代码之家 › 专栏 › 技术社区 › Zach Johnson

强制创建WPF窗口的本机Win32句柄

handle winapi wpf .net c#

Zach Johnson · 技术社区 · 15 年前

我需要访问一些WPF窗口的Win32窗口句柄,以便处理Win32激活消息。我知道我可以用 PresentationSource.FromVisual WindowInteropHelper 获取Win32窗口句柄,但如果尚未创建WPF窗口,则会遇到问题。

PresentationSource.FromVisual 而窗口尚未创建,则返回 PresentationSource 窗内插板 Handle 财产是 IntPtr.Zero

我试过打电话 this.Show() this.Hide() 在我试图接近把手之前。我可以拿到把手,但屏幕上的窗口瞬间闪烁(难看!)。

有人知道如何强制创建WPF窗口吗?在Windows窗体中,这与访问 Form.Handle 财产。

编辑: 最后我得到了克里斯·泰勒的答案。在这里,以防它帮助其他人:

static void InitializeWindow(Window window)
{
    // Get the current values of the properties we are going to change
    double oldWidth = window.Width;
    double oldHeight = window.Height;
    WindowStyle oldWindowStyle = window.WindowStyle;
    bool oldShowInTaskbar = window.ShowInTaskbar;
    bool oldShowActivated = window.ShowActivated;

    // Change the properties to make the window invisible
    window.Width = 0;
    window.Height = 0;
    window.WindowStyle = WindowStyle.None;
    window.ShowInTaskbar = false;
    window.ShowActivated = false;

    // Make WPF create the window's handle
    window.Show();
    window.Hide();

    // Restore the old values
    window.Width = oldWidth;
    window.Height = oldHeight;
    window.WindowStyle = oldWindowStyle;
    window.ShowInTaskbar = oldShowInTaskbar;
    window.ShowActivated = oldShowActivated;
}

// Use it like this:
InitializeWindow(myWpfWindow);

4 回复 | 直到 15 年前

Chris Taylor 15 年前

一个选项是将窗口状态设置为最小化,并且在显示窗口之前不显示在任务栏中。试试这样的。

  IntPtr hWnd;
  WindowInteropHelper helper = new WindowInteropHelper(wnd);

  WindowState prevState = wnd.WindowState;
  bool prevShowInTaskBar = wnd.ShowInTaskbar;

  wnd.ShowInTaskbar = false;
  wnd.WindowState = WindowState.Minimized;
  wnd.Show();
  hWnd = helper.Handle;
  wnd.Hide();

  wnd.ShowInTaskbar = prevShowInTaskBar;
  wnd.WindowState = prevState;

Nazar Grynko 8 年前

使用 WindowInteropHelper.EnsureHandle ,它正是你所需要的。

J Pollack 14 年前

如果WindowInteropHelper的句柄为NULL,我正在寻找一个解决方案。希望这篇文章能提供一些额外的信息来解决这个问题。

一种解决方案是使用:

var window = new Window();
var handle = new WindowInteropHelper(window).EnsureHandle()

这仅适用于.NET Framework 4。

目前我正在使用.NETFramework3.5,所以我需要另一个解决方案。然后我发现了一个带有WindowInteropHelper扩展方法的论坛线程:

#region

using System;
using System.Reflection;
using System.Windows;
using System.Windows.Interop;

#endregion

namespace System.Windows.Interop
{
    /// <summary>
    ///   Provides NetFX 4.0 EnsureHandle method for
    ///   NetFX 3.5 WindowInteropHelper class.
    /// </summary>
    public static class WindowInteropHelperExtension
    {
        /// <summary>
        ///   Creates the HWND of the window if the HWND has not been created yet.
        /// </summary>
        /// <param name = "helper">An instance of WindowInteropHelper class.</param>
        /// <returns>An IntPtr that represents the HWND.</returns>
        /// <remarks>
        ///   Use the EnsureHandle method when you want to separate
        ///   window handle (HWND) creation from the
        ///   actual showing of the managed Window.
        /// </remarks>
        public static IntPtr EnsureHandle(this WindowInteropHelper helper)
        {
            if (helper == null)
                throw new ArgumentNullException("helper");

            if (helper.Handle == IntPtr.Zero)
            {
                var window = (Window) typeof (WindowInteropHelper).InvokeMember(
                    "_window",
                    BindingFlags.GetField |
                    BindingFlags.Instance |
                    BindingFlags.NonPublic,
                    null, helper, null);

                typeof (Window).InvokeMember(
                    "SafeCreateWindow",
                    BindingFlags.InvokeMethod |
                    BindingFlags.Instance |
                    BindingFlags.NonPublic,
                    null, window, null);
            }

            return helper.Handle;
        }
    }
}

http://social.msdn.microsoft.com/Forums/en-MY/wpf/thread/5f89ac58-d2ef-4ac0-aefb-b2826dbef48a

Community Mohan Dere 9 年前

我被困在同一个问题上 J Pollack's answer (因为在我看来它更干净),但是需要一些既能在.NET运行时2.0上运行又能在.NET运行时4.0上运行的东西。

但当我这么做的时候,我却得到了一个丑陋的结局 MissingMethodException 安全创建窗口 在.NET runtime 4.0中不再存在。为了使代码在两个运行时都能工作,我决定捕获MissingMethodException并在.NET 4.0运行时中调用等效的方法,而不是像这样:

    public static IntPtr EnsureHandle(this WindowInteropHelper helper)
    {
        if (helper == null)
            throw new ArgumentNullException("helper");

        if (helper.Handle == IntPtr.Zero)
        {
            var window = (Window)typeof(WindowInteropHelper).InvokeMember(
                "_window",
                BindingFlags.GetField |
                BindingFlags.Instance |
                BindingFlags.NonPublic,
                null, helper, null);

            try
            {
                // SafeCreateWindow only exists in the .NET 2.0 runtime. If we try to
                // invoke this method on the .NET 4.0 runtime it will result in a
                // MissingMethodException, see below.
                typeof(Window).InvokeMember(
                    "SafeCreateWindow",
                    BindingFlags.InvokeMethod |
                    BindingFlags.Instance |
                    BindingFlags.NonPublic,
                    null, window, null);
            }
            catch (MissingMethodException)
            {
                // If we ended up here it means we are running on the .NET 4.0 runtime,
                // where the method we need to call for the handle was renamed/replaced
                // with CreateSourceWindow.
                typeof(Window).InvokeMember(
                    "CreateSourceWindow",
                    BindingFlags.InvokeMethod |
                    BindingFlags.Instance |
                    BindingFlags.NonPublic,
                    null, window, new object[] { false });
            }
        }

        return helper.Handle;
    }