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
请看下面的代码。它是防止一个WPF应用程序有多个实例的一个很好的简单解决方案。
private void Application_Startup(object sender, StartupEventArgs e)
{
Process thisProc = Process.GetCurrentProcess();
if (Process.GetProcessesByName(thisProc.ProcessName).Length > 1)
{
MessageBox.Show("Application running");
Application.Current.Shutdown();
return;
}
var wLogin = new LoginWindow();
if (wLogin.ShowDialog() == true)
{
var wMain = new Main();
wMain.WindowState = WindowState.Maximized;
wMain.Show();
}
else
{
Application.Current.Shutdown();
}
}
其他回答
请看下面的代码。它是防止一个WPF应用程序有多个实例的一个很好的简单解决方案。
private void Application_Startup(object sender, StartupEventArgs e)
{
Process thisProc = Process.GetCurrentProcess();
if (Process.GetProcessesByName(thisProc.ProcessName).Length > 1)
{
MessageBox.Show("Application running");
Application.Current.Shutdown();
return;
}
var wLogin = new LoginWindow();
if (wLogin.ShowDialog() == true)
{
var wMain = new Main();
wMain.WindowState = WindowState.Maximized;
wMain.Show();
}
else
{
Application.Current.Shutdown();
}
}
这是我的两分钱
static class Program
{
[STAThread]
static void Main()
{
bool createdNew;
using (new Mutex(true, "MyApp", out createdNew))
{
if (createdNew) {
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
var mainClass = new SynGesturesLogic();
Application.ApplicationExit += mainClass.tray_exit;
Application.Run();
}
else
{
var current = Process.GetCurrentProcess();
foreach (var process in Process.GetProcessesByName(current.ProcessName).Where(process => process.Id != current.Id))
{
NativeMethods.SetForegroundWindow(process.MainWindowHandle);
break;
}
}
}
}
}
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
}
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。
下面是我使用的一个轻量级解决方案，它允许应用程序将一个已经存在的窗口带到前台，而无需求助于自定义窗口消息或盲目地搜索进程名。
[DllImport("user32.dll")]
static extern bool SetForegroundWindow(IntPtr hWnd);
static readonly string guid = "<Application Guid>";
static void Main()
{
Mutex mutex = null;
if (!CreateMutex(out mutex))
return;
// Application startup code.
Environment.SetEnvironmentVariable(guid, null, EnvironmentVariableTarget.User);
}
static bool CreateMutex(out Mutex mutex)
{
bool createdNew = false;
mutex = new Mutex(false, guid, out createdNew);
if (createdNew)
{
Process process = Process.GetCurrentProcess();
string value = process.Id.ToString();
Environment.SetEnvironmentVariable(guid, value, EnvironmentVariableTarget.User);
}
else
{
string value = Environment.GetEnvironmentVariable(guid, EnvironmentVariableTarget.User);
Process process = null;
int processId = -1;
if (int.TryParse(value, out processId))
process = Process.GetProcessById(processId);
if (process == null || !SetForegroundWindow(process.MainWindowHandle))
MessageBox.Show("Unable to start application. An instance of this application is already running.");
}
return createdNew;
}
编辑:你也可以静态地存储和初始化互斥量和createdNew，但是一旦你完成了它，你需要显式地释放/释放互斥量。就我个人而言，我更喜欢将互斥锁保持在本地，因为即使应用程序在未到达Main结束时就关闭，它也会被自动销毁。
