在。net下使用c#和WPF(而不是Windows窗体或控制台),创建一个只能作为单个实例运行的应用程序的正确方法是什么?
我知道它与某种叫做互斥的神秘事物有关,我很少能找到有人费心停下来解释其中一个是什么。
代码还需要通知已经运行的实例,用户试图启动第二个实例,如果存在命令行参数,还可能传递任何命令行参数。
在。net下使用c#和WPF(而不是Windows窗体或控制台),创建一个只能作为单个实例运行的应用程序的正确方法是什么?
我知道它与某种叫做互斥的神秘事物有关,我很少能找到有人费心停下来解释其中一个是什么。
代码还需要通知已经运行的实例,用户试图启动第二个实例,如果存在命令行参数,还可能传递任何命令行参数。
当前回答
下面是一个示例,它允许您拥有应用程序的单个实例。当加载任何新实例时,它们将参数传递给正在运行的主实例。
public partial class App : Application
{
private static Mutex SingleMutex;
public static uint MessageId;
private void Application_Startup(object sender, StartupEventArgs e)
{
IntPtr Result;
IntPtr SendOk;
Win32.COPYDATASTRUCT CopyData;
string[] Args;
IntPtr CopyDataMem;
bool AllowMultipleInstances = false;
Args = Environment.GetCommandLineArgs();
// TODO: Replace {00000000-0000-0000-0000-000000000000} with your application's GUID
MessageId = Win32.RegisterWindowMessage("{00000000-0000-0000-0000-000000000000}");
SingleMutex = new Mutex(false, "AppName");
if ((AllowMultipleInstances) || (!AllowMultipleInstances && SingleMutex.WaitOne(1, true)))
{
new Main();
}
else if (Args.Length > 1)
{
foreach (Process Proc in Process.GetProcesses())
{
SendOk = Win32.SendMessageTimeout(Proc.MainWindowHandle, MessageId, IntPtr.Zero, IntPtr.Zero,
Win32.SendMessageTimeoutFlags.SMTO_BLOCK | Win32.SendMessageTimeoutFlags.SMTO_ABORTIFHUNG,
2000, out Result);
if (SendOk == IntPtr.Zero)
continue;
if ((uint)Result != MessageId)
continue;
CopyDataMem = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(Win32.COPYDATASTRUCT)));
CopyData.dwData = IntPtr.Zero;
CopyData.cbData = Args[1].Length*2;
CopyData.lpData = Marshal.StringToHGlobalUni(Args[1]);
Marshal.StructureToPtr(CopyData, CopyDataMem, false);
Win32.SendMessageTimeout(Proc.MainWindowHandle, Win32.WM_COPYDATA, IntPtr.Zero, CopyDataMem,
Win32.SendMessageTimeoutFlags.SMTO_BLOCK | Win32.SendMessageTimeoutFlags.SMTO_ABORTIFHUNG,
5000, out Result);
Marshal.FreeHGlobal(CopyData.lpData);
Marshal.FreeHGlobal(CopyDataMem);
}
Shutdown(0);
}
}
}
public partial class Main : Window
{
private void Window_Loaded(object sender, RoutedEventArgs e)
{
HwndSource Source;
Source = HwndSource.FromHwnd(new WindowInteropHelper(this).Handle);
Source.AddHook(new HwndSourceHook(Window_Proc));
}
private IntPtr Window_Proc(IntPtr hWnd, int Msg, IntPtr wParam, IntPtr lParam, ref bool Handled)
{
Win32.COPYDATASTRUCT CopyData;
string Path;
if (Msg == Win32.WM_COPYDATA)
{
CopyData = (Win32.COPYDATASTRUCT)Marshal.PtrToStructure(lParam, typeof(Win32.COPYDATASTRUCT));
Path = Marshal.PtrToStringUni(CopyData.lpData, CopyData.cbData / 2);
if (WindowState == WindowState.Minimized)
{
// Restore window from tray
}
// Do whatever we want with information
Activate();
Focus();
}
if (Msg == App.MessageId)
{
Handled = true;
return new IntPtr(App.MessageId);
}
return IntPtr.Zero;
}
}
public class Win32
{
public const uint WM_COPYDATA = 0x004A;
public struct COPYDATASTRUCT
{
public IntPtr dwData;
public int cbData;
public IntPtr lpData;
}
[Flags]
public enum SendMessageTimeoutFlags : uint
{
SMTO_NORMAL = 0x0000,
SMTO_BLOCK = 0x0001,
SMTO_ABORTIFHUNG = 0x0002,
SMTO_NOTIMEOUTIFNOTHUNG = 0x0008
}
[DllImport("user32.dll", SetLastError=true, CharSet=CharSet.Auto)]
public static extern uint RegisterWindowMessage(string lpString);
[DllImport("user32.dll")]
public static extern IntPtr SendMessageTimeout(
IntPtr hWnd, uint Msg, IntPtr wParam, IntPtr lParam,
SendMessageTimeoutFlags fuFlags, uint uTimeout, out IntPtr lpdwResult);
}
其他回答
我最喜欢的解决方案来自MVP丹尼尔·沃恩: 强制执行单实例Wpf应用程序
它使用MemoryMappedFile将命令行参数发送给第一个实例:
/// <summary>
/// This class allows restricting the number of executables in execution, to one.
/// </summary>
public sealed class SingletonApplicationEnforcer
{
readonly Action<IEnumerable<string>> processArgsFunc;
readonly string applicationId;
Thread thread;
string argDelimiter = "_;;_";
/// <summary>
/// Gets or sets the string that is used to join
/// the string array of arguments in memory.
/// </summary>
/// <value>The arg delimeter.</value>
public string ArgDelimeter
{
get
{
return argDelimiter;
}
set
{
argDelimiter = value;
}
}
/// <summary>
/// Initializes a new instance of the <see cref="SingletonApplicationEnforcer"/> class.
/// </summary>
/// <param name="processArgsFunc">A handler for processing command line args
/// when they are received from another application instance.</param>
/// <param name="applicationId">The application id used
/// for naming the <seealso cref="EventWaitHandle"/>.</param>
public SingletonApplicationEnforcer(Action<IEnumerable<string>> processArgsFunc,
string applicationId = "DisciplesRock")
{
if (processArgsFunc == null)
{
throw new ArgumentNullException("processArgsFunc");
}
this.processArgsFunc = processArgsFunc;
this.applicationId = applicationId;
}
/// <summary>
/// Determines if this application instance is not the singleton instance.
/// If this application is not the singleton, then it should exit.
/// </summary>
/// <returns><c>true</c> if the application should shutdown,
/// otherwise <c>false</c>.</returns>
public bool ShouldApplicationExit()
{
bool createdNew;
string argsWaitHandleName = "ArgsWaitHandle_" + applicationId;
string memoryFileName = "ArgFile_" + applicationId;
EventWaitHandle argsWaitHandle = new EventWaitHandle(
false, EventResetMode.AutoReset, argsWaitHandleName, out createdNew);
GC.KeepAlive(argsWaitHandle);
if (createdNew)
{
/* This is the main, or singleton application.
* A thread is created to service the MemoryMappedFile.
* We repeatedly examine this file each time the argsWaitHandle
* is Set by a non-singleton application instance. */
thread = new Thread(() =>
{
try
{
using (MemoryMappedFile file = MemoryMappedFile.CreateOrOpen(memoryFileName, 10000))
{
while (true)
{
argsWaitHandle.WaitOne();
using (MemoryMappedViewStream stream = file.CreateViewStream())
{
var reader = new BinaryReader(stream);
string args;
try
{
args = reader.ReadString();
}
catch (Exception ex)
{
Debug.WriteLine("Unable to retrieve string. " + ex);
continue;
}
string[] argsSplit = args.Split(new string[] { argDelimiter },
StringSplitOptions.RemoveEmptyEntries);
processArgsFunc(argsSplit);
}
}
}
}
catch (Exception ex)
{
Debug.WriteLine("Unable to monitor memory file. " + ex);
}
});
thread.IsBackground = true;
thread.Start();
}
else
{
/* Non singleton application instance.
* Should exit, after passing command line args to singleton process,
* via the MemoryMappedFile. */
using (MemoryMappedFile mmf = MemoryMappedFile.OpenExisting(memoryFileName))
{
using (MemoryMappedViewStream stream = mmf.CreateViewStream())
{
var writer = new BinaryWriter(stream);
string[] args = Environment.GetCommandLineArgs();
string joined = string.Join(argDelimiter, args);
writer.Write(joined);
}
}
argsWaitHandle.Set();
}
return !createdNew;
}
}
我在这里找不到一个简单的解决方案,所以我希望有人会喜欢这个:
更新2018-09-20
把这段代码放在Program.cs中:
using System.Diagnostics;
static void Main()
{
Process thisProcess = Process.GetCurrentProcess();
Process[] allProcesses = Process.GetProcessesByName(thisProcess.ProcessName);
if (allProcesses.Length > 1)
{
// Don't put a MessageBox in here because the user could spam this MessageBox.
return;
}
// Optional code. If you don't want that someone runs your ".exe" with a different name:
string exeName = AppDomain.CurrentDomain.FriendlyName;
// in debug mode, don't forget that you don't use your normal .exe name.
// Debug uses the .vshost.exe.
if (exeName != "the name of your executable.exe")
{
// You can add a MessageBox here if you want.
// To point out to users that the name got changed and maybe what the name should be or something like that^^
MessageBox.Show("The executable name should be \"the name of your executable.exe\"",
"Wrong executable name", MessageBoxButtons.OK, MessageBoxIcon.Error);
return;
}
// Following code is default code:
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
Application.Run(new MainForm());
}
简单地使用一个StreamWriter,怎么样?
System.IO.File.StreamWriter OpenFlag = null; //globally
and
try
{
OpenFlag = new StreamWriter(Path.GetTempPath() + "OpenedIfRunning");
}
catch (System.IO.IOException) //file in use
{
Environment.Exit(0);
}
看起来有一个很好的方法来处理这个问题:
WPF单实例应用程序
这提供了一个类,您可以添加它来管理所有互斥量和消息传递的cruff,从而将实现简化到非常简单的程度。
一个新的使用互斥和IPC的东西,也传递任何命令行参数到运行的实例,是WPF单实例应用程序。