在 Windows 窗体中,我只需覆盖 WndProc,并在消息进入时开始处理它们。
WndProc
谁能给我举个例子说明如何在 WPF 中实现同样的功能?
WPF 不能在 WinForms 类型 wndprocs 上操作
您可以在适当的 WPF 元素中托管一个 HWndHost,然后覆盖 HWndHost 的 wndproc,但是 AFAIK 是最接近的。
http://msdn.microsoft.com/en-us/library/ms742522.aspx
Http://blogs.msdn.com/nickkramer/archive/2006/03/18/554235.aspx
简而言之,你不能。WndProc 通过在 Win32级别上将消息传递给 HWND 来工作。WPF 窗口没有 HWND,因此不能参与 WndProc 消息。基本 WPF 消息循环确实位于 WndProc 之上,但是它将它们从核心 WPF 逻辑抽象出来。
您可以使用 HWndHost 并获取它的 WndProc。然而,这几乎肯定不是您想要做的。在大多数情况下,WPF 不在 HWND 和 WndProc 上运行。您的解决方案几乎肯定依赖于对 WPF 进行更改,而不是在 WndProc 中进行更改。
在 WPF 中使用 WndProc 处理消息的方法有很多(例如使用 HwndSource 等) ,但通常这些技术都是为了与不能直接通过 WPF 处理的消息进行互操作而保留的。大多数 WPF 控件甚至不是 Win32(扩展为 Windows)中的窗口。表单) ,所以他们不会有 WndProcs。
事实上,据我所知,这样的事情确实可能在 WPF 使用 HwndSource和 HwndSourceHook。以 MSDN 上的这个帖子为例。(相关代码如下)
HwndSource
HwndSourceHook
// 'this' is a Window HwndSource source = HwndSource.FromHwnd(new WindowInteropHelper(this).Handle); source.AddHook(new HwndSourceHook(WndProc)); private static IntPtr WndProc(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled) { // do stuff return IntPtr.Zero; }
现在,我不太确定为什么要在 WPF 应用程序中处理 Windows Messaging 消息(除非它是与另一个 WinForms 应用程序协同工作的最明显形式)。WPF 的设计思想和 API 的本质与 WinForms 非常不同,所以我建议你更多地熟悉 WPF,看看 为什么到底有没有 WndProc 的等价物。
HwndSource src = HwndSource.FromHwnd(new WindowInteropHelper(this).Handle); src.AddHook(new HwndSourceHook(WndProc)); ....... public IntPtr WndProc(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled) { if(msg == THEMESSAGEIMLOOKINGFOR) { //Do something here } return IntPtr.Zero; }
您可以通过包含名为 HwndSource的类的 System.Windows.Interop命名空间来实现这一点。
System.Windows.Interop
使用此
using System; using System.Windows; using System.Windows.Interop; namespace WpfApplication1 { public partial class Window1 : Window { public Window1() { InitializeComponent(); } protected override void OnSourceInitialized(EventArgs e) { base.OnSourceInitialized(e); HwndSource source = PresentationSource.FromVisual(this) as HwndSource; source.AddHook(WndProc); } private IntPtr WndProc(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled) { // Handle messages... return IntPtr.Zero; } } }
完全取自优秀的博客文章: 在 WPF 应用程序中使用自定义 WndProc 作者: Steve Rands
这里有一个关于使用行为重写 WindProc 的链接: http://10rem.net/blog/2010/01/09/a-wpf-behavior-for-window-resize-events-in-net-35
[编辑: 迟到总比不到好]下面是我基于以上链接的实现。虽然我会重新考虑这个问题,但是我更喜欢 AddHook 的实现。我可能会改用那个。
对我来说,我想知道窗户什么时候调整大小,还有一些其他的事情。这个实现挂接到 Windowxaml 并发送事件。
using System; using System.Windows.Interactivity; using System.Windows; // For Window in behavior using System.Windows.Interop; // For Hwnd public class WindowResizeEvents : Behavior<Window> { public event EventHandler Resized; public event EventHandler Resizing; public event EventHandler Maximized; public event EventHandler Minimized; public event EventHandler Restored; public static DependencyProperty IsAppAskCloseProperty = DependencyProperty.RegisterAttached("IsAppAskClose", typeof(bool), typeof(WindowResizeEvents)); public Boolean IsAppAskClose { get { return (Boolean)this.GetValue(IsAppAskCloseProperty); } set { this.SetValue(IsAppAskCloseProperty, value); } } // called when the behavior is attached // hook the wndproc protected override void OnAttached() { base.OnAttached(); AssociatedObject.Loaded += (s, e) => { WireUpWndProc(); }; } // call when the behavior is detached // clean up our winproc hook protected override void OnDetaching() { RemoveWndProc(); base.OnDetaching(); } private HwndSourceHook _hook; private void WireUpWndProc() { HwndSource source = HwndSource.FromVisual(AssociatedObject) as HwndSource; if (source != null) { _hook = new HwndSourceHook(WndProc); source.AddHook(_hook); } } private void RemoveWndProc() { HwndSource source = HwndSource.FromVisual(AssociatedObject) as HwndSource; if (source != null) { source.RemoveHook(_hook); } } private const Int32 WM_EXITSIZEMOVE = 0x0232; private const Int32 WM_SIZING = 0x0214; private const Int32 WM_SIZE = 0x0005; private const Int32 SIZE_RESTORED = 0x0000; private const Int32 SIZE_MINIMIZED = 0x0001; private const Int32 SIZE_MAXIMIZED = 0x0002; private const Int32 SIZE_MAXSHOW = 0x0003; private const Int32 SIZE_MAXHIDE = 0x0004; private const Int32 WM_QUERYENDSESSION = 0x0011; private const Int32 ENDSESSION_CLOSEAPP = 0x1; private const Int32 WM_ENDSESSION = 0x0016; private IntPtr WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, ref Boolean handled) { IntPtr result = IntPtr.Zero; switch (msg) { case WM_SIZING: // sizing gets interactive resize OnResizing(); break; case WM_SIZE: // size gets minimize/maximize as well as final size { int param = wParam.ToInt32(); switch (param) { case SIZE_RESTORED: OnRestored(); break; case SIZE_MINIMIZED: OnMinimized(); break; case SIZE_MAXIMIZED: OnMaximized(); break; case SIZE_MAXSHOW: break; case SIZE_MAXHIDE: break; } } break; case WM_EXITSIZEMOVE: OnResized(); break; // Windows is requesting app to close. // See http://msdn.microsoft.com/en-us/library/windows/desktop/aa376890%28v=vs.85%29.aspx. // Use the default response (yes). case WM_QUERYENDSESSION: IsAppAskClose = true; break; } return result; } private void OnResizing() { if (Resizing != null) Resizing(AssociatedObject, EventArgs.Empty); } private void OnResized() { if (Resized != null) Resized(AssociatedObject, EventArgs.Empty); } private void OnRestored() { if (Restored != null) Restored(AssociatedObject, EventArgs.Empty); } private void OnMinimized() { if (Minimized != null) Minimized(AssociatedObject, EventArgs.Empty); } private void OnMaximized() { if (Maximized != null) Maximized(AssociatedObject, EventArgs.Empty); } } <Window x:Class="MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity" xmlns:behaviors="clr-namespace:RapidCoreConfigurator._Behaviors" Title="name" Height="500" Width="750" BorderBrush="Transparent"> <i:Interaction.Behaviors> <behaviors:WindowResizeEvents IsAppAskClose="{Binding IsRequestClose, Mode=OneWayToSource}" Resized="Window_Resized" Resizing="Window_Resizing" /> </i:Interaction.Behaviors> ... </Window>
如果你不介意引用 WinForms,你可以使用一个更加面向 MVVM 的解决方案,它不会将服务和视图耦合起来。您需要创建并初始化一个 System。窗户。表格。NativeWindow,它是一个可以接收消息的轻量级窗口。
public abstract class WinApiServiceBase : IDisposable { /// <summary> /// Sponge window absorbs messages and lets other services use them /// </summary> private sealed class SpongeWindow : NativeWindow { public event EventHandler<Message> WndProced; public SpongeWindow() { CreateHandle(new CreateParams()); } protected override void WndProc(ref Message m) { WndProced?.Invoke(this, m); base.WndProc(ref m); } } private static readonly SpongeWindow Sponge; protected static readonly IntPtr SpongeHandle; static WinApiServiceBase() { Sponge = new SpongeWindow(); SpongeHandle = Sponge.Handle; } protected WinApiServiceBase() { Sponge.WndProced += LocalWndProced; } private void LocalWndProced(object sender, Message message) { WndProc(message); } /// <summary> /// Override to process windows messages /// </summary> protected virtual void WndProc(Message message) { } public virtual void Dispose() { Sponge.WndProced -= LocalWndProced; } }
使用海绵句柄注册您感兴趣的消息,然后覆盖 WndProc 来处理它们:
public class WindowsMessageListenerService : WinApiServiceBase { protected override void WndProc(Message message) { Debug.WriteLine(message.msg); } }
唯一的缺点是必须包含 System。窗户。表单引用,但除此之外,这是一个非常封装的解决方案。
关于这方面的更多信息可以阅读 给你
您可以附加到内置 Win32类的“ SystemEvents”类:
using Microsoft.Win32;
在 WPF 窗口类中:
SystemEvents.PowerModeChanged += SystemEvents_PowerModeChanged; SystemEvents.SessionSwitch += SystemEvents_SessionSwitch; SystemEvents.SessionEnding += SystemEvents_SessionEnding; SystemEvents.SessionEnded += SystemEvents_SessionEnded; private async void SystemEvents_PowerModeChanged(object sender, PowerModeChangedEventArgs e) { await vm.PowerModeChanged(e.Mode); } private async void SystemEvents_PowerModeChanged(object sender, PowerModeChangedEventArgs e) { await vm.PowerModeChanged(e.Mode); } private async void SystemEvents_SessionSwitch(object sender, SessionSwitchEventArgs e) { await vm.SessionSwitch(e.Reason); } private async void SystemEvents_SessionEnding(object sender, SessionEndingEventArgs e) { if (e.Reason == SessionEndReasons.Logoff) { await vm.UserLogoff(); } } private async void SystemEvents_SessionEnded(object sender, SessionEndedEventArgs e) { if (e.Reason == SessionEndReasons.Logoff) { await vm.UserLogoff(); } }