如何在WinForms應用程序的另一個流程實例中調用方法？

Question

我正在使用一個使用Mutex的應用程序來確保它是系統上運行的應用程序的唯一實例。

當另一個應用程序實例嘗試啟動時，我想要一個方法在原始實例中運行。

我可以從應用程序的另一個實例調用我的應用程序中的特定方法嗎？

我發現了一些使用RegisterWindowMessage / PostMessage Win32 API的示例，通過將消息發送到HWND_BROADCAST，但我無法讓它們工作，我在其他地方讀過使用HWND_BROADCAST可能很危險。

有沒有更好的方法來做這個不涉及需要在特權模式下運行的應用程序？

Answer 1

這是我寫的一個小幫手。

要使用它：

var pipeListener = new NamedPipeListener<String>(); // instantiate an instance
pipeListener.MessageReceived += (sender, e) => MessageBox.Show(e.Message); // when a message is received, show a messagebox with the message
pipeListener.Error += (sender, e) => MessageBox.Show("Error ({0}): {1}", e.ErrorType, e.Exception.Message); // oh noes!
pipeListener.Start(); // when you're ready, start listening

從另一個過程：

NamedPipeListener<String>.SendMessage("Howdy howdy howdy");

請注意，它使用PipeListener的全名作為管道的默認名稱。 如果您需要更加謹慎，請使用帶有管道名稱的構造函數重載。

這是班級：

using System;
using System.IO.Pipes;
using System.Runtime.Serialization.Formatters.Binary;

namespace FunWithNamedPipes
{
    /// <summary>Contains event data for <see cref="NamedPipeMessageReceiveHandler{TMessage}" /> events.</summary>
    /// <typeparam name="TMessage"></typeparam>
    public class NamedPipeListenerMessageReceivedEventArgs<TMessage> : EventArgs
    {
        /// <summary>Initializes an instance of <see cref="NamedPipeListenerMessageReceivedEventArgs{TMessage}" /> with the specified <paramref name="message" />.</summary>
        /// <param name="message">The message passed by the event.</param>
        public NamedPipeListenerMessageReceivedEventArgs(TMessage message)
        {
            this.Message = message;
        }

        /// <summary>Gets the message passed by the event.</summary>
        public TMessage Message { get; private set; }
    }

    /// <summary>Contains event data for <see cref="NamedPipeListenerErrorEventHandler" /> events.</summary>
    public class NamedPipeListenerErrorEventArgs : EventArgs
    {
        /// <summary>Initializes an instance of <see cref="NamedPipeListenerErrorEventArgs" /> with the specified <paramref name="errorType" /> and <paramref name="exception" />.</summary>
        /// <param name="errorType">A <see cref="NamedPipeListenerErrorType" /> describing the part of the listener process where the error was caught.</param>
        /// <param name="ex">The <see cref="Exception" /> that was thrown.</param>
        public NamedPipeListenerErrorEventArgs(NamedPipeListenerErrorType errorType, Exception ex)
        {
            this.ErrorType = errorType;
            this.Exception = ex;
        }

        /// <summary>Gets a <see cref="NamedPipeListenerErrorType" /> describing the part of the listener process where the error was caught.</summary>
        public NamedPipeListenerErrorType ErrorType { get; private set; }

        /// <summary>Gets the <see cref="Exception" /> that was caught.</summary>
        public Exception Exception { get; private set; }
    }

    /// <summary>Represents a method that will handle an event where a message is received via named pipes.</summary>
    /// <typeparam name="TMessage">The type of message that will be received.</typeparam>
    /// <param name="sender">The source of the event.</param>
    /// <param name="e">The event data passed by the event, which includes the message that was received.</param>
    public delegate void NamedPipeMessageReceivedHandler<TMessage>(Object sender, NamedPipeListenerMessageReceivedEventArgs<TMessage> e);

    /// <summary>Represents a method that will handle an event that is fired when an exception is caught.</summary>
    /// <param name="sender">The source of the event.</param>
    /// <param name="e">The event data passed by the event, included the error type and exception that was caught.</param>
    public delegate void NamedPipeMessageErrorHandler(Object sender, NamedPipeListenerErrorEventArgs e);

    /// <summary>Includes different types of errors that describe where in the listening process an exception was caught.</summary>
    public enum NamedPipeListenerErrorType : byte
    {
        /// <summary>Indicates that an exception was caught while calling <see cref="NamedPipeServerStream.BeginWaitForConnection" />.</summary>
        BeginWaitForConnection = 1,

        /// <summary>Indicates that an exception was caught while calling <see cref="NamedPipeServerStream.EndWaitForConnection" />.</summary>
        EndWaitForConnection = 2,

        /// <summary>Indicates that an exception was caught while deserializing a message received from the named pipe.</summary>
        DeserializeMessage = 3,

        /// <summary>Indicates that an exception was caught while closing or disposing a used named pipe.</summary>
        CloseAndDisposePipe = 4,

        /// <summary>Indicates that an exception was caught while invoking the <see cref="NamedPipeListener{TMessage}.MessageReceived"/> event.</summary>
        NotifyMessageReceived = 5
    }

    /// <summary>A helper class for sending and receiving messages using named pipes.</summary>
    /// <typeparam name="TMessage">The type of message that will be sent or received.</typeparam>
    public class NamedPipeListener<TMessage> : IDisposable
    {
        /// <summary>Occurs when a message is received.</summary>
        public event NamedPipeMessageReceivedHandler<TMessage> MessageReceived;

        /// <summary>Occurs when an exception is caught.</summary>
        public event NamedPipeMessageErrorHandler Error;

        static readonly String DEFAULT_PIPENAME = typeof(NamedPipeListener<TMessage>).FullName;
        static readonly BinaryFormatter formatter = new BinaryFormatter();

        NamedPipeServerStream pipeServer;

        /// <summary>Initializes a new instance of <see cref="NamedPipeListener{TMessage}" /> using the specified <paramref name="pipeName" />.</summary>
        /// <param name="pipeName">The name of the named pipe that will be used to listen on.</param>
        public NamedPipeListener(String pipeName)
        {
            this.PipeName = pipeName;
        }

        /// <summary>Initializes a new instance of <see cref="NamedPipeListener{TMessage}" /> using the default pipe name.</summary>
        /// <remarks>The default pipe name is the full name of the type of the instance.</remarks>
        public NamedPipeListener()
            : this(DEFAULT_PIPENAME) { }

        /// <summary>The name of the named pipe that will be used to listen on.</summary>
        public String PipeName { get; private set; }

        /// <summary>Starts listening on the named pipe specified for the instance.</summary>
        internal void Start()
        {
            if (pipeServer == null) pipeServer = new NamedPipeServerStream(DEFAULT_PIPENAME, PipeDirection.In, 1, PipeTransmissionMode.Message, PipeOptions.Asynchronous);

            try { pipeServer.BeginWaitForConnection(new AsyncCallback(PipeConnectionCallback), null); }
            catch (Exception ex) { this.OnError(NamedPipeListenerErrorType.BeginWaitForConnection, ex); }
        }

        private void PipeConnectionCallback(IAsyncResult result)
        {
            try
            {
                pipeServer.EndWaitForConnection(result);
            }
            catch (Exception ex)
            {
                this.OnError(NamedPipeListenerErrorType.EndWaitForConnection, ex);
                return;
            }

            TMessage message;
            try
            {
                message = (TMessage)formatter.Deserialize(pipeServer);
            }
            catch (Exception ex)
            {
                this.OnError(NamedPipeListenerErrorType.DeserializeMessage, ex);
                return;
            }

            try
            {
                this.OnMessageReceived(new NamedPipeListenerMessageReceivedEventArgs<TMessage>(message));
            }
            catch (Exception ex)
            {
                this.OnError(NamedPipeListenerErrorType.NotifyMessageReceived, ex);
                return;
            }

            if (this.End())
            {
                this.Start();
            }
        }

        internal Boolean End()
        {
            try
            {
                pipeServer.Close();
                pipeServer.Dispose();
                pipeServer = null;

                return true;
            }
            catch (Exception ex)
            {
                this.OnError(NamedPipeListenerErrorType.CloseAndDisposePipe, ex);
                return false;
            }
        }

        private void OnMessageReceived(TMessage message)
        {
            this.OnMessageReceived(new NamedPipeListenerMessageReceivedEventArgs<TMessage>(message));
        }

        protected virtual void OnMessageReceived(NamedPipeListenerMessageReceivedEventArgs<TMessage> e)
        {
            if (this.MessageReceived != null)
            {
                this.MessageReceived(this, e);
            }
        }

        private void OnError(NamedPipeListenerErrorType errorType, Exception ex)
        {
            this.OnError(new NamedPipeListenerErrorEventArgs(errorType, ex));
        }

        protected virtual void OnError(NamedPipeListenerErrorEventArgs e)
        {
            if (this.Error != null)
            {
                this.Error(this, e);
            }
        }

        void IDisposable.Dispose()
        {
            if(pipeServer != null)
            {
                try { pipeServer.Disconnect(); }
                catch { }

                try { pipeServer.Close(); }
                catch { }

                try { pipeServer.Dispose(); }
                catch { }
            }
        }

        /// <summary>Sends the specified <paramref name="message" /> to the default named pipe for the message.</summary>        
        /// <param name="message">The message to send.</param>
        public static void SendMessage(TMessage message)
        {
            NamedPipeListener<TMessage>.SendMessage(DEFAULT_PIPENAME, message);
        }

        /// <summary>Sends the specified <paramref name="message" /> to the specified named pipe.</summary>
        /// <param name="pipeName">The name of the named pipe the message will be sent to.</param>
        /// <param name="message">The message to send.</param>
        public static void SendMessage(String pipeName, TMessage message)
        {
            using (var pipeClient = new NamedPipeClientStream(".", DEFAULT_PIPENAME, PipeDirection.Out, PipeOptions.None))
            {
                pipeClient.Connect();

                formatter.Serialize(pipeClient, message);
                pipeClient.Flush();

                pipeClient.WaitForPipeDrain();
                pipeClient.Close();
            }
        }
    }
}

Answer 2

我之前已經對此進行過研究 - 您可以使用內存映射文件，在本文中演示http://www.codeproject.com/KB/cs/singleinstanceapplication.aspx ，或者您可以做我做的事情（簡單的方法）並利用vb.net功能（特別是，允許​​您創建單實例應用程序並在當前運行的實例中調用方法，該方法傳遞命令行參數[因此您可以使用它來調用應用程序中的方法]） 。 我知道在C＃中使用VB類聽起來有點差，但這是最抽象和簡單的方法。 鏈接到相關的文章- http://www.codeproject.com/KB/cs/CSSIApp.aspx的最后一部分http://msdn.microsoft.com/en-us/magazine/cc163741.aspx