How to check if another instance of the application is running [duplicate]

Answer 1

Here are some good sample applications. Below is one possible way.

public static Process RunningInstance() 
{ 
    Process current = Process.GetCurrentProcess(); 
    Process[] processes = Process.GetProcessesByName (current.ProcessName); 

    //Loop through the running processes in with the same name 
    foreach (Process process in processes) 
    { 
        //Ignore the current process 
        if (process.Id != current.Id) 
        { 
            //Make sure that the process is running from the exe file. 
            if (Assembly.GetExecutingAssembly().Location.
                 Replace("/", "\\") == current.MainModule.FileName) 

            {  
                //Return the other process instance.  
                return process; 

            }  
        }  
    } 
    //No other instance was found, return null.  
    return null;  
}


if (MainForm.RunningInstance() != null)
{
    MessageBox.Show("Duplicate Instance");
    //TODO:
    //Your application logic for duplicate 
    //instances would go here.
}

Many other possible ways. See the examples for alternatives.

First one.

Second One.

Third One

EDIT 1: Just saw your comment that you have got a console application. That is discussed in the second sample.