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
永远不要使用命名互斥来实现单实例应用程序(至少在生产代码中不要这样做)。恶意代码可以很容易地DoS(拒绝服务)你的屁股…
其他回答
永远不要使用命名互斥来实现单实例应用程序(至少在生产代码中不要这样做)。恶意代码可以很容易地DoS(拒绝服务)你的屁股…
好吧,我有一个一次性的类,对于大多数用例来说很容易:
像这样使用它:
static void Main()
{
using (SingleInstanceMutex sim = new SingleInstanceMutex())
{
if (sim.IsOtherInstanceRunning)
{
Application.Exit();
}
// Initialize program here.
}
}
下面就是:
/// <summary>
/// Represents a <see cref="SingleInstanceMutex"/> class.
/// </summary>
public partial class SingleInstanceMutex : IDisposable
{
#region Fields
/// <summary>
/// Indicator whether another instance of this application is running or not.
/// </summary>
private bool isNoOtherInstanceRunning;
/// <summary>
/// The <see cref="Mutex"/> used to ask for other instances of this application.
/// </summary>
private Mutex singleInstanceMutex = null;
/// <summary>
/// An indicator whether this object is beeing actively disposed or not.
/// </summary>
private bool disposed;
#endregion
#region Constructor
/// <summary>
/// Initializes a new instance of the <see cref="SingleInstanceMutex"/> class.
/// </summary>
public SingleInstanceMutex()
{
this.singleInstanceMutex = new Mutex(true, Assembly.GetCallingAssembly().FullName, out this.isNoOtherInstanceRunning);
}
#endregion
#region Properties
/// <summary>
/// Gets an indicator whether another instance of the application is running or not.
/// </summary>
public bool IsOtherInstanceRunning
{
get
{
return !this.isNoOtherInstanceRunning;
}
}
#endregion
#region Methods
/// <summary>
/// Closes the <see cref="SingleInstanceMutex"/>.
/// </summary>
public void Close()
{
this.ThrowIfDisposed();
this.singleInstanceMutex.Close();
}
public void Dispose()
{
this.Dispose(true);
GC.SuppressFinalize(this);
}
private void Dispose(bool disposing)
{
if (!this.disposed)
{
/* Release unmanaged ressources */
if (disposing)
{
/* Release managed ressources */
this.Close();
}
this.disposed = true;
}
}
/// <summary>
/// Throws an exception if something is tried to be done with an already disposed object.
/// </summary>
/// <remarks>
/// All public methods of the class must first call this.
/// </remarks>
public void ThrowIfDisposed()
{
if (this.disposed)
{
throw new ObjectDisposedException(this.GetType().Name);
}
}
#endregion
}
我添加了一个sendMessage方法到NativeMethods类。
显然,如果应用程序没有显示在任务栏中,postmessage方法不会工作,但是使用sendmessage方法解决了这个问题。
class NativeMethods
{
public const int HWND_BROADCAST = 0xffff;
public static readonly int WM_SHOWME = RegisterWindowMessage("WM_SHOWME");
[DllImport("user32")]
public static extern bool PostMessage(IntPtr hwnd, int msg, IntPtr wparam, IntPtr lparam);
[DllImport("user32.dll", CharSet = CharSet.Auto)]
public static extern IntPtr SendMessage(IntPtr hWnd, int Msg, IntPtr wParam, IntPtr lParam);
[DllImport("user32")]
public static extern int RegisterWindowMessage(string message);
}
通常,这是我用于单实例Windows窗体应用程序的代码:
[STAThread]
public static void Main()
{
String assemblyName = Assembly.GetExecutingAssembly().GetName().Name;
using (Mutex mutex = new Mutex(false, assemblyName))
{
if (!mutex.WaitOne(0, false))
{
Boolean shownProcess = false;
Process currentProcess = Process.GetCurrentProcess();
foreach (Process process in Process.GetProcessesByName(currentProcess.ProcessName))
{
if (!process.Id.Equals(currentProcess.Id) && process.MainModule.FileName.Equals(currentProcess.MainModule.FileName) && !process.MainWindowHandle.Equals(IntPtr.Zero))
{
IntPtr windowHandle = process.MainWindowHandle;
if (NativeMethods.IsIconic(windowHandle))
NativeMethods.ShowWindow(windowHandle, ShowWindowCommand.Restore);
NativeMethods.SetForegroundWindow(windowHandle);
shownProcess = true;
}
}
if (!shownProcess)
MessageBox.Show(String.Format(CultureInfo.CurrentCulture, "An instance of {0} is already running!", assemblyName), assemblyName, MessageBoxButtons.OK, MessageBoxIcon.Asterisk, MessageBoxDefaultButton.Button1, (MessageBoxOptions)0);
}
else
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
Application.Run(new Form());
}
}
}
本地组件的位置:
[DllImport("User32.dll", CharSet = CharSet.Unicode, ExactSpelling = true, SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
internal static extern Boolean IsIconic([In] IntPtr windowHandle);
[DllImport("User32.dll", CharSet = CharSet.Unicode, ExactSpelling = true, SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
internal static extern Boolean SetForegroundWindow([In] IntPtr windowHandle);
[DllImport("User32.dll", CharSet = CharSet.Unicode, ExactSpelling = true, SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
internal static extern Boolean ShowWindow([In] IntPtr windowHandle, [In] ShowWindowCommand command);
public enum ShowWindowCommand : int
{
Hide = 0x0,
ShowNormal = 0x1,
ShowMinimized = 0x2,
ShowMaximized = 0x3,
ShowNormalNotActive = 0x4,
Minimize = 0x6,
ShowMinimizedNotActive = 0x7,
ShowCurrentNotActive = 0x8,
Restore = 0x9,
ShowDefault = 0xA,
ForceMinimize = 0xB
}
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);
}