Your program runs only once

I will introduce two mainstream methods. Method 1: Use mutex for 1. first, add the following namespace: using system. threading; 2. modify the main function of the system as follows: bool bcreatednew; // create a new mutex using specific mutex name mutex M = new mutex (false, "myuniquename", out bcreatednew ); if (bcreatednew) application. run (New yourformname (); if it is encoded above, note that it is not too simple to name mutex, to prevent repeated mutex with other programs and thus fail to achieve the expected results. Method 2: Use process for 1. first, add the following namespace: using system. diagnostics; using system. reflection; 2. add the following function: 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 in processes) {// ignore the current process if (process. I D! = 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;} 3. modify the system main function as follows: If (runninginstance () = NULL) application. run (New yourformname (); for example, you can encode the code above. Note that when judging Optional. If only one program exists in the file system, the above method is acceptable; otherwise, do not delete this part of code. Compared with the two methods, in terms of efficiency and simplicity, the former method is the best and I like it. The latter method is slow, secondly, we use processname to search for the process in the system. It is possible that the process is not what I want. Although the file directory is added to the end to judge the process, but it contains potential problems (as mentioned above ). However, the first method also has a defect, that is, the scalability operation is inconvenient. For example, if the program runs only once, it is popped up and displayed to the beginning. The latter method is advantageous.