获取 Window WPF 的高度/宽度

Question

I have the following code

<Window x:Class="Netspot.DigitalSignage.Client.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" WindowStyle="SingleBorderWindow" 
        WindowStartupLocation="CenterScreen"
        WindowState="Normal" Closing="Window_Closing">

Any attempt to get the height / width return NaN or 0.0

Can anyone tell me a way of getting it?

These 2 methods don't work

//Method1
var h = ((System.Windows.Controls.Panel)Application.Current.MainWindow.Content).ActualHeight;
var w = ((System.Windows.Controls.Panel)Application.Current.MainWindow.Content).ActualWidth;

//Method2
double dWidth = -1;
double dHeight = -1;
FrameworkElement pnlClient = this.Content as FrameworkElement;
if (pnlClient != null)
{
     dWidth = pnlClient.ActualWidth;
     dHeight = pnlClient.ActualWidth;
}

The application will not be running full screen.

Answer 1

You can get the width and height that the window was meant to be in the constructor after InitializeComponent has been run, they won't return NaN then, the actual height and width will have to wait until the window has been displayed.

When WindowState == Normal You can do this one from Width / Height after IntializeComponent() .

When WindowState == Maximized You could get the screen resolution for this one with

System.Windows.SystemParameters.PrimaryScreenHeight;
System.Windows.SystemParameters.PrimaryScreenWidth;

Answer 2

You have to try to get the ActualWidth/ActualHeight values once the window is Loaded in the UI. Doing it in Window_Loaded works well.

Answer 3

1.) Subscribe to the window re size event in the code behind:

this.SizeChanged += OnWindowSizeChanged;

2.) Use the SizeChangedEventArgs object 'e' to get the sizes you need:

protected void OnWindowSizeChanged(object sender, SizeChangedEventArgs e)
{
    double newWindowHeight = e.NewSize.Height;
    double newWindowWidth = e.NewSize.Width;
    double prevWindowHeight = e.PreviousSize.Height;
    double prevWindowWidth = e.PreviousSize.Width;
}

Keep in mind this is very general case, you MAY (you may not either) have to do some checking to make sure you have size values of 0.

I used this to resize a list box dynamically as the main window changes. Essentially all I wanted was this control's height to change the same amount the window's height changes so its parent 'panel' looks consistent throughout any window changes.

Here is the code for that, more specific example:

NOTE I have a private instance integer called 'resizeMode' that is set to 0 in the constructor the Window code behind.

Here is the OnWindowSizeChanged event handler:

    protected void OnWindowSizeChanged (object sender, SizeChangedEventArgs e)
    {
        if (e.PreviousSize.Height != 0)
        {
            if (e.HeightChanged)
            {
                double heightChange = e.NewSize.Height - e.PreviousSize.Height;
                if (lbxUninspectedPrints.Height + heightChange > 0)
                {
                    lbxUninspectedPrints.Height = lbxUninspectedPrints.Height + heightChange;
                }
            }
        }
        prevHeight = e.PreviousSize.Height;
    }

Answer 4

XAML

<Grid x:Name="Grid1">
      <Image x:Name="Back_Image" HorizontalAlignment="Left" VerticalAlignment="Top"/>
</Grid>

CS MainWindow() after InitializeComponent();

    Back_Image.Width = Grid1.Width;
    Back_Image.Height = Grid1.Height;

Answer 5

WPF does the creation of controls and windows in a deferred manner. So until the window is displayed for the first time, it might not have gone through layouting yet, thus no ActualWidth / ActualHeight . You can wait until the window is loaded and get the properties then, or yet better bind these properties to a target where you need them. You could also force the layouting via UpdateLayout() .

Just want to add: try to minimize the amount of size dependant logic, it is almost always possible to avoid it. Unless you are writing a layout panel of course.

Answer 6

Notice that when you use controls with 100% of with, they have a NaN size till they are being represented

You can check the ActualHeigh or ActualWidth just when the Loaded event is fired, but never try to verify it before the windows controls are created. Forget the idea to control that in the constructor.

In my oppinion, the best place to control this kind of things is The SizeChanged event

Answer 7

嗨，您可以使用 WPF 获取当前屏幕的高度

System.Windows.SystemParameters.PrimaryScreenHeight

Answer 8

I just add a variable name to my window and then get the width or height of the window i want from its width or height property respectifly.

XAML:

<Window x:Name="exampleName"
   ...
</Window>

C#:

exampleName.Height;

or:

exampleName.Width;

Answer 9

My solution in case of MVVM...

I have a ViewModelBase , which is the base class for all ViewModel of the app.

1.) I created in the ViewModelBase a virtual method, which could be overriten in the child ViewModels.

public virtual void OnWindowSizeChanged(object sender, SizeChangedEventArgs e) {}

2.) The ctr of the MainWindow: Window class

public MainWindow(object dataContext)
{
    InitializeComponent();

    if (dataContext is ViewModelBase)
    {
        this.SizeChanged += ((ViewModelBase)dataContext).OnWindowSizeChanged;
        DataContext = dataContext;
    }
}

3.) Eg. in the MainViewModel , which is extends the ViewModelBase

public override void OnWindowSizeChanged(object sender, SizeChangedEventArgs e)
{
    Console.WriteLine(e.NewSize.Height);
}