How do I communicate from one c# project to another c# project

Question

From my first project, I check a checkmark, then this line of code runs:

if (checkbox1.Checked == true)
{
  File.WriteAllText("C:\\True.txt", "fshfgyusfusd");
}

Then from my second project, when the form loads, I wanted it to sync the checkmark, so here is my code:

if (File.Exists("C:\\True.txt"))
{
 checkbox1.Checked = true;
}

Is there another easier way to do this, or this is the easier way, I basically want if the first projects checkmark is checked, then the second form loads, and only check the checkmark when the first form checkmark is checked

Please provide a [Minimal, Reproducible Example](https://stackoverflow.com/help/minimal-reproducible-example) so that others can actually see the context of your issue and **help them help you.** — pensum, Nov 08 '19 at 02:50
There are a lot of ways but what I would do is setup both projects to use a single database (for checking). — Jerdine Sabio, Nov 08 '19 at 02:50
Does this answer your question? [Object Sharing between Applications?](https://stackoverflow.com/questions/28335037/object-sharing-between-applications) — , Nov 08 '19 at 03:16
That's actually the easiest. But also the worst, you should consider WCF or .NET remoting or Pipes. — Javier Silva Ortíz, Nov 08 '19 at 03:58

score 1 · Answer 1 · answered Nov 08 '19 at 02:51

You do have to have some way to communicate.

If your two programs are going to be running at the same time, you can use a socket, or possibly a mutex. If they are not running at the same time, you will have to save stuff to a file, or a database. Possibly your first app could notify a third party -- most likely a webservice -- and the second app could inquire of the webservice whether it happened.

But for asynchronous communication like you've described, files are probably the easiest.

A few suggestions:

Your applications should not write to the root of your C: drive. They should probably stick to either your temporary folder, or a folder under your user profile (C:\Users\CNTowerGUN), or a folder dedicated to the program under C:\ProgramData. Each of the apps should check if the folder exists before proceeding.
It may be more useful to write the current time than to write a random string. This will assist if you are debugging. Likewise the second app may want to actually read from the file to check its contents.
The app doing the writing should be on guard for the possibility that the file cannot be written, due to insufficient permission or the file being in use.

How do I communicate from one c# project to another c# project

1 Answers1