Single instance application C#

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1.00/5 (1 vote)

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I have a situation where my application on first establishes a connection to the DB and does some startup routine using a login assembly and then the main user interface (of another assembly) is presented to the user. Now there is another part of my main application that presents another user interface to the user but this also first instantiate the login assembly and then does the same thing.
What I am trying to achieve is that whatever application I launch that uses login assembly they all just use the running instance of login assembly and don't launch new instance of login assembly.

The login assembly is not large but all other applications when launched have to login to the system first and then they display the application windows. So imagine I launch App1 it will first get instance of login assembly do the login and then launch the App1 window. Then I launch App2 it does the same thing; first get instance of login assembly do the login and then launch the App1 window.

One thing I missed in mentioning is that the once login is successful it leave a logon information window open to make certain information always available to the user.

Hence you can imagine App1, App2, App3 etc all leaving one instance of log information window open.

Which is why the idea is for every App to check if there is a running instance of Logon information and if found use it else create a new one.

What I have tried:

Singleton pattern based login assembly but every calling application still gets a new instance of the login assmelby

Posted 17-Mar-16 6:04am

Member 10279542

Updated 25-Mar-16 4:11am

v2

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ZurdoDev 17-Mar-16 12:12pm

How can we help?

Sascha Lefèvre 17-Mar-16 12:22pm

Why would you want to do that? Is your login assembly that large that you need to conserve memory?

Member 10279542 18-Mar-16 2:52am

The login assembly is not large but all other applications when launched have to login to the system first and then they display the application windows. So imagine I launch App1 it will first get instance of login assembly do the login and then launch the App1 window. Then I launch App2 it does the same thing; first get instance of login assembly do the login and then launch the App1 window.

One thing I missed in mentioning is that the once login is successful it leave a logon information window open to make certain information always available to the user.

Hence you can imagine App1, App2, App3 etc all leaving one instance of log information window open.

Which is why the idea is for every App to check if there is a running instance of Logon information and if found use it else create a new one.

Sergey Alexandrovich Kryukov 25-Mar-16 0:43am

Will you take a look at my second answer (Solution 2)? This is a really interesting topic. I just prepared the code for an article, but provide a full preview source code. I think it's interesting enough (short description of the idea can be found in Solution 1.)
—SA

CHill60 17-Mar-16 13:16pm

Does this article help? Inter-Process Communication in .NET Using Named Pipes, Part 1[^]
or if both assemblies are in the same executable - Friend Assemblies (C# and Visual Basic)[^]

2 solutions

Solution 2

All right, here is my second answer, with more detail for you. I've done some work to generalize my solution I described earlier, to make it customizable and usable with all kinds of interactive applications.

In the meanwhile, you can see full preview source code, complete with UI demo. I hope everything is clear: S.A.Kryukov-SingleApplicationInstance.dotNet.src.zip (11.6 KB).

Later on, I'll write a formal article using this code. If you have some questions before I'm done, I'll try to answer.

[EDIT]

New updated solution is ready, in my new article: All Three Features of Single-Instance Applications at One Shot, .NET.

Importantly, this solution is different from what I temporarily published. In new version, I seriously took care about its portability. Now it should work correctly (via alternative CLR implementation, first of all, Mono) on non-Microsoft platforms, in particular, based on UNIX-like OS.

—SA

Posted 24-Mar-16 18:36pm

Sergey Alexandrovich Kryukov

Updated 2-Apr-16 19:54pm

v5

Comments

Maciej Los 25-Mar-16 2:38am

5+ for effort!

Sergey Alexandrovich Kryukov 25-Mar-16 2:48am

Thank you, Maciej.
—SA

[no name] 25-Mar-16 8:15am

I did not downloaded it, but I trust in you. So a 5 from my side.
Bruno

Sergey Alexandrovich Kryukov 25-Mar-16 9:52am

Thank you, Bruno.
—SA

[no name] 25-Mar-16 10:11am

It is sad that somebody voted again against you without giving a comment... I wish that CP changes the rules: If you downvote you have to give a comment... and as a consequence, the vote is known.
Bruno

Sergey Alexandrovich Kryukov 25-Mar-16 14:23pm

This is a complicated problem. A good number of people who are just fooling around here may not deserve a comment, or one comment from a previously down-voted person would be enough. But I would not mind the type of enforcement you suggested; it might evoke more responsible voting. I don't know... and don't care so much to stress on that. It's bad that some, as it seems to me, voted on the basis unrelated to real post quality...
—SA

Sergey Alexandrovich Kryukov 1-Apr-16 2:59am

Bruno,

I'm about to write an article on this topic, but first, the priority: today is April 1st.

I would like to invite you to read my new 1st of April article: Gravitational Internet.

And this is the previous on, updated: Some Programming Approaches to "Neuro-Linguistic Programming".

Hope you like it. :-)

—SA

Sergey Alexandrovich Kryukov 3-Apr-16 1:56am

Pay attention: new update to the solution is ready, this time as a fully-fledged article.
And the solution is seriously improved, see the update above, after [EDIT].

See also just published article of Free Pascal:
Single-Instance Applications Behavior, now for Free Pascal.

—SA

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Sergey Alexandrovich Kryukov · Accepted Answer · 2016-03-17T07:34:00

Solution 1

Too bad I don't have anything ready for publishing at the moment, but I have a very accomplished and lean single-instance system, which also passes command-line argument to an original instance, really guarantees uniqueness, and so on. Perhaps my short description can help you:

Enter multiple commands to only one process instance[^],
Custom Windows right-click command launching multiple instances[^].

If you have any questions, I'll gladly try to answer.

—SA

Posted 17-Mar-16 7:34am

Sergey Alexandrovich Kryukov

Updated 17-Mar-16 7:35am

v2

Comments

[no name] 17-Mar-16 19:09pm

Boah! a Little compensation :(

Sergey Alexandrovich Kryukov 17-Mar-16 19:19pm

Thank you, Bruno.
As you can see, someone follows all my posts methodically. It's getting funny.
—SA

Sergey Alexandrovich Kryukov 25-Mar-16 0:38am

By the way, please see my Solution 2. I finally created a separate utility suitable for publishing and uploaded my preview source code. Please see; I think it's interesting enough.

And I prepared the Free Pascal analog of it, which is much, much more compact than .NET version. As a Delphi developer, you might be interested. This is a topic for another article.

—SA

Maciej Los 18-Mar-16 18:22pm

5ed!

Sergey Alexandrovich Kryukov 18-Mar-16 18:25pm

Thank you, Maciej.
By the way, I just wrote a Free Pascal variant of the same thing, in just an hour or so, it turns out very compact, still dual-purpose (exiting on first instance check and passing command line). Would be good to publish, anyway, just needs time.
—SA

Maciej Los 18-Mar-16 18:29pm

Let me know when if finish. I would like to read it.

Sergey Alexandrovich Kryukov 18-Mar-16 18:50pm

What, in Free Pascal? Do you use it? I would highly recommend it, by some good reasons, but cannot say it's too easy...
—SA

Maciej Los 19-Mar-16 11:56am

No, i'm not using it, but i did use it in a past.

Sergey Alexandrovich Kryukov 19-Mar-16 19:32pm

Likewise.
But Free Pascal should give new life to it. They develop great cross-platfrom model. You can develop in a portable way (the things I'm doing right now is porting my old Windows-only VCL Delphi stuff to portable), and then you can compile the same thing on Windows, Linux, Android, Mac/iOS, as well as a lot of different things with many different processors. Yes, with GUI. The way of using a cross compilation (if one needs it) is also very interesting: running the IDE, you can ask it to build an alternative Lazarus, say, in different directory. You specify the new platform and target processor detail, and it build it for you.

There is a lot of inconvenience and missing functionality. Take Regex, which I badly need. .NET Regex is one of the most advanced ones from what you can get, but with Pascal, there is only Sorokin's engine, badly insufficient in features and not even fully consistent. And some features exceeds .NET, especially in terms of portable code. For example, on .NET there is no managed SendInput, so, to create a virtual keyboard or key macro player, you have to P/Invoke it, but on Free Pascal one guy managed to provide very simplified cross-platform version (with separate implementations on each platform of the many which are linked in during build). And do on...

—SA

Maciej Los 20-Mar-16 6:21am

Very interesting... I'm wondering how do you find a time for improving your knowledge? Seems you're never sleeping ;)
Have a nice day, Sergey!

Sergey Alexandrovich Kryukov 25-Mar-16 0:39am

By the way, I'm keeping my promise.

Please see my Solution 2. This is not an article yet, but the code is ready. I finally created a separate utility suitable for publishing and uploaded my preview source code. Please see; I think it's interesting enough.

I actually completed my port to Free Pascal (Lazarus) and hope it's no multiplatform. A part of this code is Free Pascal version of the same single-instance application facility, based on IPC included in Free Pascal product. In Free Pascal, it's so compact, compared to .NET! It would be good to publish an article, too.

—SA

Maciej Los 25-Mar-16 2:37am

Well... Thank you very much, Sergey for keeping the promise. I'll look at the code...

Sergey Alexandrovich Kryukov 25-Mar-16 2:49am

You are very welcome. The code is updated: simplified/improved..
—SA

CPallini 25-Mar-16 3:47am

My 5.

Sergey Alexandrovich Kryukov 25-Mar-16 9:52am

Thank you, Carlo.
—SA