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Keep track of screen change and screen resolution change in Windows Form Application to change form size

I want to change form size depending on Screen and it's resolution.
What I want is a correct event to track these screen changes as well as screen resolution changes at runtime.
In other words,
If user is using two screens and move application to another screen, that should be tracked and change size accordingly, i.e. reduce size if new screen's resolution is low or increase size if resolution is larger.
Also track screen resolution change on the same screen, and make changes to size accordingly.
I know how to change Form size, get current screen and it's resolution, just need these events to keep track of these changes.

Going over this answer I've decided to improve it and add further information to form a more complete solution.
The Challenge
Tracking which screen a Form is currently being rendered on. This can change if a user drags the form to another monitor or unplugs a monitor. The resolution can change if a user manually drags a window to a different display or changes the resolution directly.
Firstly, tracking form location. We need to hook into a Move event for the form context, fortunately the .Net framework provides such an event, and it is named Control.Move Event.
Secondly, we will need to hook into a screen resolution changed event, we can do this with the SystemEvents.DisplaySettingsChanged event.
And putting it together, I got this:
struct Resolution
{
public int Width;
public int Height;
}
int previous = -1;
int current = -1;
private bool CheckScreenChanged()
{
bool changed = false;
current = GetScreenIndex();
if (current != -1 && previous != -1 && current != previous) // form changed screen.
{
changed = true;
}
previous = current;
return changed;
}
private int GetScreenIndex()
{
return Array.IndexOf(Screen.AllScreens, Screen.FromControl(this));
}
private Resolution GetCurrentResolution()
{
Screen screen = Screen.FromControl(this);
Resolution res = new Resolution();
res.Width = screen.Bounds.Width;
res.Height = screen.Bounds.Height;
return res;
}
private void SetResolutionLabel()
{
Resolution res = GetCurrentResolution();
label2.Text = String.Format("Width: {0}, Height: {1}", res.Width, res.Height);
}
private void ScreenChanged()
{
label1.Text = "Screen " + current.ToString();
}
private void Form_Moved(object sender, System.EventArgs e)
{
bool changed = CheckScreenChanged();
if (changed == true)
{
ScreenChanged();
SetResolutionLabel();
}
}
public void SystemEvents_DisplaySettingsChanged(object sender, EventArgs e)
{
SetResolutionLabel();
}
public void Initialize()
{
this.Move += Form_Moved;
SystemEvents.DisplaySettingsChanged += new
EventHandler(SystemEvents_DisplaySettingsChanged);
previous = GetScreenIndex();
current = GetScreenIndex();
ScreenChanged();
SetResolutionLabel();
}
The code above is tested on a simple form with two labels called label1 and label2, which are updated when the screen the form is on changes or the resolution changes.
An image of this in action on my primary screen/display
And on my secondary screen/display when the form has been dragged to it:

Move Form onto specified Screen

I am trying to figure out how to move specified System.Windows.Forms.Form onto another than primary screen. I have ComboBox with list of available screens where user selects whichever screen he likes and my application is supposed to move one of its windows onto that screen.
I have only one screen on my laptop and no external monitor, so ComboBox on my computer offers only one option. I think minimalising desired window, moving it's left corner in the center of selected screen's Bounds and maximilising would do the job, right? I just can't test it. Is this a good way to go?
Thanks in advance!

Here's what I did, as a simple test...
I added a simple wrapper class so that I could change what happens on the ToString call (I only wanted to see the name listed in the combo box)
private class ScreenObj
{
public Screen screen = null;
public ScreenObj(Screen scr)
{
screen = scr;
}
public override string ToString()
{
return screen.DeviceName;
}
}
In the form load event I added this:
foreach(Screen screen in Screen.AllScreens)
{
cboScreens.Items.Add(new ScreenObj(screen));
}
And for the selected index change event of the combo box I had this:
private void cboScreens_SelectedIndexChanged(object sender, EventArgs e)
{
object o = cboScreens.SelectedItem;
if(null == o)
return;
ScreenObj scrObj = o as ScreenObj;
if(null == scrObj)
return;
Point p = new Point();
p.X = scrObj.screen.WorkingArea.Left;
p.Y = scrObj.screen.WorkingArea.Top;
this.Location = p;
}
It moved the form to the upper left hand corner of each of my screens.

How do I ensure a form displays on the "additional" monitor in a dual monitor scenario? [duplicate]

This question already has answers here:
Showing a Windows form on a secondary monitor?
(9 answers)
Closed 9 years ago.
I have an application in which there is a form which I want to show on second screen.
Mean If application is running on screen A and when I click on menu to show Form it should display on Screen B
and same with if application is running on screen B and when I click on menu to show Form it should display on Screen A.

You need to use the Screen class to find a screen that the original form is not on, then set the second form's Location property based on that screen's Bounds.
For example:
var myScreen = Screen.FromControl(originalForm);
var otherScreen = Screen.AllScreens.FirstOrDefault(s => !s.Equals(myScreen))
?? myScreen;
otherForm.Left = otherScreen.WorkingArea.Left + 120;
otherForm.Top = otherScreen.WorkingArea.Top + 120;
This will work for any number of screens.
Note that it is possible that the video card is configured so that Windows sees one large screen instead of two smaller ones, in which case this becomes much more difficult.

Below is a function allowing you to display a form on any monitor. For your current scenario you can call this showOnMonitor(1);.
Essentially you have to get screen information from Screen.AllScreens and then get the dimensions of each, then place your form where you need it
function void showOnMonitor(int showOnMonitor)
{
Screen[] sc;
sc = Screen.AllScreens;
Form2 f = new Form2();
f.FormBorderStyle = FormBorderStyle.None;
f.Left = sc[showOnMonitor].Bounds.Left;
f.Top = sc[showOnMonitor].Bounds.Top;
f.StartPosition = FormStartPosition.Manual;
f.Show();
}
Note don't forget to do validation to ensure you actually have two screens etc else an exception will be thrown for accessing sc[showOnMonitor]

On the OnLoad method change the Location of the window.
protected void Form1_OnLoad(...) {
showOnMonitor(1);
}
private void showOnMonitor(int showOnMonitor)
{
Screen[] sc;
sc = Screen.AllScreens;
if (showOnMonitor >= sc.Length) {
showOnMonitor = 0;
}
this.StartPosition = FormStartPosition.Manual;
this.Location = new Point(sc[showOnMonitor].Bounds.Left, sc[showOnMonitor].Bounds.Top);
// If you intend the form to be maximized, change it to normal then maximized.
this.WindowState = FormWindowState.Normal;
this.WindowState = FormWindowState.Maximized;
}

I used this for an XNA 4 Dual Screen Application (Full Screen XNA Game Window + WinForm)
In the Form_Load() method, place the following code:
var primaryDisplay = Screen.AllScreens.ElementAtOrDefault(0);
var extendedDisplay = Screen.AllScreens.FirstOrDefault(s => s != primaryDisplay) ?? primaryDisplay;
this.Left = extendedDisplay.WorkingArea.Left + (extendedDisplay.Bounds.Size.Width / 2) - (this.Size.Width / 2);
this.Top = extendedDisplay.WorkingArea.Top + (extendedDisplay.Bounds.Size.Height / 2) - (this.Size.Height / 2);

How to record window position in Windows Forms application settings

It seems like a standard requirement: next time the user launches the application, open the window in the same position and state as it was before. Here's my wish list:
Window position same as it was
Unless the screen has resized and the old position is now off screen.
Splitters should retain their position
Tab containers should retain their selection
Some dropdowns should retain their selection
Window state (maximize, minimize, normal) is the same as it was.
Maybe you should never start minimized, I haven't decided.
I'll add my current solutions as an answer along with the limitations.

My other option is to write more custom code around the application settings and execute it on formLoad and formClosed. This doesn't use data binding.
Drawbacks:
More code to write.
Very fiddly. The order you set the properties on formLoad is confusing. For example, you have to make sure you've set the window size before you set the splitter distance.
Right now, this is my preferred solution, but it seems like too much work. To reduce the work, I created a WindowSettings class that serializes the window location, size, state, and any splitter positions to a single application setting. Then I can just create a setting of that type for each form in my application, save on close, and restore on load.
I posted the source code, including the WindowSettings class and some forms that use it. Instructions on adding it to a project are included in the WindowSettings.cs file. The trickiest part was figuring out how to add an application setting with a custom type. You choose Browse... from the type dropdown, and then manually enter the namespace and class name. Types from your project don't show up in the list.
Update: I added some static methods to simplify the boilerplate code that you add to each form. Once you've followed the instructions for adding the WindowSettings class to your project and creating an application setting, here's an example of the code that has to be added to each form whose position you want to record and restore.
private void MyForm_FormClosing(object sender, FormClosingEventArgs e)
{
Settings.Default.CustomWindowSettings = WindowSettings.Record(
Settings.Default.CustomWindowSettings,
this,
splitContainer1);
}
private void MyForm_Load(object sender, EventArgs e)
{
WindowSettings.Restore(
Settings.Default.CustomWindowSettings,
this,
splitContainer1);
}

The sample below shows how I do it
SavePreferences is called when closing the form and saves the form's size, and a flag indicating if it's maximized (in this version I don't save if it's minimized - it will come back up restored or maximized next time).
LoadPreferences is called from OnLoad.
First save the design-time WindowState and set it to Normal. You can only successfully set the form size if it's WindowState is Normal.
Next restore the Size from your persisted settings.
Now make sure the form fits on your screen (call to FitToScreen). The screen resolution may have changed since you last ran the application.
Finally set the WindowState back to Maximized (if persisted as such), or to the design-time value saved earlier.
This could obviously be adapted to persist the start position and whether the form was minimized when closed - I didn't need to do that. Other settings for controls on your form such as splitter position and tab container are straightforward.
private void FitToScreen()
{
if (this.Width > Screen.PrimaryScreen.WorkingArea.Width)
{
this.Width = Screen.PrimaryScreen.WorkingArea.Width;
}
if (this.Height > Screen.PrimaryScreen.WorkingArea.Height)
{
this.Height = Screen.PrimaryScreen.WorkingArea.Height;
}
}
private void LoadPreferences()
{
// Called from Form.OnLoad
// Remember the initial window state and set it to Normal before sizing the form
FormWindowState initialWindowState = this.WindowState;
this.WindowState = FormWindowState.Normal;
this.Size = UserPreferencesManager.LoadSetting("_Size", this.Size);
_currentFormSize = Size;
// Fit to the current screen size in case the screen resolution
// has changed since the size was last persisted.
FitToScreen();
bool isMaximized = UserPreferencesManager.LoadSetting("_Max", initialWindowState == FormWindowState.Maximized);
WindowState = isMaximized ? FormWindowState.Maximized : FormWindowState.Normal;
}
private void SavePreferences()
{
// Called from Form.OnClosed
UserPreferencesManager.SaveSetting("_Size", _currentFormSize);
UserPreferencesManager.SaveSetting("_Max", this.WindowState == FormWindowState.Maximized);
... save other settings
}
x

The simplest solution I've found is to use data binding with the application settings. I bind the location and clientSize properties on the window along with the splitterDistance on the splitter.
Drawbacks:
If you close the window while minimized, it opens hidden the next time. It's really hard to get the window back.
If you close the window while maximized, it opens filling the whole screen, but not maximized (minor issue).
Resizing the window using the top-right corner or the bottom-left corner is just ugly. I guess the two databound properties are fighting each other.
If you'd like to experiment with the strange behaviour, I posted a sample solution using this technique.

I make a Setting for each value I want to save, and use code like this:
private void MainForm_Load(object sender, EventArgs e) {
RestoreState();
}
private void MainForm_FormClosing(object sender, FormClosingEventArgs e) {
SaveState();
}
private void SaveState() {
if (WindowState == FormWindowState.Normal) {
Properties.Settings.Default.MainFormLocation = Location;
Properties.Settings.Default.MainFormSize = Size;
} else {
Properties.Settings.Default.MainFormLocation = RestoreBounds.Location;
Properties.Settings.Default.MainFormSize = RestoreBounds.Size;
}
Properties.Settings.Default.MainFormState = WindowState;
Properties.Settings.Default.SplitterDistance = splitContainer1.SplitterDistance;
Properties.Settings.Default.Save();
}
private void RestoreState() {
if (Properties.Settings.Default.MainFormSize == new Size(0, 0)) {
return; // state has never been saved
}
StartPosition = FormStartPosition.Manual;
Location = Properties.Settings.Default.MainFormLocation;
Size = Properties.Settings.Default.MainFormSize;
// I don't like an app to be restored minimized, even if I closed it that way
WindowState = Properties.Settings.Default.MainFormState ==
FormWindowState.Minimized ? FormWindowState.Normal : Properties.Settings.Default.MainFormState;
splitContainer1.SplitterDistance = Properties.Settings.Default.SplitterDistance;
}
Keep in mind that recompiling wipes the config file where the settings are stored, so test it without making code changes in between a save and a restore.

Based on the accepted answer by Don Kirkby and the WindowSettings class he wrote, you could derive a CustomForm from the standard one to reduce the amount of identical code written for each and every form, maybe like this:
using System;
using System.Configuration;
using System.Reflection;
using System.Windows.Forms;
namespace CustomForm
{
public class MyCustomForm : Form
{
private ApplicationSettingsBase _appSettings = null;
private string _settingName = "";
public Form() : base() { }
public Form(ApplicationSettingsBase settings, string settingName)
: base()
{
_appSettings = settings;
_settingName = settingName;
this.Load += new EventHandler(Form_Load);
this.FormClosing += new FormClosingEventHandler(Form_FormClosing);
}
private void Form_Load(object sender, EventArgs e)
{
if (_appSettings == null) return;
PropertyInfo settingProperty = _appSettings.GetType().GetProperty(_settingName);
if (settingProperty == null) return;
WindowSettings previousSettings = settingProperty.GetValue(_appSettings, null) as WindowSettings;
if (previousSettings == null) return;
previousSettings.Restore(this);
}
private void Form_FormClosing(object sender, FormClosingEventArgs e)
{
if (_appSettings == null) return;
PropertyInfo settingProperty = _appSettings.GetType().GetProperty(_settingName);
if (settingProperty == null) return;
WindowSettings previousSettings = settingProperty.GetValue(_appSettings, null) as WindowSettings;
if (previousSettings == null)
previousSettings = new WindowSettings();
previousSettings.Record(this);
settingProperty.SetValue(_appSettings, previousSettings, null);
_appSettings.Save();
}
}
}
To use this, pass your application settings class and setting name in the constructor:
CustomForm.MyCustomForm f = new CustomForm.MyCustomForm(Properties.Settings.Default, "formSettings");
This uses Reflection to get/set the previous settings from/to the settings class. It may not be optimal to put the Save call into the Form_Closing routine, one could remove that and save the settings file whenever the main app exits.
To use it as a regular form, just use the parameterless constructor.

You can use the application settings to set which control properties will be persisted, in the Form_closed event you have to use the save method on the application settings to write these to disk:
Properties.Settings.Default.Save();

Here is an example of a few I use myself. It only takes into consideration the primary monitor, so it might be better to handle it differently if used on multiple monitors.
Size size;
int x;
int y;
if (WindowState.Equals(FormWindowState.Normal))
{
size = Size;
if (Location.X + size.Width > Screen.PrimaryScreen.Bounds.Width)
x = Screen.PrimaryScreen.Bounds.Width - size.Width;
else
x = Location.X;
if (Location.Y + Size.Height > Screen.PrimaryScreen.Bounds.Height)
y = Screen.PrimaryScreen.Bounds.Height - size.Height;
else
y = Location.Y;
}
else
{
size = RestoreBounds.Size;
x = (Screen.PrimaryScreen.Bounds.Width - size.Width)/2;
y = (Screen.PrimaryScreen.Bounds.Height - size.Height)/2;
}
Properties.Settings.Position.AsPoint = new Point(x, y); // Property setting is type of Point
Properties.Settings.Size.AsSize = size; // Property setting is type of Size
Properties.Settings.SplitterDistance.Value = splitContainer1.SplitterDistance; // Property setting is type of int
Properties.Settings.IsMaximized = WindowState == FormWindowState.Maximized; // Property setting is type of bool
Properties.Settings.DropDownSelection = DropDown1.SelectedValue;
Properties.Settings.Save();

A hack you can use Settings to store that information. All you have to do is bind the desired property (ex. form.Size and form.Location) to a specific setting and it get saved and updated automatically.

Why can't you bind the Size of a windows form to ApplicationSettings?

Update: Solved, with code
I got it working, see my answer below for the code...
Original Post
As Tundey pointed out in his answer to my last question, you can bind nearly everything about a windows forms control to ApplicationSettings pretty effortlessly. So is there really no way to do this with form Size? This tutorial says you need to handle Size explicitly so you can save RestoreBounds instead of size if the window is maximized or minimized. However, I hoped I could just use a property like:
public Size RestoreSize
{
get
{
if (this.WindowState == FormWindowState.Normal)
{
return this.Size;
}
else
{
return this.RestoreBounds.Size;
}
}
set
{
...
}
}
But I can't see a way to bind this in the designer (Size is notably missing from the PropertyBinding list).

I finally came up with a Form subclass that solves this, once and for all. To use it:
Inherit from RestorableForm instead of Form.
Add a binding in (ApplicationSettings) -> (PropertyBinding) to WindowRestoreState.
Call Properties.Settings.Default.Save() when the window is about to close.
Now window position and state will be remembered between sessions. Following the suggestions from other posters below, I included a function ConstrainToScreen that makes sure the window fits nicely on the available displays when restoring itself.
Code
// Consider this code public domain. If you want, you can even tell
// your boss, attractive women, or the other guy in your cube that
// you wrote it. Enjoy!
using System;
using System.Windows.Forms;
using System.ComponentModel;
using System.Drawing;
namespace Utilities
{
public class RestorableForm : Form, INotifyPropertyChanged
{
// We invoke this event when the binding needs to be updated.
public event PropertyChangedEventHandler PropertyChanged;
// This stores the last window position and state
private WindowRestoreStateInfo windowRestoreState;
// Now we define the property that we will bind to our settings.
[Browsable(false)] // Don't show it in the Properties list
[SettingsBindable(true)] // But do enable binding to settings
public WindowRestoreStateInfo WindowRestoreState
{
get { return windowRestoreState; }
set
{
windowRestoreState = value;
if (PropertyChanged != null)
{
// If anybody's listening, let them know the
// binding needs to be updated:
PropertyChanged(this,
new PropertyChangedEventArgs("WindowRestoreState"));
}
}
}
protected override void OnClosing(CancelEventArgs e)
{
WindowRestoreState = new WindowRestoreStateInfo();
WindowRestoreState.Bounds
= WindowState == FormWindowState.Normal ?
Bounds : RestoreBounds;
WindowRestoreState.WindowState = WindowState;
base.OnClosing(e);
}
protected override void OnLoad(EventArgs e)
{
base.OnLoad(e);
if (WindowRestoreState != null)
{
Bounds = ConstrainToScreen(WindowRestoreState.Bounds);
WindowState = WindowRestoreState.WindowState;
}
}
// This helper class stores both position and state.
// That way, we only have to set one binding.
public class WindowRestoreStateInfo
{
Rectangle bounds;
public Rectangle Bounds
{
get { return bounds; }
set { bounds = value; }
}
FormWindowState windowState;
public FormWindowState WindowState
{
get { return windowState; }
set { windowState = value; }
}
}
private Rectangle ConstrainToScreen(Rectangle bounds)
{
Screen screen = Screen.FromRectangle(WindowRestoreState.Bounds);
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 Rectangle(left, top, width, height);
}
}
}
Settings Bindings References
SettingsBindableAttribute
INotifyPropertyChanged

The reason why the Form.Size property is not available in the settings binding UI is because this property is marked DesignerSerializationVisibility.Hidden. This means that the designer doesn't know how to serialise it, let alone generate a data binding for it. Instead the Form.ClientSize property is the one that gets serialised.
If you try and get clever by binding Location and ClientSize, you'll see another problem. When you try to resize your form from the left or top edge, you'll see weird behaviour. This is apparently related to the way that two-way data binding works in the context of property sets that mutually affect each other. Both Location and ClientSize eventually call into a common method, SetBoundsCore().
Also, data binding to properties like Location and Size is just not efficient. Each time the user moves or resizes the form, Windows sends hundreds of messages to the form, causing the data binding logic to do a lot of processing, when all you really want is to store the last position and size before the form is closed.
This is a very simplified version of what I do:
private void MyForm_FormClosing(object sender, FormClosingEventArgs e)
{
Properties.Settings.Default.MyState = this.WindowState;
if (this.WindowState == FormWindowState.Normal)
{
Properties.Settings.Default.MySize = this.Size;
Properties.Settings.Default.MyLoc = this.Location;
}
else
{
Properties.Settings.Default.MySize = this.RestoreBounds.Size;
Properties.Settings.Default.MyLoc = this.RestoreBounds.Location;
}
Properties.Settings.Default.Save();
}
private void MyForm_Load(object sender, EventArgs e)
{
this.Size = Properties.Settings.Default.MySize;
this.Location = Properties.Settings.Default.MyLoc;
this.WindowState = Properties.Settings.Default.MyState;
}
Why is this a very simplified version? Because doing this properly is a lot trickier than it looks :-)

One of the reason I imagine size binding is not allowed is because the screen may change between sessions.
Loading the size back when the resolution has reduced could result in the title bar being beyond the limits of the screen.
You also need to be wary of multiple monitor setups, where monitors may no longer be available when you app next runs.

Well I have had a quick play with this and you are correct, while there is no way to directly bind the size of the form to AppSettings, you can add your own values and change the size on load.
I would perhaps recommend that if this is a common feature, you subclass Form and make it automatically prob the App.Config for the forms size settings.
(Or you could roll your own file.. Get it to query an Xml file "formname.settings.xml" or something? - thinking out loud!)..
Heres what I had (very rough, no error checking etc).
App.Config
<?xml version="1.0" encoding="utf-8" ?>
<configuration>
<appSettings>
<add key ="FormHeight" value="500" />
<add key ="FormWidth" value="200"/>
</appSettings>
</configuration>
Form Code
private void Form1_Load(object sender, EventArgs e)
{
string height = ConfigurationManager.AppSettings["FormHeight"];
int h = int.Parse(height);
string width = ConfigurationManager.AppSettings["FormWidth"];
int w = int.Parse(width);
this.Size = new Size(h, w);
}

I agree with Rob Cooper's answer. But I think Martin makes a very good point. Nothing like having users open your application and the app is off-screen!
So in reality, you'll want to combine both answers and bear in mind the current screen dimensions before setting your form's size.