Save and Restore WPF Window Size, Position, and/or State

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Introduction

A quick example of how you can save a window's size, position, and/or state, and restore to that size, position, and state the next time the app is launched.

Background

This started as part of a real world app where I wanted the user to be able to resize the window and not have the window return to the default size the next time the app was launched. Many of my users have two monitors, so I decided to let them choose which monitor to open the window on, but I also wanted to make sure it didn't open on their "second monitor" when they took their laptop home and had only one monitor.

Using the Code

The first thing I did was setup some user settings to hold the data I wanted to save.

Then, I created a UserPreferences class to handle loading and saving of the settings. The class consists of a property (with backing variable) for each of the settings, and a few methods for loading, saving, and manipulating the settings.

Here are the methods for loading and saving the settings. Notice that when I save the settings, I don't save if the window state is minimized. I don't want my app to start minimized.

private void Load()
{
    _windowTop = Properties.Settings.Default.WindowTop;
    _windowLeft = Properties.Settings.Default.WindowLeft;
    _windowHeight = Properties.Settings.Default.WindowHeight;
    _windowWidth = Properties.Settings.Default.WindowWidth;
    _windowState = Properties.Settings.Default.WindowState;
}

public void Save()
{
    if (_windowState != System.Windows.WindowState.Minimized)
    {
        Properties.Settings.Default.WindowTop = _windowTop;
        Properties.Settings.Default.WindowLeft = _windowLeft;
        Properties.Settings.Default.WindowHeight = _windowHeight;
        Properties.Settings.Default.WindowWidth = _windowWidth;
        Properties.Settings.Default.WindowState = _windowState;

        Properties.Settings.Default.Save();
    }
}

I then created a method to shrink the window down to fit in the current desktop, if needed.

public void SizeToFit()
{
    if (_windowHeight > System.Windows.SystemParameters.VirtualScreenHeight)
    {
        _windowHeight = System.Windows.SystemParameters.VirtualScreenHeight;
    }

    if (_windowWidth > System.Windows.SystemParameters.VirtualScreenWidth)
    {
        _windowWidth = System.Windows.SystemParameters.VirtualScreenWidth;
    }
}

And lastly, I created a method that moves the window onto the desktop if it is more than half out of view. This is really important if you are going to save the position, because we don't want to restore the window to a position off the user's desktop.

public void MoveIntoView()
{
    if (_windowTop + _windowHeight / 2 > 
         System.Windows.SystemParameters.VirtualScreenHeight)
    {
        _windowTop = 
          System.Windows.SystemParameters.VirtualScreenHeight - 
          _windowHeight;
    }

    if (_windowLeft + _windowWidth / 2 > 
             System.Windows.SystemParameters.VirtualScreenWidth)
    {
        _windowLeft = 
          System.Windows.SystemParameters.VirtualScreenWidth - 
          _windowWidth;
    }

    if (_windowTop < 0)
    {
        _windowTop = 0;
    } 
    
    if (_windowLeft < 0)
    {
        _windowLeft = 0;
    }
}

The constructor for the UserPreferences class calls Load(), SizeToFit(), and MoveIntoView().

public UserPreferences()
{
    //Load the settings
    Load();

    //Size it to fit the current screen
    SizeToFit();

    //Move the window at least partially into view
    MoveIntoView();
}

Then, in the window you want to resize, we just load the settings into the window in the constructor, and save the settings on Window_Closing.

public Window1()
{
    InitializeComponent();

    var userPrefs = new UserPreferences();

    this.Height = userPrefs.WindowHeight;
    this.Width = userPrefs.WindowWidth;
    this.Top = userPrefs.WindowTop;
    this.Left = userPrefs.WindowLeft;
    this.WindowState = userPrefs.WindowState;

}

private void Window_Closing(object sender, 
             System.ComponentModel.CancelEventArgs e)
{
    var userPrefs = new UserPreferences();

    userPrefs.WindowHeight = this.Height;
    userPrefs.WindowWidth = this.Width;
    userPrefs.WindowTop=this.Top ;
    userPrefs.WindowLeft = this.Left;
    userPrefs.WindowState = this.WindowState;
    
    userPrefs.Save();
}

Points of Interest

When I resized and repositioned my form, I didn't take into account the height of the Windows task bar, so if the user resizes the screen to a smaller screen, the bottom of my form may be hidden by the task bar.

History

• 1/7/09 - Initial post.
• 1/8/09 - Removed binding from window to UserPreferences to allow setting the window size at design time and to prevent binding from being removed if you resize the window using a designer.