounds are nonzero and visible on any screen
        if (Settings.Default.WindowPosition != Rectangle.Empty &&
            IsVisibleOnAnyScreen(Settings.Default.WindowPosition))
        {
            // first set the bounds
            this.StartPosition = FormStartPosition.Manual;
            this.DesktopBounds = Settings.Default.WindowPosition;

            // afterwards set the window state to the saved value (which could be Maximized)
            this.WindowState = Settings.Default.WindowState;
        }
        else
        {
            // this resets the upper left corner of the window to windows standards
            this.StartPosition = FormStartPosition.WindowsDefaultLocation;

            // we can still apply the saved size
            this.Size = Settings.Default.WindowPosition.Size;
        }
    }

    private bool IsVisibleOnAnyScreen(Rectangle rect)
    {
        foreach (Screen screen in Screen.AllScreens)
        {
            if (screen.WorkingArea.IntersectsWith(rect))
            {
                return true;
            }
        }

        return false;
    }

    protected override void OnClosed(EventArgs e)
    {
        base.OnClosed(e);

        // only save the WindowState if Normal or Maximized
        switch (this.WindowState)
        {
            case FormWindowState.Normal:
            case FormWindowState.Maximized:
                Settings.Default.WindowState = this.WindowState;
                break;

            default:
                Settings.Default.WindowState = FormWindowState.Normal;
                break;
        }

        // reset window state to normal to get the correct bounds
        // also make the form invisible to prevent distracting the user
        this.Visible = false;
        this.WindowState = FormWindowState.Normal;

        Settings.Default.WindowPosition = this.DesktopBounds;
        Settings.Default.Save();
    }
}

The settings file for reference:

<?xml version='1.0' encoding='utf-8'?>
<SettingsFile xmlns="http://schemas.microsoft.com/VisualStudio/2004/01/settings" CurrentProfile="(Default)" GeneratedClassNamespace="ScreenTest" GeneratedClassName="Settings">
    <Profiles />
    <Settings>
        <Setting Name="WindowPosition" Type="System.Drawing.Rectangle" Scope="User">
            <Value Profile="(Default)">0, 0, 0, 0</Value>
        </Setting>
        <Setting Name="WindowState" Type="System.Windows.Forms.FormWindowState" Scope="User">
            <Value Profile="(Default)">Normal</Value>
        </Setting>
    </Settings>
</SettingsFile>

Melonie

What's that Settings type you use? – Onagraceous

@ColonelPanic I used the default application settings class. For more info check here: learn.microsoft.com/en-us/dotnet/framework/winforms/advanced/… – Melonie

Works well, but with .NET 4.7 I had to set the form invisible after copying DesktopBounds to the Settings or else it remained at the maximized size.. – Ambidexterity

Answer 3

Most of the other solutions here rely on manually figuring out the current positioning of each monitor. The edge cases are extremely difficult to figure out, and very few apps can get it right rolling their own.

The SetWindowPlacement function within Windows itself correctly handles all of the edge cases - if the window would be positioned off of a visible screen, it adjusts it accordingly.

The best example I've seen in C# is on David Rickard's blog. Not only does it show how to use SetWindowPlacement, it also shows how to serialize the entire result. http://blogs.msdn.com/b/davidrickard/archive/2010/03/09/saving-window-size-and-location-in-wpf-and-winforms.aspx

Daly

Answer 4

This is the perfect one I think based on your answers and comments.

---

This solution is to save/restore form size and position with multi monitors + multi document, multi form or multi main form support. It is not MDI form but Microsoft Word like multi document with different main form instance.

Thanks to VVS, msorens and Ian Goldby. I merge the solution from VVS, msorens and MSDN Application.Run Method (ApplicationContext) example to make the multi MainForm but not MDI.

This fix of includes the comment from Ian Goldby which uses Form.RestoreBounds to eliminate OnResize(), OnMove() and TrackWindowState().

I also fix to remember the Monitor when the Form move to the other Monitor and getting maximized before exit because I not tracking the OnResize, OnMove. By this fix, this solution support Windows 7 Snap feature which you can drag the titlebar or Win+Arrow key to snap Form window into any monitor edge or make it maximized/normal as well as minimized.

This solution implemented in Program but not in the main Form to support multi main Form. However you can use for single main Form also.

using System;
using System.Collections.Generic;
using System.Windows.Forms;
using SimpleTestForm.Properties;
using System.Drawing;

namespace SimpleTestForm
{
    static class Program
    {
        static MultiMainFormAppContext appContext;

        /// <summary>
        /// The main entry point for the application.
        /// </summary>
        [STAThread]
        static void Main()
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);

            appContext = new MultiMainFormAppContext();
            Application.Run(appContext);
        }

        /// <summary>
        /// Create a new MainForm and restore the form size and position if necessary. This method can be called like from Menu File > New click event.
        /// </summary>
        /// <returns></returns>
        public static MainForm createNewMainForm()
        {
            return appContext.createNewMainForm();
        }

        /// <summary>
        /// Get the current active MainForm event if a dialog is opened. Useful to create Dictionary (MainForm, T) to store Form/document dependent field. Please set the Owner of child form to prevent null reference exception.
        /// </summary>
        /// <returns></returns>
        public static MainForm GetCurrentMainFormInstance()
        {
            Form mainForm = Form.ActiveForm;
            while (!(mainForm is MainForm) && mainForm.Owner != null)
                mainForm = mainForm.Owner;
            return mainForm as MainForm;
        }
    }

    class MultiMainFormAppContext : ApplicationContext
    {
        List<MainForm> mainForms = new List<MainForm>();
        Point newRestoredLocation = Point.Empty;

        internal MultiMainFormAppContext()
        {
            createNewMainForm();
        }

        internal MainForm createNewMainForm()
        {
            MainForm mainForm = new MainForm();
            mainForm.FormClosed += new FormClosedEventHandler(mainForm_FormClosed);
            mainForm.LocationChanged += new EventHandler(mainForm_LocationChanged);
            RestoreFormSizeNPosition(mainForm);
            PreventSameLocation(mainForm);
            mainForms.Add(mainForm);
            mainForm.Show();
            return mainForm;
        }

        private void PreventSameLocation(MainForm mainForm)
        {
            const int distance = 20;
            foreach (MainForm otherMainForm in mainForms)
            {
                if (Math.Abs(otherMainForm.Location.X - mainForm.Location.X) < distance &&
                    Math.Abs(otherMainForm.Location.Y - mainForm.Location.Y) < distance)
                    mainForm.Location = new Point(mainForm.Location.X + distance, mainForm.Location.Y + distance);
            }
        }

        /// <summary>
        /// Restore the form size and position with multi monitor support.
        /// </summary>
        private void RestoreFormSizeNPosition(MainForm mainForm)
        {
            // this is the default
            mainForm.WindowState = FormWindowState.Normal;
            mainForm.StartPosition = FormStartPosition.WindowsDefaultBounds;

            // check if the saved bounds are nonzero and visible on any screen
            if (Settings.Default.WindowPosition != Rectangle.Empty &&
                IsVisibleOnAnyScreen(Settings.Default.WindowPosition))
            {
                // first set the bounds
                mainForm.StartPosition = FormStartPosition.Manual;
                mainForm.DesktopBounds = Settings.Default.WindowPosition;

                // afterwards set the window state to the saved value (which could be Maximized)
                mainForm.WindowState = Settings.Default.WindowState;
            }
            else
            {
                // this resets the upper left corner of the window to windows standards
                mainForm.StartPosition = FormStartPosition.WindowsDefaultLocation;

                // we can still apply the saved size if not empty
                if (Settings.Default.WindowPosition != Rectangle.Empty)
                {
                    mainForm.Size = Settings.Default.WindowPosition.Size;
                }
            }
        }

        private void SaveFormSizeNPosition(MainForm mainForm)
        {
            // only save the WindowState as Normal or Maximized
            Settings.Default.WindowState = FormWindowState.Normal;
            if (mainForm.WindowState == FormWindowState.Normal || mainForm.WindowState == FormWindowState.Maximized)
                Settings.Default.WindowState = mainForm.WindowState;

            if (mainForm.WindowState == FormWindowState.Normal)
            {
                Settings.Default.WindowPosition = mainForm.DesktopBounds;
            }
            else
            {
                if (newRestoredLocation == Point.Empty)
                    Settings.Default.WindowPosition = mainForm.RestoreBounds;
                else
                    Settings.Default.WindowPosition = new Rectangle(newRestoredLocation, mainForm.RestoreBounds.Size);
            }

            Settings.Default.Save();
        }

        private bool IsVisibleOnAnyScreen(Rectangle rect)
        {
            foreach (Screen screen in Screen.AllScreens)
            {
                if (screen.WorkingArea.IntersectsWith(rect))
                    return true;
            }
            return false;
        }

        void mainForm_LocationChanged(object sender, EventArgs e)
        {
            MainForm mainForm = sender as MainForm;
            if (mainForm.WindowState == FormWindowState.Maximized)
            {
                // get the center location of the form incase like RibbonForm will be bigger and maximized Location wll be negative value that Screen.FromPoint(mainForm.Location) will going to the other monitor resides on the left or top of primary monitor.
                // Another thing, you might consider the form is in the monitor even if the location (top left corner) is on another monitor because majority area is on the monitor, so center point is the best way.
                Point centerFormMaximized = new Point (mainForm.DesktopBounds.Left + mainForm.DesktopBounds.Width/2, mainForm.DesktopBounds.Top + mainForm.DesktopBounds.Height/2);
                Point centerFormRestored = new Point(mainForm.RestoreBounds.Left + mainForm.RestoreBounds.Width / 2, mainForm.RestoreBounds.Top + mainForm.RestoreBounds.Height / 2);
                Screen screenMaximized = Screen.FromPoint(centerFormMaximized);
                Screen screenRestored = Screen.FromPoint(centerFormRestored);
                // we need to change the Location of mainForm.RestoreBounds to the new screen where the form currently maximized.
                // RestoreBounds does not update the Location if you change the screen but never restore to FormWindowState.Normal
                if (screenMaximized.DeviceName != screenRestored.DeviceName)
                {
                    newRestoredLocation = mainForm.RestoreBounds.Location;
                    int screenOffsetX = screenMaximized.Bounds.Location.X - screenRestored.Bounds.Location.X;
                    int screenOffsetY = screenMaximized.Bounds.Location.Y - screenRestored.Bounds.Location.Y;
                    newRestoredLocation.Offset(screenOffsetX, screenOffsetY);
                    return;
                }
            }
            newRestoredLocation = Point.Empty;
        }

        void mainForm_FormClosed(object sender, FormClosedEventArgs e)
        {
            MainForm mainForm = sender as MainForm;
            SaveFormSizeNPosition(mainForm);
            mainForm.FormClosed -= new FormClosedEventHandler(mainForm_FormClosed);
            mainForm.LocationChanged -= new EventHandler(mainForm_LocationChanged);
            mainForm.Dispose();
            mainForms.Remove(mainForm);
            if (mainForms.Count == 0) ExitThread();
        }
    }
}

Edit: PreventSameLocation method added to make sure the 2nd form opened not exactly on top of the 1st form and user will notice the newly opened form.

Feigin

Answer 5

If you have multiple monitors, I believe the screen UI dimensions are simply larger. So the normal "1 monitor" approach of storing and restoring the location will just work. I haven't tried this because I am away from my second monitor but it shouldn't be hard to test. The way you asked the Question is seems like you haven't tested it.

Your second requirement will mean you will have to check the max sceen dimensions when restoring the app, and then reposition as necessary. To do this latter bit, I use this code:

    private System.Drawing.Rectangle ConstrainToScreen(System.Drawing.Rectangle bounds)
    {
        Screen screen = Screen.FromRectangle(bounds);
        System.Drawing.Rectangle workingArea = screen.WorkingArea;
        int width = Math.Min(bounds.Width, workingArea.Width);
        int height = Math.Min(bounds.Height, workingArea.Height);
        // mmm....minimax            
        int left = Math.Min(workingArea.Right - width, Math.Max(bounds.Left, workingArea.Left));
        int top = Math.Min(workingArea.Bottom - height, Math.Max(bounds.Top, workingArea.Top));
        return new System.Drawing.Rectangle(left, top, width, height);
    }

I call this method when restoring the form. I store the screen geometry in the registry on form close, and then read the geometry on form open. I get the bounds, but then constrain the restored bounds to the actual current screen, using the method above.

Save on close:

      // store the size of the form
      int w = 0, h = 0, left = 0, top = 0;
      if (this.Bounds.Width < this.MinimumSize.Width || this.Bounds.Height < this.MinimumSize.Height)
      {
          // The form is currently minimized.  
          // RestoreBounds is the size of the window prior to last minimize action.
          w = this.RestoreBounds.Width;
          h = this.RestoreBounds.Height;
          left = this.RestoreBounds.Location.X;
          top = this.RestoreBounds.Location.Y;
      }
      else
      {
          w = this.Bounds.Width;
          h = this.Bounds.Height;
          left = this.Location.X;
          top = this.Location.Y;
      }
      AppCuKey.SetValue(_rvn_Geometry,
        String.Format("{0},{1},{2},{3},{4}",
              left, top, w, h, (int)this.WindowState));

Restore on form open:

    // restore the geometry of the form
    string s = (string)AppCuKey.GetValue(_rvn_Geometry);
    if (!String.IsNullOrEmpty(s))
    {
        int[] p = Array.ConvertAll<string, int>(s.Split(','),
                         new Converter<string, int>((t) => { return Int32.Parse(t); }));
        if (p != null && p.Length == 5)
            this.Bounds = ConstrainToScreen(new System.Drawing.Rectangle(p[0], p[1], p[2], p[3]));
    }

Actualize

Answer 6

This is an old question, but here is a VB version based on the previous answers.

One problem with the answers suggested by VVS and Michael Sorens is that a saved position that only shows a couple of pixels on a screen counts as visible. This solution requires at least 50x50 pixels in intersection before restoring the previous location.

Settings:

<Settings>
  <Setting Name="WindowState" Type="System.Windows.Forms.FormWindowState" Scope="User">
    <Value Profile="(Default)">Normal</Value>
  </Setting>
  <Setting Name="WindowBounds" Type="System.Drawing.Rectangle" Scope="User">
    <Value Profile="(Default)">10, 10, 800, 600</Value>
  </Setting>
</Settings>

Form:

Partial Public Class MainForm

    Private loadingComplete As Boolean = False

    Public Sub New()

        InitializeComponent()
        RestoreWindowLocation()

    End Sub

    Private Sub MainForm_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load

        loadingComplete = True

    End Sub

    Private Sub MainForm_Resize(sender As System.Object, e As System.EventArgs) Handles MyBase.Resize

         TrackWindowLocation()

     End Sub

     Private Sub MainForm_Move(sender As System.Object, e As System.EventArgs) Handles MyBase.Move

         TrackWindowLocation()

     End Sub

    Private Sub MainForm_FormClosing(sender As System.Object, e As System.Windows.Forms.FormClosingEventArgs) Handles MyBase.FormClosing

        SaveWindowLocation()

     End Sub


    Private Sub RestoreWindowLocation()

        If IsRectangleVisible(My.Settings.WindowBounds) Then
            Me.StartPosition = FormStartPosition.Manual
            Me.DesktopBounds = My.Settings.WindowBounds
        End If

        If Not My.Settings.WindowState = FormWindowState.Minimized Then
            Me.WindowState = My.Settings.WindowState
        End If

    End Sub

    Private Sub TrackWindowLocation()

        If loadingComplete Then
            If Me.WindowState = FormWindowState.Normal Then
                My.Settings.WindowBounds = Me.DesktopBounds
                My.Settings.WindowState = Me.WindowState
            End If
        End If

    End Sub

    Private Sub SaveWindowLocation()

        If Not Me.WindowState = FormWindowState.Minimized Then
            My.Settings.WindowState = Me.WindowState
        End If

        If Me.WindowState = FormWindowState.Normal Then
            My.Settings.WindowBounds = Me.DesktopBounds
        End If

        My.Settings.Save()

    End Sub

    Private Function IsRectangleVisible(Rectangle As Rectangle) As Boolean

        For Each screen As Screen In screen.AllScreens
            Dim r As Rectangle = Rectangle.Intersect(Rectangle, screen.WorkingArea)
            If Not r.IsEmpty Then
                If r.Width > 50 And r.Height > 50 Then Return True
            End If
        Next

        Return False

    End Function

End Class

Potiche