无法从 Win7 x64 上的 32 位进程启动屏幕键盘 (osk.exe)

Question

90% 的时间我无法从 Win7 x64 上的 32 位进程启动 osk.exe。最初的代码只是使用：

Process.Launch("osk.exe");

由于目录虚拟化，这在 x64 上不起作用。我认为这不是问题，我只需禁用虚拟化，启动应用程序，然后再次启用它，我认为这是正确的做事方式。我还添加了一些代码，如果键盘已被最小化（效果很好），则可以恢复键盘 - 代码（在示例 WPF 应用程序中）现在如下所示：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;using System.Diagnostics;
using System.Runtime.InteropServices;

namespace KeyboardTest
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        [DllImport("kernel32.dll", SetLastError = true)]
        private static extern bool Wow64DisableWow64FsRedirection(ref IntPtr ptr);
        [DllImport("kernel32.dll", SetLastError = true)]
        public static extern bool Wow64RevertWow64FsRedirection(IntPtr ptr);

        private const UInt32 WM_SYSCOMMAND = 0x112;
        private const UInt32 SC_RESTORE = 0xf120;
        [DllImport("user32.dll", CharSet = CharSet.Auto)]
        static extern IntPtr SendMessage(IntPtr hWnd, UInt32 Msg, IntPtr wParam, IntPtr lParam);

        private string OnScreenKeyboadApplication = "osk.exe";

        public MainWindow()
        {
            InitializeComponent();
        }

        private void KeyboardButton_Click(object sender, RoutedEventArgs e)
        {
            // Get the name of the On screen keyboard
            string processName = System.IO.Path.GetFileNameWithoutExtension(OnScreenKeyboadApplication);

            // Check whether the application is not running 
            var query = from process in Process.GetProcesses()
                        where process.ProcessName == processName
                        select process;

            var keyboardProcess = query.FirstOrDefault();

            // launch it if it doesn't exist
            if (keyboardProcess == null)
            {
                IntPtr ptr = new IntPtr(); ;
                bool sucessfullyDisabledWow64Redirect = false;

                // Disable x64 directory virtualization if we're on x64,
                // otherwise keyboard launch will fail.
                if (System.Environment.Is64BitOperatingSystem)
                {
                    sucessfullyDisabledWow64Redirect = Wow64DisableWow64FsRedirection(ref ptr);
                }

                // osk.exe is in windows/system folder. So we can directky call it without path
                using (Process osk = new Process())
                {
                    osk.StartInfo.FileName = OnScreenKeyboadApplication;
                    osk.Start();
                    osk.WaitForInputIdle(2000);
                }

                // Re-enable directory virtualisation if it was disabled.
                if (System.Environment.Is64BitOperatingSystem)
                    if (sucessfullyDisabledWow64Redirect)
                        Wow64RevertWow64FsRedirection(ptr);
            }
            else
            {
                // Bring keyboard to the front if it's already running
                var windowHandle = keyboardProcess.MainWindowHandle;
                SendMessage(windowHandle, WM_SYSCOMMAND, new IntPtr(SC_RESTORE), new IntPtr(0));
            }
        }
    }
}

但是这段代码，大多数时候，在osk.Start() 上抛出以下异常：

找不到指定的程序 在 System.Diagnostics.Process.StartWithShellExecuteEx(ProcessStartInfo startInfo)

我尝试在 osk.Start 行周围放置较长的 Thread.Sleep 命令，以确保它不是竞争条件，但同样的问题仍然存在。谁能发现我做错了什么，或为此提供替代解决方案？ 似乎可以正常启动记事本，只是无法使用屏幕键盘。

Answer 1

在 64 位操作系统上运行的 32 位应用程序应该启动 64 位版本的 osk.exe。 下面你会看到一段用 C# 编写的代码，用于启动正确的屏幕键盘。

    private static void ShowKeyboard()
    {
        var path64 = @"C:\Windows\winsxs\amd64_microsoft-windows-osk_31bf3856ad364e35_6.1.7600.16385_none_06b1c513739fb828\osk.exe";
        var path32 = @"C:\windows\system32\osk.exe";
        var path = (Environment.Is64BitOperatingSystem) ? path64 : path32;
        Process.Start(path);
    }

Answer 2

对于您收到的确切错误消息，我没有非常可靠的解释。但是禁用重定向会弄乱 .NET 框架。默认情况下，Process.Start() P/Invoke ShellExecuteEx() API 函数来启动进程。该函数位于 shell32.dll 中，如果以前没有加载，则可能必须加载该 DLL。禁用重定向时会出错。

解决方法是将 ProcessStartInfo.UseShellExecute 设置为 false。你在这里不需要它。

显然，禁用重定向是一种冒险的方法，其副作用是您无法真正预测的。有很多 DLL 可以按需加载。您使用 Platform Target 编译的一个非常小的帮助程序 EXE = 任何 CPU 都可以解决您的问题。

Answer 3

某些事情在后台发生，需要您从 MTA 线程启动 osk.exe。原因似乎是对Wow64DisableWow64FsRedirection 的调用仅影响当前线程。但是，在某些情况下，Process.Start 会从一个单独的线程创建新进程，例如当UseShellExecute 设置为 false 以及从 STA 线程调用时。

以下代码检查单元状态，然后确保从 MTA 线程启动屏幕键盘：

using System;
using System.Diagnostics;
using System.IO;
using System.Runtime.InteropServices;
using System.Threading;

class Program
{
    [DllImport("kernel32.dll", SetLastError = true)]
    private static extern bool Wow64DisableWow64FsRedirection(ref IntPtr ptr);
    [DllImport("kernel32.dll", SetLastError = true)]
    public static extern bool Wow64RevertWow64FsRedirection(IntPtr ptr);


    [DllImport("user32.dll", CharSet = CharSet.Auto)]
    static extern IntPtr SendMessage(IntPtr hWnd, 
        UInt32 Msg, 
        IntPtr wParam, 
        IntPtr lParam);
    private const UInt32 WM_SYSCOMMAND = 0x112;
    private const UInt32 SC_RESTORE = 0xf120;

    private const string OnScreenKeyboardExe = "osk.exe";

    [STAThread]
    static void Main(string[] args)
    {
        Process[] p = Process.GetProcessesByName(
            Path.GetFileNameWithoutExtension(OnScreenKeyboardExe));

        if (p.Length == 0)
        {
            // we must start osk from an MTA thread
            if (Thread.CurrentThread.GetApartmentState() == ApartmentState.STA)
            {
                ThreadStart start = new ThreadStart(StartOsk);
                Thread thread = new Thread(start);
                thread.SetApartmentState(ApartmentState.MTA);
                thread.Start();
                thread.Join();
            }
            else
            {
                StartOsk();
            }
        }
        else
        {
            // there might be a race condition if the process terminated 
            // meanwhile -> proper exception handling should be added
            //
            SendMessage(p[0].MainWindowHandle, 
                WM_SYSCOMMAND, new IntPtr(SC_RESTORE), new IntPtr(0));
        }
    }

    static void StartOsk()
    {
        IntPtr ptr = new IntPtr(); ;
        bool sucessfullyDisabledWow64Redirect = false;

        // Disable x64 directory virtualization if we're on x64,
        // otherwise keyboard launch will fail.
        if (System.Environment.Is64BitOperatingSystem)
        {
            sucessfullyDisabledWow64Redirect = 
                Wow64DisableWow64FsRedirection(ref ptr);
        }


        ProcessStartInfo psi = new ProcessStartInfo();
        psi.FileName = OnScreenKeyboardExe;
        // We must use ShellExecute to start osk from the current thread
        // with psi.UseShellExecute = false the CreateProcessWithLogon API 
        // would be used which handles process creation on a separate thread 
        // where the above call to Wow64DisableWow64FsRedirection would not 
        // have any effect.
        //
        psi.UseShellExecute = true;
        Process.Start(psi);

        // Re-enable directory virtualisation if it was disabled.
        if (System.Environment.Is64BitOperatingSystem)
            if (sucessfullyDisabledWow64Redirect)
                Wow64RevertWow64FsRedirection(ptr);
    }
}

Answer 4

这是我的代码

            var path64 = Path.Combine(Directory.GetDirectories(Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Windows), "winsxs"), "amd64_microsoft-windows-osk_*")[0], "osk.exe");
            var path32 = @"C:\windows\system32\osk.exe";
            var path = (Environment.Is64BitOperatingSystem) ? path64 : path32;
            if(File.Exists(path))
            {
                Process.Start(path);
            }

Answer 5

笨方法：

在旁边运行这个批处理文件（从 64 位资源管理器开始）：

:实验室0 超时/T 1 >nul 如果存在 oskstart.tmp 转到 lab2 转到实验室0 :实验室2 删除 oskstart.tmp 操作系统 转到实验室0

在需要键盘时创建文件 oskstart.tmp

Answer 6

对于那些面临“无法启动屏幕键盘”的用户，请将项目的 Platform Target 更改为 Any CPU。