C# pass the paramters to runnning process.

Question

Prevent the same process from running.
And when the process is running,
I want to pass parameters to the running process.

But I don't know how.

   static void Main(string[] args)  
    {  
        Process[] processes = null;  
        string strCurrentProcess = Process.GetCurrentProcess().ProcessName.ToUpper();  
        processes = Process.GetProcessesByName(strCurrentProcess);  

        if (processes.Length > 1)  
        {  
            if (args.Length > 1)  
            {  
                //Pss Paramater to running process  
                return;  
            }  
            else  
            {  
                return;  
            }  
        }  
        else  
        {  
            if (args.Length > 1)  
            {  
                Application.Run(new FrmMain(args));  
            }  
            else  
            {  
                Application.Run(new FrmMain());  
            }  
        }  
    }

Answer 1

@LWY , Welcome to Microsoft Q&A, We could use command line to pass the parameters to running process.

First, I make the following code to check if the parameters' count is more than 1.

Code example:

 static void Main(string[] args)  
        {  
            Application.EnableVisualStyles();  
            Application.SetCompatibleTextRenderingDefault(false);  
            if (args.Length> 1)  
            {  

                Application.Run(new Form1());  
            }  
            else  
            {  
                Application.Run(new Form2());  
            }  
        }  

Second, Please try the following command to pass the parameters to winform project:

CD E:\WindowsFormsApp1\bin\Debug (Your project path)  
  
E:\WindowsFormsApp1\bin\Debug>WindowsFormsApp1.exe test1 test2  
  
E:\WindowsFormsApp1\bin\Debug>WindowsFormsApp1.exe test1  

Result1:

Result2:

Hope my answer could help you.

Best Regards,
Jack

---

If the answer is the right solution, please click "Accept Answer" and upvote it.If you have extra questions about this answer, please click "Comment".
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

Answer 2

You cannot prevent the same application from running. What you can do is instead of creating a new form in your new process, look for an existing form and if found, send the command line argument to the existing form before exiting.

Your existing form then need to process that notification (e.g. open the file passed in the arguments and restored from minimized if necessary).

There is an implementation in WindowsFormsApplicationBase (requires referencing Microsoft.VisualBasic.Forms.dll). For an example check https://www.hanselman.com/blog/the-weekly-source-code-31-single-instance-winforms-and-microsoftvisualbasicdll. If you are interested in writing your own, you can use a mutex and a named pipe (https://www.autoitconsulting.com/site/development/single-instance-winform-app-csharp-mutex-named-pipes/).