soheilkd / singleinstancecore Goto Github PK

Awesome library!

I'm trying to get it to work with WinForms.

This is my current attempt:

static class Program
{
    [STAThread]
    static void Main(string[] args)
    {
        var app = new TestApplication();

        var isFirstInstance = app.InitializeAsFirstInstance("Test");
        if (isFirstInstance)
        {
            try
            {
                app.Run();
            }
            finally
            {
                SingleInstance.Cleanup();
            }
        }
    }
}

class TestApplication : ISingleInstance
{
    public void Run()
    {
        Application.SetHighDpiMode(HighDpiMode.SystemAware);
        Application.EnableVisualStyles();
        Application.SetCompatibleTextRenderingDefault(false);
        Application.Run(new MainForm());
    }

    public void OnInstanceInvoked(string[] args)
    {
        MessageBox.Show("OnInstanceInvoked");
        throw new NotImplementedException();
    }
}

Observation:

• There is only one instance created
• OnInstanceInvoked is not invoked on any instance
• Application.Run(new MainForm()) blocks until the main form is closed
• In the second instance, InitializeAsFirstInstance returns false, as expected

What am I doing wrong?

If we get this to work, I'd like create a PR to put a WinForms sample in the README.

Hello! I am using this in something I plan to use the MIT License for, would you mind adding the same license to SingleInstanceCore?

Thanks in advance.

Hi,

I've come across a scenario where subsequent instances crash with the following error:

System.TimeoutException: Gave up waiting for read lock
   at TinyIpc.Synchronization.TinyReadWriteLock.AcquireReadLock() in /_/src/TinyIpc/Synchronization/TinyReadWriteLock.cs:line 130
   at TinyIpc.IO.TinyMemoryMappedFile.Read() in /_/src/TinyIpc/IO/TinyMemoryMappedFile.cs:line 158
   at TinyIpc.Messaging.TinyMessageBus..ctor(ITinyMemoryMappedFile memoryMappedFile, Boolean disposeFile, TimeSpan minMessageAge) in /_/src/TinyIpc/Messaging/TinyMessageBus.cs:line 111
   at TinyIpc.Messaging.TinyMessageBus..ctor(ITinyMemoryMappedFile memoryMappedFile, Boolean disposeFile) in /_/src/TinyIpc/Messaging/TinyMessageBus.cs:line 90
   at TinyIpc.Messaging.TinyMessageBus..ctor(String name) in /_/src/TinyIpc/Messaging/TinyMessageBus.cs:line 63
   at SingleInstanceCore.SingleInstance.SignalFirstInstance(String channelName, IList`1 commandLineArgs)
   at SingleInstanceCore.SingleInstance.InitializeAsFirstInstance[T](T instance, String uniqueName)

This happens when multiple files are selected and opened from Windows File Explorer, each file starting an instance of my application and then all these instances end up trying to signal the first instance at the same time. I've worked around this in my code by setting up a named Mutex that only allows one instance at a time calling InitializeAsFirstInstance:

using (var mutex = new Mutex(false, uniqueAppName))
{
    try { mutex.WaitOne(3000); } catch (AbandonedMutexException) { }
                
    try
    {
       if (!this.InitializeAsFirstInstance(uniqueAppName))
           Environment.Exit(0);
    }
    finally
    {
        mutex.ReleaseMutex();
    }
}

This works, but it would probably be better if SingleInstanceCore handled this internally, inside the SingleInstance.SignalFirstInstance method.

Thanks for making this library available!

Does this library also work with .NET 5/6?

Is it possible to use it with WinForms?

Thanks mate, this works like a charm.

Just a small typo, change:
bool isFirstInstance = SingleInstance.InitializeAsFirstInstance("soheilkd_EPlayerIPC"))
to:
bool isFirstInstance = SingleInstance.InitializeAsFirstInstance("soheilkd_EPlayerIPC");
in the README (change the ) to a ;)

We're having a problem where OnInstanceInvoked isn't getting triggered. I cloned the code and debugged it locally, and it seems like the message bus was being disposed of before it finished sending the command line arguments to the first instance. Adding a short Thread.Sleep() before calling Cleanup() solved the problem temporarily.

Our application pretty much matches the example code.

This problem occurred on 2.0, though I believe it was also present on 1.0 as we upgraded to try and see if it would fix the problem.

File SerializationExtensions.cs uses old methods and you get warnings if compiling in NET5.

Solution:

using System.Runtime.Serialization.Formatters.Binary;
using System.Text;
using System.Text.Json;
using System.Text.Json.Serialization;

namespace SingleInstanceCore
{
	//For inline serializing and deserializing
	internal static class SerializationExtensions
	{
		internal static byte[] Serialize<T>(this T obj)
		{
			return Encoding.UTF8.GetBytes(JsonSerializer.Serialize(obj, GetJsonSerializerOptions()));
		}

		internal static T Deserialize<T>(this byte[] data)
		{
			return JsonSerializer.Deserialize<T>(data, GetJsonSerializerOptions());
		}

		private static JsonSerializerOptions GetJsonSerializerOptions()
		{
			return new JsonSerializerOptions()
			{
				PropertyNamingPolicy = null,
				WriteIndented = true,
				AllowTrailingCommas = true,
				DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull,
			};
		}
	}
}

I used this code some years ago:

var processesCount = Process.GetProcesses().Count(p => p.ProcessName == Process.GetCurrentProcess().ProcessName);
if (processesCount > 1)
{
  Shutdown();
}

Does not it do the same as this library in general?