//-----------------------------------------------------------------------
// <copyright file="SingleInstance.cs" company="Microsoft">
// Copyright (c) Microsoft Corporation. All rights reserved.
// </copyright>
// <summary>
// This class checks to make sure that only one instance of
// this application is running at a time.
// </summary>
//-----------------------------------------------------------------------
namespace Microsoft.Shell
{
using System;
using System.Collections;
using System.Collections.Generic;
using System.IO;
using System.Runtime.Remoting;
using System.Runtime.Remoting.Channels;
using System.Runtime.Remoting.Channels.Ipc;
using System.Runtime.Serialization.Formatters;
using System.Threading;
using System.Windows;
using System.Windows.Threading;
using System.Xml.Serialization;
using System.Security;
using System.Runtime.InteropServices;
using System.ComponentModel;
internal enum WM
{
NULL = 0x0000,
CREATE = 0x0001,
DESTROY = 0x0002,
MOVE = 0x0003,
SIZE = 0x0005,
ACTIVATE = 0x0006,
SETFOCUS = 0x0007,
KILLFOCUS = 0x0008,
ENABLE = 0x000A,
SETREDRAW = 0x000B,
SETTEXT = 0x000C,
GETTEXT = 0x000D,
GETTEXTLENGTH = 0x000E,
PAINT = 0x000F,
CLOSE = 0x0010,
QUERYENDSESSION = 0x0011,
QUIT = 0x0012,
QUERYOPEN = 0x0013,
ERASEBKGND = 0x0014,
SYSCOLORCHANGE = 0x0015,
SHOWWINDOW = 0x0018,
ACTIVATEAPP = 0x001C,
SETCURSOR = 0x0020,
MOUSEACTIVATE = 0x0021,
CHILDACTIVATE = 0x0022,
QUEUESYNC = 0x0023,
GETMINMAXINFO = 0x0024,
WINDOWPOSCHANGING = 0x0046,
WINDOWPOSCHANGED = 0x0047,
CONTEXTMENU = 0x007B,
STYLECHANGING = 0x007C,
STYLECHANGED = 0x007D,
DISPLAYCHANGE = 0x007E,
GETICON = 0x007F,
SETICON = 0x0080,
NCCREATE = 0x0081,
NCDESTROY = 0x0082,
NCCALCSIZE = 0x0083,
NCHITTEST = 0x0084,
NCPAINT = 0x0085,
NCACTIVATE = 0x0086,
GETDLGCODE = 0x0087,
SYNCPAINT = 0x0088,
NCMOUSEMOVE = 0x00A0,
NCLBUTTONDOWN = 0x00A1,
NCLBUTTONUP = 0x00A2,
NCLBUTTONDBLCLK = 0x00A3,
NCRBUTTONDOWN = 0x00A4,
NCRBUTTONUP = 0x00A5,
NCRBUTTONDBLCLK = 0x00A6,
NCMBUTTONDOWN = 0x00A7,
NCMBUTTONUP = 0x00A8,
NCMBUTTONDBLCLK = 0x00A9,
SYSKEYDOWN = 0x0104,
SYSKEYUP = 0x0105,
SYSCHAR = 0x0106,
SYSDEADCHAR = 0x0107,
COMMAND = 0x0111,
SYSCOMMAND = 0x0112,
MOUSEMOVE = 0x0200,
LBUTTONDOWN = 0x0201,
LBUTTONUP = 0x0202,
LBUTTONDBLCLK = 0x0203,
RBUTTONDOWN = 0x0204,
RBUTTONUP = 0x0205,
RBUTTONDBLCLK = 0x0206,
MBUTTONDOWN = 0x0207,
MBUTTONUP = 0x0208,
MBUTTONDBLCLK = 0x0209,
MOUSEWHEEL = 0x020A,
XBUTTONDOWN = 0x020B,
XBUTTONUP = 0x020C,
XBUTTONDBLCLK = 0x020D,
MOUSEHWHEEL = 0x020E,
CAPTURECHANGED = 0x0215,
ENTERSIZEMOVE = 0x0231,
EXITSIZEMOVE = 0x0232,
IME_SETCONTEXT = 0x0281,
IME_NOTIFY = 0x0282,
IME_CONTROL = 0x0283,
IME_COMPOSITIONFULL = 0x0284,
IME_SELECT = 0x0285,
IME_CHAR = 0x0286,
IME_REQUEST = 0x0288,
IME_KEYDOWN = 0x0290,
IME_KEYUP = 0x0291,
NCMOUSELEAVE = 0x02A2,
DWMCOMPOSITIONCHANGED = 0x031E,
DWMNCRENDERINGCHANGED = 0x031F,
DWMCOLORIZATIONCOLORCHANGED = 0x0320,
DWMWINDOWMAXIMIZEDCHANGE = 0x0321,
#region Windows 7
DWMSENDICONICTHUMBNAIL = 0x0323,
DWMSENDICONICLIVEPREVIEWBITMAP = 0x0326,
#endregion
USER = 0x0400,
// This is the hard-coded message value used by WinForms for Shell_NotifyIcon.
// It's relatively safe to reuse.
TRAYMOUSEMESSAGE = 0x800, //WM_USER + 1024
APP = 0x8000,
}
[SuppressUnmanagedCodeSecurity]
internal static class NativeMethods
{
/// <summary>
/// Delegate declaration that matches WndProc signatures.
/// </summary>
public delegate IntPtr MessageHandler(WM uMsg, IntPtr wParam, IntPtr lParam, out bool handled);
[DllImport("shell32.dll", EntryPoint = "CommandLineToArgvW", CharSet = CharSet.Unicode)]
private static extern IntPtr _CommandLineToArgvW([MarshalAs(UnmanagedType.LPWStr)] string cmdLine, out int numArgs);
[DllImport("kernel32.dll", EntryPoint = "LocalFree", SetLastError = true)]
private static extern IntPtr _LocalFree(IntPtr hMem);
public static string[] CommandLineToArgvW(string cmdLine)
{
IntPtr argv = IntPtr.Zero;
try
{
int numArgs = 0;
argv = _CommandLineToArgvW(cmdLine, out numArgs);
if (argv == IntPtr.Zero)
{
throw new Win32Exception();
}
var result = new string[numArgs];
for (int i = 0; i < numArgs; i++)
{
IntPtr currArg = Marshal.ReadIntPtr(argv, i * Marshal.SizeOf(typeof(IntPtr)));
result[i] = Marshal.PtrToStringUni(currArg);
}
return result;
}
finally
{
IntPtr p = _LocalFree(argv);
// Otherwise LocalFree failed.
// Assert.AreEqual(IntPtr.Zero, p);
}
}
}
public interface ISingleInstanceApp
{
bool SignalExternalCommandLineArgs(IList<string> args);
}
/// <summary>
/// This class checks to make sure that only one instance of
/// this application is running at a time.
/// </summary>
/// <remarks>
/// Note: this class should be used with some caution, because it does no
/// security checking. For example, if one instance of an app that uses this class
/// is running as Administrator, any other instance, even if it is not
/// running as Administrator, can activate it with command line arguments.
/// For most apps, this will not be much of an issue.
/// </remarks>
public static class SingleInstance<TApplication>
where TApplication: Application , ISingleInstanceApp
{
#region Private Fields
/// <summary>
/// String delimiter used in channel names.
/// </summary>
private const string Delimiter = ":";
/// <summary>
/// Suffix to the channel name.
/// </summary>
private const string ChannelNameSuffix = "SingeInstanceIPCChannel";
/// <summary>
/// Remote service name.
/// </summary>
private const string RemoteServiceName = "SingleInstanceApplicationService";
/// <summary>
/// IPC protocol used (string).
/// </summary>
private const string IpcProtocol = "ipc://";
/// <summary>
/// Application mutex.
/// </summary>
private static Mutex singleInstanceMutex;
/// <summary>
/// IPC channel for communications.
/// </summary>
private static IpcServerChannel channel;
/// <summary>
/// List of command line arguments for the application.
/// </summary>
private static IList<string> commandLineArgs;
#endregion
#region Public Properties
/// <summary>
/// Gets list of command line arguments for the application.
/// </summary>
public static IList<string> CommandLineArgs
{
get { return commandLineArgs; }
}
#endregion
#region Public Methods
/// <summary>
/// Checks if the instance of the application attempting to start is the first instance.
/// If not, activates the first instance.
/// </summary>
/// <returns>True if this is the first instance of the application.</returns>
public static bool InitializeAsFirstInstance( string uniqueName )
{
commandLineArgs = GetCommandLineArgs(uniqueName);
// Build unique application Id and the IPC channel name.
string applicationIdentifier = uniqueName + Environment.UserName;
string channelName = String.Concat(applicationIdentifier, Delimiter, ChannelNameSuffix);
// Create mutex based on unique application Id to check if this is the first instance of the application.
bool firstInstance;
singleInstanceMutex = new Mutex(true, applicationIdentifier, out firstInstance);
if (firstInstance)
{
CreateRemoteService(channelName);
}
else
{
SignalFirstInstance(channelName, commandLineArgs);
}
return firstInstance;
}
/// <summary>
/// Cleans up single-instance code, clearing shared resources, mutexes, etc.
/// </summary>
public static void Cleanup()
{
if (singleInstanceMutex != null)
{
singleInstanceMutex.Close();
singleInstanceMutex = null;
}
if (channel != null)
{
ChannelServices.UnregisterChannel(channel);
channel = null;
}
}
#endregion
#region Private Methods
/// <summary>
/// Gets command line args - for ClickOnce deployed applications, command line args may not be passed directly, they have to be retrieved.
/// </summary>
/// <returns>List of command line arg strings.</returns>
private static IList<string> GetCommandLineArgs( string uniqueApplicationName )
{
string[] args = null;
if (AppDomain.CurrentDomain.ActivationContext == null)
{
// The application was not clickonce deployed, get args from standard API's
args = Environment.GetCommandLineArgs();
}
else
{
// The application was clickonce deployed
// Clickonce deployed apps cannot recieve traditional commandline arguments
// As a workaround commandline arguments can be written to a shared location before
// the app is launched and the app can obtain its commandline arguments from the
// shared location
string appFolderPath = Path.Combine(
Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData), uniqueApplicationName);
string cmdLinePath = Path.Combine(appFolderPath, "cmdline.txt");
if (File.Exists(cmdLinePath))
{
try
{
using (TextReader reader = new StreamReader(cmdLinePath, System.Text.Encoding.Unicode))
{
args = NativeMethods.CommandLineToArgvW(reader.ReadToEnd());
}
File.Delete(cmdLinePath);
}
catch (IOException)
{
}
}
}
if (args == null)
{
args = new string[] { };
}
return new List<string>(args);
}
/// <summary>
/// Creates a remote service for communication.
/// </summary>
/// <param name="channelName">Application's IPC channel name.</param>
private static void CreateRemoteService(string channelName)
{
BinaryServerFormatterSinkProvider serverProvider = new BinaryServerFormatterSinkProvider();
serverProvider.TypeFilterLevel = TypeFilterLevel.Full;
IDictionary props = new Dictionary<string, string>();
props["name"] = channelName;
props["portName"] = channelName;
props["exclusiveAddressUse"] = "false";
// Create the IPC Server channel with the channel properties
channel = new IpcServerChannel(props, serverProvider);
// Register the channel with the channel services
ChannelServices.RegisterChannel(channel, true);
// Expose the remote service with the REMOTE_SERVICE_NAME
IPCRemoteService remoteService = new IPCRemoteService();
RemotingServices.Marshal(remoteService, RemoteServiceName);
}
/// <summary>
/// Creates a client channel and obtains a reference to the remoting service exposed by the server -
/// in this case, the remoting service exposed by the first instance. Calls a function of the remoting service
/// class to pass on command line arguments from the second instance to the first and cause it to activate itself.
/// </summary>
/// <param name="channelName">Application's IPC channel name.</param>
/// <param name="args">
/// Command line arguments for the second instance, passed to the first instance to take appropriate action.
/// </param>
private static void SignalFirstInstance(string channelName, IList<string> args)
{
IpcClientChannel secondInstanceChannel = new IpcClientChannel();
ChannelServices.RegisterChannel(secondInstanceChannel, true);
string remotingServiceUrl = IpcProtocol + channelName + "/" + RemoteServiceName;
// Obtain a reference to the remoting service exposed by the server i.e the first instance of the application
IPCRemoteService firstInstanceRemoteServiceReference = (IPCRemoteService)RemotingServices.Connect(typeof(IPCRemoteService), remotingServiceUrl);
// Check that the remote service exists, in some cases the first instance may not yet have created one, in which case
// the second instance should just exit
if (firstInstanceRemoteServiceReference != null)
{
// Invoke a method of the remote service exposed by the first instance passing on the command line
// arguments and causing the first instance to activate itself
firstInstanceRemoteServiceReference.InvokeFirstInstance(args);
}
}
/// <summary>
/// Callback for activating first instance of the application.
/// </summary>
/// <param name="arg">Callback argument.</param>
/// <returns>Always null.</returns>
private static object ActivateFirstInstanceCallback(object arg)
{
// Get command line args to be passed to first instance
IList<string> args = arg as IList<string>;
ActivateFirstInstance(args);
return null;
}
/// <summary>
/// Activates the first instance of the application with arguments from a second instance.
/// </summary>
/// <param name="args">List of arguments to supply the first instance of the application.</param>
private static void ActivateFirstInstance(IList<string> args)
{
// Set main window state and process command line args
if (Application.Current == null)
{
return;
}
((TApplication)Application.Current).SignalExternalCommandLineArgs(args);
}
#endregion
#region Private Classes
/// <summary>
/// Remoting service class which is exposed by the server i.e the first instance and called by the second instance
/// to pass on the command line arguments to the first instance and cause it to activate itself.
/// </summary>
private class IPCRemoteService : MarshalByRefObject
{
/// <summary>
/// Activates the first instance of the application.
/// </summary>
/// <param name="args">List of arguments to pass to the first instance.</param>
public void InvokeFirstInstance(IList<string> args)
{
if (Application.Current != null)
{
// Do an asynchronous call to ActivateFirstInstance function
Application.Current.Dispatcher.BeginInvoke(
DispatcherPriority.Normal, new DispatcherOperationCallback(SingleInstance<TApplication>.ActivateFirstInstanceCallback), args);
}
}
/// <summary>
/// Remoting Object's ease expires after every 5 minutes by default. We need to override the InitializeLifetimeService class
/// to ensure that lease never expires.
/// </summary>
/// <returns>Always null.</returns>
public override object InitializeLifetimeService()
{
return null;
}
}
#endregion
}
}
Submit an article or tip