如何捕捉窗口大小调整的结束？

Question

如何捕捉窗口大小调整的结束？

c#wpfxamlresizewindow

21

我需要在WPF中捕获endresize事件。

- Mediator

5个回答

16

Reactive Extensions for .NET提供了一些非常酷的功能来处理标准事件模式，包括能够节流事件。我在处理大小改变事件时遇到了类似的问题，虽然解决方案仍然有些“hacky”，但我认为Reactive Extensions提供了一种更优雅的实现方式。这是我的实现：

IObservable<SizeChangedEventArgs> ObservableSizeChanges = Observable
    .FromEventPattern<SizeChangedEventArgs>(this, "SizeChanged")
    .Select(x => x.EventArgs)
    .Throttle(TimeSpan.FromMilliseconds(200));

IDisposable SizeChangedSubscription = ObservableSizeChanges
    .ObserveOn(SynchronizationContext.Current)
    .Subscribe(x => {
        Size_Changed(x);
    });

这将有效地限制SizeChanged事件，使得直到200毫秒（或者您想要等待的时间）没有其他SizeChanged事件被触发，您的Size_Changed方法（在其中可以执行自定义代码）才会被执行。

private void Size_Changed(SizeChangedEventArgs e) {
    // custom code for dealing with end of size changed here
}

- Jesse Carter

6

可以使用@Bohoo提供的非常干净的解决方案，无需计时器，我只是将他的vb.net代码改成了c#代码

     public partial class MainWindow : Window
        {
            public MainWindow()
            {
                InitializeComponent();
                this.Loaded += MainWindow_Loaded;
            }

            private void MainWindow_Loaded(object sender, RoutedEventArgs e)
            {
                // this two line have to be exactly onload
                HwndSource source = HwndSource.FromHwnd(new WindowInteropHelper(this).Handle);
                source.AddHook(new HwndSourceHook(WndProc));
            }


            const int WM_SIZING = 0x214;
            const int WM_EXITSIZEMOVE = 0x232;
            private static bool WindowWasResized = false;


            private static IntPtr WndProc(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)
            {
                if (msg == WM_SIZING)
                {

                    if (WindowWasResized == false)
                    {

                        //    'indicate the the user is resizing and not moving the window
                        WindowWasResized = true;
                    }
                }

                if (msg == WM_EXITSIZEMOVE)
                {

                    // 'check that this is the end of resize and not move operation          
                    if (WindowWasResized == true)
                    {

                        // your stuff to do 
                        Console.WriteLine("End");

                        // 'set it back to false for the next resize/move
                        WindowWasResized = false;
                    }
                }

                return IntPtr.Zero;
            }

    }

- Bilal

5

你可以精确地检测到 WPF 窗口的大小调整结束，而且不需要使用计时器。当用户在窗口大小调整或移动操作结束时释放左键时，本机窗口会接收到 WM_EXITSIZEMOVE 消息。WPF 窗口无法接收此消息，因此我们需要连接一个 WndProc 函数来接收它。我们可以使用 HwndSource 与 WindowInteropHelper 来获取我们的窗口句柄。然后我们将在窗口的Loaded事件（vb.net代码）中添加钩子到我们的 WndProc 函数中。请注意，您需要保留 HTML 标签。

Dim WinSource As HwndSource    

Private Sub WindowLoaded_(sender As Object, e As RoutedEventArgs)

    WinSource = HwndSource.FromHwnd(New WindowInteropHelper(Me).Handle)
    WinSource.AddHook(New HwndSourceHook(AddressOf WndProc))
End Sub

现在，在我们的 WndProc 中，我们将监听 WM_EXITSIZEMOVE 消息：

Const WM_EXITSIZEMOVE As Integer = &H232

Private Function WndProc(hwnd As IntPtr, msg As Integer, wParam As IntPtr, lParam As IntPtr, ByRef handled As Boolean) As IntPtr

    If msg = WM_EXITSIZEMOVE Then

        DoWhatYouNeed()
    End If

    Return IntPtr.Zero
End Function

这种技术及类似技术在这里和这里有解释。

请注意，该函数应返回IntPtr.Zero。此外，在此函数中除了处理您感兴趣的特定消息之外，不要做任何其他事情。

现在，WM_EXITSIZEMOVE也会在移动操作结束时发送，而我们只对调整大小感兴趣。有几种方法可以确定这是调整大小操作的结束。我通过监听WM_SIZING消息（在调整大小期间多次发送）并结合标志来完成。整个解决方案如下：

（注意：不要被此处的代码高亮所困扰，因为对于vb.net来说是错误的）

Dim WinSource As HwndSource
Const WM_SIZING As Integer = &H214
Const WM_EXITSIZEMOVE As Integer = &H232

Dim WindowWasResized As Boolean = False

Private Sub WindowLoaded_(sender As Object, e As RoutedEventArgs)

    WinSource = HwndSource.FromHwnd(New WindowInteropHelper(Me).Handle)
    WinSource.AddHook(New HwndSourceHook(AddressOf WndProc))
End Sub

Private Function WndProc(hwnd As IntPtr, msg As Integer, wParam As IntPtr, lParam As IntPtr, ByRef handled As Boolean) As IntPtr

    If msg = WM_SIZING Then

        If WindowWasResized = False Then

            'indicate the the user is resizing and not moving the window
            WindowWasResized = True
        End If
    End If

    If msg = WM_EXITSIZEMOVE Then

        'check that this is the end of resize and not move operation          
        If WindowWasResized = True Then

             DoWhatYouNeed()

             'set it back to false for the next resize/move
             WindowWasResized = False
        End If            
    End If

    Return IntPtr.Zero
End Function

就是这样。

- Bohoo

我认为我们应该处理 WM_ENTERSIZEMOVE 而不是 WM_SIZING。 - yumetodo

0

对于使用 Rx (System.Reactive) 的 UWP

            //Stop window updates
            rootFrame = new Frame
            {
                HorizontalAlignment = HorizontalAlignment.Left,
                VerticalAlignment = VerticalAlignment.Top,
                Width = Window.Current.Bounds.Width,
                Height = Window.Current.Bounds.Height
            };

            //updates after throttling
            var sizeChangedObservable = Observable.FromEventPattern<WindowSizeChangedEventHandler, WindowSizeChangedEventArgs>(
                      handler => Window.Current.SizeChanged += handler,
                      handler => Window.Current.SizeChanged -= handler);

            sizeChangedObservable.Throttle(TimeSpan.FromSeconds(0.35)).ObserveOnDispatcher(CoreDispatcherPriority.Normal).Subscribe(x =>
            {
                rootFrame.Width = x.EventArgs.Size.Width;
                rootFrame.Height = x.EventArgs.Size.Height;
            });

- Pavlo Datsiuk

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可以查看英文原文，
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- Martin · Accepted Answer

在 WPF 中没有只在调整大小过程结束时触发的事件。 SizeChanged 是与窗口调整大小相关的唯一事件，并且在调整大小过程中会多次触发。

一个完全的 hack（技巧）是在 SizeChanged 事件触发时不断设置一个计时器。然后，直到调整大小结束时计时器才有机会运行，并在此时执行您的一次性处理。

public MyUserControl()
{
    _resizeTimer.Tick += _resizeTimer_Tick;
}

DispatcherTimer _resizeTimer = new DispatcherTimer { Interval = new TimeSpan(0, 0, 0, 0, 1500), IsEnabled = false };

private void UserControl_SizeChanged(object sender, SizeChangedEventArgs e)
{
    _resizeTimer.IsEnabled = true;
    _resizeTimer.Stop();
    _resizeTimer.Start();
}

void _resizeTimer_Tick(object sender, EventArgs e)
{
    _resizeTimer.IsEnabled = false;    

    //Do end of resize processing
}