communicate between the instances of an application

Question

I have a winforms Application,

On Close button click, I am hiding that application into system tray just like how skype works..

If the application is instantiated again and if an instance of that application is already running, then I want to bring the already running application(may be in tray) to front and exit the new one..

What I thought of doing is something like this in the Main mathod using the WCF

Process currentProcess = Process.GetCurrentProcess();
Process[] processes = Process.GetProcesses();
bool running = false;
foreach (var process in processes)
{
    if (process.ProcessName == currentProcess.ProcessName 
        && process.Id != currentProcess.Id)
    {
        running = true;
    }
}

if (running)
{

    ChannelFactory<IService1> pipeFactory = new 
        ChannelFactory<IService1>(new NetNamedPipeBinding(),
                    new EndpointAddress("net.pipe://localhost/PipeActivate"));

    IService1 pipeProxy = pipeFactory.CreateChannel();
    pipeProxy.ActivateThisWindow();

    Application.Exit();
}
else
{

    using (ServiceHost host = new 
        ServiceHost(typeof(Form1), 
                new Uri[] { new Uri("net.pipe://localhost") }))
    {

        host.AddServiceEndpoint(typeof(IService1), 
                        new NetNamedPipeBinding(), "PipeActivate");

        host.Open();

        Application.EnableVisualStyles();
        Application.SetCompatibleTextRenderingDefault(false);
        Application.Run(new Form1());

        host.Close();
    }
}

where

void IService1.ActivateThisWindow()
    {
        this.Show();
        if (this.WindowState != FormWindowState.Normal)
            this.WindowState = FormWindowState.Normal;
        this.Activate();
    }

now the problem is, its bringing the running instance to front but as the new instance exits, its going to its previous state.

What is the problem? How can I solve this?

what other ways I can use to achieve this requirement?

Why are you trying to deal with multiple instances. The Skype process doesn't end when it gets sent to the system bar. — Security Hound, Jun 26 '12 at 11:51

score 2 · Accepted Answer · edited May 23 '17 at 12:12

2

While this is a very novel approach, it is kind of overkill. There is an easier and more widely used way to handle this problem as seen here.

What is the correct way to create a single-instance application?

Speaking from personal experience, I used this resource for all of my single instance apps, and it works like a charm.

edited May 23 '17 at 12:12

Community

1
1

answered Jun 26 '12 at 11:55

A.R.

15,405
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Brijesh Mishra · Answer 2 · 2012-06-26T12:51:46.387

1

I presume you have implemented IService1.ActivateThisWindow in Form 1 class, So this behaviour is because new instance of form1 is getting created for each request on host app and is destroyed when request ends. To solve the problem factor out IService1.ActivateThisWindow in seperate class so form1 is not host object and make form1 singleton.

edited Jun 26 '12 at 12:51

answered Jun 26 '12 at 12:13

Brijesh Mishra

2,738
1
21
36

here in already running process new instance of form1 is getting created when you send request from a new process. This is due to instancing in wcf, a new instance of host object is created per request/session. You can verify this by logging process id in constuctor of form1 – Brijesh Mishra Jun 26 '12 at 12:50

communicate between the instances of an application

2 Answers2