Restarting current process C# - c#

I have an app that has some installer inside I want to reload everything associated to the app therefor I want to restart the process. I've searched and saw the Application.Restart() and it's drawbacks and wondered what's the best way to do what I need - closing the process and restarting it. or if there's any better way to reinitialize all objects.

I would start a new instance and then exit the current one:
private void Restart()
{
Process.Start(Application.ExecutablePath);
//some time to start the new instance.
Thread.Sleep(2000);
Environment.Exit(-1);//Force termination of the current process.
}
private static void Main()
{
//wait because we maybe here becuase of the system is restarted so give it some time to clear the old instance first
Thread.Sleep(5000);
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
Application.Run(...
}
Edit: However you should also consider adding some sort of mutex to allow only one instance of the application to run at time, Like:
private const string OneInstanceMutexName = #"Global\MyUniqueName";
private static void Main()
{
Thread.Sleep(5000);
bool firstInstance = false;
using (System.Threading.Mutex _oneInstanceMutex = new System.Threading.Mutex(true, OneInstanceMutexName, out firstInstance))
{
if (firstInstance)
{
//....
}
}
}

In my WPF application (single instance by a mutex), I use Process.Start with a ProcessStartInfo, which send a timed cmd command to restart the app:
ProcessStartInfo Info = new ProcessStartInfo();
Info.Arguments = "/C ping 127.0.0.1 -n 2 && \"" + Application.GetCurrentProcess()+ "\"";
Info.WindowStyle = ProcessWindowStyle.Hidden;
Info.CreateNoWindow = true;
Info.FileName = "cmd.exe";
Process.Start(Info);
ShellView.Close();
The command is sent to the OS, the ping pauses the script for 2-3 seconds, by which time the application has exited from ShellView.Close(), then the next command after the ping starts it again.
Note: The \" puts quotes around the path, incase it has spaces, which cmd can't process without quotes.
(My code references this answer)

I think starting a new process and closing the existing process is the best way. In this way you have the ability to set some application state for the existing process in between starting and closing processes.
This thread discusses why Application.Restart() may not work in some cases.
System.Diagnostics.Process.Start(Application.ResourceAssembly.Location);
// Set any state that is required to close your current process.
Application.Current.Shutdown();
Or
System.Diagnostics.Process.Start(Application.ExecutablePath);
// Set any state that is required to close your current process.
Application.Exit();

Related

Running commands in CMD as administrator

Rules that i need to hold on to are the following:
run command prompt command as administrator
change directory (path is always the same)
run command net start something
Any thoughts on how can i do this programatically using C# ?
Just for the record i am running console application built in .net 4.0
I am using this function
private static void commandtorun(string commandexecuted)
{
string currentstatus;
ProcessStartInfo startInfo = new ProcessStartInfo();
Process myprocess = new Process();
try
{
startInfo.FileName = "cmd"; //
startInfo.RedirectStandardInput = true;
startInfo.RedirectStandardOutput = true;
startInfo.UseShellExecute = false; //'required to redirect
//startInfo.CreateNoWindow = true; // '<---- creates no window, obviously
myprocess.StartInfo = startInfo; //
myprocess.Start(); //
System.IO.StreamReader SR;
System.IO.StreamWriter SW;
Thread.Sleep(200);
SR = myprocess.StandardOutput;
SW = myprocess.StandardInput;
SW.WriteLine(commandexecuted); // 'the command you wish to run.....
SW.WriteLine("exit"); // 'exits command prompt window
Thread.Sleep(200);
currentstatus = SR.ReadToEnd();
SW.Close();
SR.Close();
}
catch (Exception e)
{
Console.WriteLine("{0} Exception caught.", e);
Console.ReadLine();
}
// throw new NotImplementedException();
}
and i get access is denied when i call the function using this command:
commandtorun(#"cd c:\Program Files (x86)\folder1\folder2"); // change the folder because cmd always runs on different path
commandtorun("net start something"); run the COMMAND
I tried to run both commands in one statement but got the same error.
There are lots of problems here.
You want to run the other process elevated, but your code does not take steps to make that happen. In order to do that you need to invoke your process with the runas verb, and UseShellExecute set to true. But you also want to re-direct which is why you set UseShellExecute to false.
I see no compelling reason to redirect, so I think you can use true for UseShellExecute. You are pumping an exit command into cmd.exe to terminate the process. You don't need to do that. Simply pass cmd.exe the /c argument and the process will close when it is done.
These changes will allow you to remove those calls to Sleep(). Any time you call Sleep() you should ask yourself why you are doing it and if it can be avoided. Very few problems have Sleep() as the optimum solution.
You are trying to specify the working directory by executing cd. That again is the wrong way to do it. You can specify the working directory in the ProcessStartInfo object. That's how you should do it.
Your design has you executing each command in a separate process. That's a really poor way to go. You want to execute all the commands one after the other in a single instance of cmd.exe. Put the commands into a .bat or .cmd file and get cmd.exe to process that.
Imagine if you carried on processing each command as a separate process. How would the second process remember the working directory change that you made? Would you really want your user to see a UAC dialog for each separate command?
Having said all of that though, you are going about this the wrong way. You are just trying to start a service. Yes, you do that with net start when you are working in the command line. But from a program you use the service API to start a service. In other words I believe that you should throw away all of this code and call the service API.

How to wait until MSTSC.exe exits

I have created a management application that also allows to quickly access a remote desktop session to remote machines. I need to wait until the process ends, so I can close the VPN connection to the remote server. Everything works fine, except waiting for the process to end.
The following code is being used to start the MSTSC process and wait until it ends:
var process = new Process
{
StartInfo = new ProcessStartInfo("mstsc.exe"),
EnableRaisingEvents = true
};
process.Exited += (o, e) => Console.WriteLine("Process stopped.");
process.Start();
Console.ReadLine();
The Exited event is raised almost immediately after the program starts. When I replace mstsc.exe with notepad.exe everything works as expected. I thought that MSTSC might fork itself and abort the initial process.
But it is possible to wait for MSTSC to end using the following command (from the commandline):
start /wait mstsc.exe
This command doesn't return until I exit the remote desktop session. Given that information I replaced my code with this:
var process = new Process
{
StartInfo = new ProcessStartInfo("cmd.exe"),
Arguments = "/c start /wait mstsc.exe",
EnableRaisingEvents = true
};
process.Exited += (o, e) => Console.WriteLine("Process stopped.");
process.Start();
Console.ReadLine();
This would run CMD.exe and it will issue the start /wait mstsc.exe command. If that ends, the CMD process ends as well and I'm fine (with a nasty workaround, but okay). Unfortunately, this doesn't happen. The CMD process terminates immediately. Somebody knows what I am doing wrong?
process.WaitForExit();
Won't work because mstsc on start opens new copy of itself and closes original.
process.WaitForExit();
process = Process.GetProcessesByName(process.ProcessName).First();
process.WaitForExit();
Will work but it's awful workaround.
Update 1:
It seems that mstsc closes original process but NOT it's output stream!
So you can wait for process StandardOutput to close.
var process = new Process
{
StartInfo = new ProcessStartInfo("mstsc.exe") { UseShellExecute = false, RedirectStandardOutput = true }
};
process.Start();
process.StandardOutput.ReadToEnd(); //This will wait for stream to close.
Or if you don't want to block current thread:
var process = new Process
{
StartInfo = new ProcessStartInfo("mstsc.exe") { UseShellExecute = false, RedirectStandardOutput = true }
};
process.Start();
var outputResultPromise = process.StandardOutput.ReadToEndAsync();
outputResultPromise.ContinueWith(o=> Console.WriteLine("Stream closed"));
Console.ReadLine();
Here is the link at MSDN about starting mstsc,
It might be answer to your problem with mstsc closing immediately after running (raising Exited event). Try changing in Visual Studio target platform to AnyCPU.
Let's say your machine is 64bit Windows, your app is 32bit. The app runs 32bit mstsc. 32bit mstsc detects that Windows is 64bit, tries to close itself and run 64bit mstsc (Exited event is raised at that moment even though mstsc starts GUI window).
Changing target platform solved my issue.
There are multiple MSTSC processes running, so it's difficult to wait for one. What I don't understand is that CMD.EXE can do it when I use the start /wait command.
this worked with me:
process.Start();
Thread.Sleep(2000);
while(getNumProcesses() > 0)
process.WaitForExit();
private static int getNumProcesses()
{
Process[] myProcesses = Process.GetProcessesByName("mstsc");
return myProcesses.Length;
}
You cannot wait for mstsc.exe process. Say exactly, you cannot simply wait for end of remote desktop. When I observed mstsc.exe process by Process Monitor, mstsc passed his work to svchost, mstsc.exe ended, but remote desktop was still run.
But I wrote script for remoting application.
Script remoteCmd.cmd starts remoteApplication, remote machine creates a temp file ( \\tsclient\c..\temp\xxx) and remoteCmd.cmd waits until temp file exists.
See
https://github.com/turzik/WindowsScripts/tree/master/remoteApp
You need to call WaitForExit() after you call Start():
process.Start();
process.WaitForExit();
This overload causes the current thread to wait indefinitely to wait until the process exits. There's also an overload that allows you to specify the number of milliseconds you'd like to wait.

Restart application with Kill process id [duplicate]

Developing a C# .NET 2.0 WinForm Application. Need the application to close and restart itself.
Application.Restart();
The above method has proven to be unreliable.
What is a better way to restart the application?
A much simpler approach that worked for me is:
Application.Restart();
Environment.Exit(0);
This preserves the command-line arguments and works despite event handlers that would normally prevent the application from closing.
The Restart() call tries to exit, starts a new instance anyway and returns. The Exit() call then terminates the process without giving any event handlers a chance to run. There is a very brief period in which both processes are running, which is not a problem in my case, but maybe in other cases.
The exit code 0 in Environment.Exit(0); specifies a clean shutdown. You can also exit with 1 to specify an error occurred.
If you are in main app form try to use
System.Diagnostics.Process.Start( Application.ExecutablePath); // to start new instance of application
this.Close(); //to turn off current app
Unfortunately you can't use Process.Start() to start an instance of the currently running process. According to the Process.Start() docs:
"If the process is already running, no additional process resource is started..."
This technique will work fine under the VS debugger (because VS does some kind of magic that causes Process.Start to think the process is not already running), but will fail when not run under the debugger. (Note that this may be OS-specific - I seem to remember that in some of my testing, it worked on either XP or Vista, but I may just be remembering running it under the debugger.)
This technique is exactly the one used by the last programmer on the project on which I'm currently working, and I've been trying to find a workaround for this for quite some time. So far, I've only found one solution, and it just feels dirty and kludgy to me: start a 2nd application, that waits in the background for the first application to terminate, then re-launches the 1st application. I'm sure it would work, but, yuck.
Edit: Using a 2nd application works. All I did in the second app was:
static void RestartApp(int pid, string applicationName )
{
// Wait for the process to terminate
Process process = null;
try
{
process = Process.GetProcessById(pid);
process.WaitForExit(1000);
}
catch (ArgumentException ex)
{
// ArgumentException to indicate that the
// process doesn't exist? LAME!!
}
Process.Start(applicationName, "");
}
(This is a very simplified example. The real code has lots of sanity checking, error handling, etc)
I might be late to the party but here is my simple solution and it works like a charm with every application I have:
try
{
//run the program again and close this one
Process.Start(Application.StartupPath + "\\blabla.exe");
//or you can use Application.ExecutablePath
//close this one
Process.GetCurrentProcess().Kill();
}
catch
{ }
I had the same exact problem and I too had a requirement to prevent duplicate instances - I propose an alternative solution to the one HiredMind is proposing (which will work fine).
What I am doing is starting the new process with the processId of the old process (the one that triggers the restart) as a cmd line argument:
// Shut down the current app instance.
Application.Exit();
// Restart the app passing "/restart [processId]" as cmd line args
Process.Start(Application.ExecutablePath, "/restart" + Process.GetCurrentProcess().Id);
Then when the new app starts I first parse the cm line args and check if the restart flag is there with a processId, then wait for that process to Exit:
if (_isRestart)
{
try
{
// get old process and wait UP TO 5 secs then give up!
Process oldProcess = Process.GetProcessById(_restartProcessId);
oldProcess.WaitForExit(5000);
}
catch (Exception ex)
{
// the process did not exist - probably already closed!
//TODO: --> LOG
}
}
I am obviously not showing all the safety checks that I have in place etc.
Even if not ideal - I find this a valid alternative so that you don't have to have in place a separate app just to handle restart.
Start/Exit Method
// Get the parameters/arguments passed to program if any
string arguments = string.Empty;
string[] args = Environment.GetCommandLineArgs();
for (int i = 1; i < args.Length; i++) // args[0] is always exe path/filename
arguments += args[i] + " ";
// Restart current application, with same arguments/parameters
Application.Exit();
System.Diagnostics.Process.Start(Application.ExecutablePath, arguments);
This seems to work better than Application.Restart();
Not sure how this handles if your program protects against multiple instance. My guess is you would be better off launching a second .exe which pauses and then starts your main application for you.
It's simple, you just need to call the Application.Restart() method, this will invoke your application to be restarted. You must also exit from the local environment with an error code:
Application.Restart();
Environment.Exit(int errorcode);
You can create an enumeration of error codes so that you application will exit efficeintly.
Another method is to just exit from the application and start the process using the executable path:
Application.Exit();
System.Diagnostics.Process.Start(Application.ExecutablePath);
Try this code:
bool appNotRestarted = true;
This code must also be in the function:
if (appNotRestarted == true) {
appNotRestarted = false;
Application.Restart();
Application.ExitThread();
}
I figured an another solution out, perhaps anyone can use it, too.
string batchContent = "/c \"#ECHO OFF & timeout /t 6 > nul & start \"\" \"$[APPPATH]$\" & exit\"";
batchContent = batchContent.Replace("$[APPPATH]$", Application.ExecutablePath);
Process.Start("cmd", batchContent);
Application.Exit();
Code is simplified so take care of Exceptions and stuff ;)
I fear that restarting the entire application using Process is approaching your problem in the wrong way.
An easier way is to modify the Program.cs file to restart:
static bool restart = true; // A variable that is accessible from program
static int restartCount = 0; // Count the number of restarts
static int maxRestarts = 3; // Maximum restarts before quitting the program
/// <summary>
/// The main entry point for the application.
/// </summary>
[STAThread]
static void Main()
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
while (restart && restartCount < maxRestarts)
{
restart = false; // if you like.. the program can set it to true again
restartCount++; // mark another restart,
// if you want to limit the number of restarts
// this is useful if your program is crashing on
// startup and cannot close normally as it will avoid
// a potential infinite loop
try {
Application.Run(new YourMainForm());
}
catch { // Application has crashed
restart = true;
}
}
}
You are forgetting the command-line options/parameters that were passed in to your currently running instance. If you don't pass those in, you are not doing a real restart. Set the Process.StartInfo with a clone of your process' parameters, then do a start.
For example, if your process was started as myexe -f -nosplash myfile.txt, your method would only execute myexe without all those flags and parameters.
I wanted the new application start up after the old one shuts down.
Using process.WaitForExit() to wait for your own process to shutdown makes no sense. It will always time out.
So, my approach is to use Application.Exit() then wait, but allow events to be processed, for a period of time. Then start a new application with the same arguments as the old.
static void restartApp() {
string commandLineArgs = getCommandLineArgs();
string exePath = Application.ExecutablePath;
try {
Application.Exit();
wait_allowingEvents( 1000 );
} catch( ArgumentException ex ) {
throw;
}
Process.Start( exePath, commandLineArgs );
}
static string getCommandLineArgs() {
Queue<string> args = new Queue<string>( Environment.GetCommandLineArgs() );
args.Dequeue(); // args[0] is always exe path/filename
return string.Join( " ", args.ToArray() );
}
static void wait_allowingEvents( int durationMS ) {
DateTime start = DateTime.Now;
do {
Application.DoEvents();
} while( start.Subtract( DateTime.Now ).TotalMilliseconds > durationMS );
}
You could also use Restarter.
Restarter is an application that automatically monitor and restarts crashed or hung programs and applications. It was originally developed to monitor and restart game servers, but it will do the job for any console or form based program or application
public static void appReloader()
{
//Start a new instance of the current program
Process.Start(Application.ExecutablePath);
//close the current application process
Process.GetCurrentProcess().Kill();
}
Application.ExecutablePath returns your aplication .exe file path
Please follow the order of calls. You might want to place it in a try-catch clause.
The problem of using Application.Restart() is, that it starts a new process but the "old" one is still remaining. Therefor I decided to Kill the old process by using the following code snippet:
if(Condition){
Application.Restart();
Process.GetCurrentProcess().Kill();
}
And it works proper good. In my case MATLAB and a C# Application are sharing the same SQLite database. If MATLAB is using the database, the Form-App should restart (+Countdown) again, until MATLAB reset its busy bit in the database. (Just for side information)
How about create a bat file, run the batch file before closing, and then close the current instance.
The batch file does this:
wait in a loop to check whether the process has exited.
start the process.
Here's my 2 cents:
The sequence Start New Instance->Close Current Instance should work even for the applications that don't allow running multiple copies simultaneously as in this case the new instance may be passed a command-line argument which will indicate that there is a restart in progress so checking for other instances running will not be necessary. Waiting for the first instance to actually finish my be implemented too if it's absolutely imperative that no two intstances are running in parallel.
Application.Restart();
Environment.Exit(0);
I had a similar problem, but mine was related to unmanageable memory leak that I couldn't find on an app that has to run 24/7. With the customer I agreed that safe time to restart the app was 03:00AM if the memory consumption was over the defined value.
I tried Application.Restart, but since it seems to use some mechanism that starts new instance while it is already running, I went for another scheme. I used the trick that file system handles persist until process that created them dies. So, from The Application, i dropped the file to the disk, and didn't Dispose() the handle. I used the file to send 'myself' executable and starting directory also (to add flexibility).
Code:
_restartInProgress = true;
string dropFilename = Path.Combine(Application.StartupPath, "restart.dat");
StreamWriter sw = new StreamWriter(new FileStream(dropFilename, FileMode.Create, FileAccess.ReadWrite, FileShare.ReadWrite));
sw.WriteLine(Application.ExecutablePath);
sw.WriteLine(Application.StartupPath);
sw.Flush();
Process.Start(new ProcessStartInfo
{
FileName = Path.Combine(Application.StartupPath, "VideoPhill.Restarter.exe"),
WorkingDirectory = Application.StartupPath,
Arguments = string.Format("\"{0}\"", dropFilename)
});
Close();
Close() at the end would initiate app shutdown, and file handle I used for StreamWriter here would be held open until process really dies. Then...
Restarter.exe comes into action. It TRIES to read the file in exclusive mode, preventing it to gain access until main app wasn't dead, then starts main app, deletes the file and exists. I guess that it can't be simpler:
static void Main(string[] args)
{
string filename = args[0];
DateTime start = DateTime.Now;
bool done = false;
while ((DateTime.Now - start).TotalSeconds < 30 && !done)
{
try
{
StreamReader sr = new StreamReader(new FileStream(filename, FileMode.Open, FileAccess.ReadWrite, FileShare.ReadWrite));
string[] runData = new string[2];
runData[0] = sr.ReadLine();
runData[1] = sr.ReadLine();
Thread.Sleep(1000);
Process.Start(new ProcessStartInfo { FileName = runData[0], WorkingDirectory = runData[1] });
sr.Dispose();
File.Delete(filename);
done = true;
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
Thread.Sleep(1000);
}
}
I use the following and it does exactly what you are looking for:
ApplicationDeployment ad = ApplicationDeployment.CurrentDeployment;
UpdateCheckInfo info = null;
info = ad.CheckForDetailedUpdate();
if (info.IsUpdateRequired)
{
ad.UpdateAsync(); // I like the update dialog
MessageBox.Show("Application was upgraded and will now restart.");
Environment.Exit(0);
}
for using As logout you need to terminate all app from Ram Cache
so close The Application first and then Rerun it
//on clicking Logout Button
foreach(Form frm in Application.OpenForms.Cast<Form>().ToList())
{
frm.Close();
}
System.Diagnostics.Process.Start(Application.ExecutablePath);
You could enclose your code inside a function and when restart is needed you can just call the function.
Take for instance an application that:
While application is not registered; (upon start) the application should prompt the user to register the application and create a login account.
Once registration is submitted and login credentials are created; the application should restart, check for registration and prompt the user to login with the inserted credentials (so the user can access to all the application features).
Problem:
By building and launching the application from Visual Studio; any of the 4 alternatives bellow will fail to accomplish the tasks required.
/*
* Note(s):
* Take into consideration that the lines bellow don't represent a code block.
* They are just a representation of possibilities,
* that can be used to restart the application.
*/
Application.Restart();
Application.Exit();
Environment.Exit(int errorCode);
Process.GetCurrentProcess().Kill();
What happens is: After creating the Registration, Login and calling Application.Restart(); the application will (strangely) reopen the Registration Form and skip data in a Database (even though the resource is set to "Copy if Newer").
Solution:
Batch Building the application was (for me) a proof that any of the lines above were actually working as expected.
Just not when building and running the application with Visual Studio.
In first place I'd try batch building the application; run it outside Visual Studio and check if Application.Restart() actually works as expected.
Also Check further Info regarding this thread subject:
How do I restart my C# WinForm Application?
I've found a new way that's pretty convenient and has quite a few upsides.
There's never more than one instance running.
Command line args are persisted.
No exit events are raised from the application.
No process handles are broken.
I had a third party application managing my application with Process.Start and using Exit event to reload the application. Many of these solutions would break this implementation which is how I ended up on the following solution.
public static CancellationTokenSource _restartTokenSource;
/// <summary>
/// The main entry point for the application.
/// </summary>
[STAThread]
static void Main(string[] args)
{
// To customize application configuration such as set high DPI settings or default font,
// see https://aka.ms/applicationconfiguration.
ApplicationConfiguration.Initialize();
while (_restartTokenSource == null || _restartTokenSource.IsCancellationRequested)
{
_restartTokenSource = new System.Threading.CancellationTokenSource();
_restartTokenSource.Token.Register(() =>
{
foreach (Form form in Application.OpenForms)
form.Close();
});
Application.Run(new FlashMain(args));
}
}
Since Application.Run blocks until all forms in the application are closed I put this portion of the initialization into a loop that only executes when a CancellationTokenSource is null (the first run) or IsCancellationRequested is true (restart requested).
I register an event on the CancellationTokenSource that closes all forms in the application when .Cancel() is called, therefore unblocking Application.Run and restarting the loop.
Call Program._restartTokenSource.Cancel(); anywhere in the application to restart it.
P.S. This also works great for injecting into a BlazorWebView to restart the application from .NET Core.

Avoid locking service if process crashes / hangs

I am currently developing a windows service which implements fileSystemWatcher. Videos are uploaded into a folder at which point the filewatcher fires the created event as below to convert the video.
private void fileSystemWatcher_Created(object sender, System.IO.FileSystemEventArgs e)
{
if (ConvertVideo(e.FullPath, e.Name))
{
WriteToEventLog(String.Format("Successfully converted video - {0}", e.FullPath), EventLogEntryType.Information);
}
}
Within ConvertVideo a new process is created but I have run into issues where the process crashes / hangs / disappears and it appears the main thread is then locked as its waiting for WaitForExit() which effectively crashes the service as no other videos can then be converted. How could I avoid locking the entire service if the process dies?
private bool ConvertVideo(string SourcePath, string Filename)
{
try
{
// Create new process
ProcessStartInfo startInfo = new ProcessStartInfo();
startInfo.CreateNoWindow = false;
startInfo.UseShellExecute = false;
startInfo.FileName = "C:\Handbrake\HandBrakeCLI.exe";
startInfo.WindowStyle = ProcessWindowStyle.Hidden;
startInfo.Arguments = GetArguments(SourcePath, Filename);
int? exitCode = null;
using (Process exeProcess = Process.Start(startInfo))
{
exeProcess.WaitForExit();
exitCode = exeProcess.ExitCode;
}
}
catch(Exception ex)
{
return false;
}
}
NOTE: Code is shortened for this example
According to MSDN, Process.WaitForExit should return if your process crashes (emphasis added):
When an associated process exits (that is, when it is shut down by the
operation system through a normal or abnormal termination), the system
stores administrative information about the process and returns to the
component that had called WaitForExit().
It appears that your HandBrake process is just hanging and staying alive. The best solution would be to debug that process and figure out where it is crashing, but not closing down. Do you have access to the HandBrakeCLI.exe code?
If you don't have access to the HandBrake.exe code: you could use Process.WaitForExit(Int32) to set a timeout. If the timeout is reached, you may want to manually kill your process via the Process.Kill function, or all subsequent calls to Process.Start(ProcessStartInfo) will not work properly, since they will only return a new process if the process wasn'talready running:
A new Process component that is associated with the process resource,
or null if no process resource is started (for example, if an existing
process is reused).
1)
You should spawn your process and wait for it to terminate in a separate thread, in order to avoid blocking your main thread.
2)
You could use the WaitForExit method that takes the max time to wait for the process as a parameter. You'll then be able to avoid the case a thread of your program is blocked forever.

How do I restart my C# WinForm Application?

Developing a C# .NET 2.0 WinForm Application. Need the application to close and restart itself.
Application.Restart();
The above method has proven to be unreliable.
What is a better way to restart the application?
A much simpler approach that worked for me is:
Application.Restart();
Environment.Exit(0);
This preserves the command-line arguments and works despite event handlers that would normally prevent the application from closing.
The Restart() call tries to exit, starts a new instance anyway and returns. The Exit() call then terminates the process without giving any event handlers a chance to run. There is a very brief period in which both processes are running, which is not a problem in my case, but maybe in other cases.
The exit code 0 in Environment.Exit(0); specifies a clean shutdown. You can also exit with 1 to specify an error occurred.
If you are in main app form try to use
System.Diagnostics.Process.Start( Application.ExecutablePath); // to start new instance of application
this.Close(); //to turn off current app
Unfortunately you can't use Process.Start() to start an instance of the currently running process. According to the Process.Start() docs:
"If the process is already running, no additional process resource is started..."
This technique will work fine under the VS debugger (because VS does some kind of magic that causes Process.Start to think the process is not already running), but will fail when not run under the debugger. (Note that this may be OS-specific - I seem to remember that in some of my testing, it worked on either XP or Vista, but I may just be remembering running it under the debugger.)
This technique is exactly the one used by the last programmer on the project on which I'm currently working, and I've been trying to find a workaround for this for quite some time. So far, I've only found one solution, and it just feels dirty and kludgy to me: start a 2nd application, that waits in the background for the first application to terminate, then re-launches the 1st application. I'm sure it would work, but, yuck.
Edit: Using a 2nd application works. All I did in the second app was:
static void RestartApp(int pid, string applicationName )
{
// Wait for the process to terminate
Process process = null;
try
{
process = Process.GetProcessById(pid);
process.WaitForExit(1000);
}
catch (ArgumentException ex)
{
// ArgumentException to indicate that the
// process doesn't exist? LAME!!
}
Process.Start(applicationName, "");
}
(This is a very simplified example. The real code has lots of sanity checking, error handling, etc)
I might be late to the party but here is my simple solution and it works like a charm with every application I have:
try
{
//run the program again and close this one
Process.Start(Application.StartupPath + "\\blabla.exe");
//or you can use Application.ExecutablePath
//close this one
Process.GetCurrentProcess().Kill();
}
catch
{ }
I had the same exact problem and I too had a requirement to prevent duplicate instances - I propose an alternative solution to the one HiredMind is proposing (which will work fine).
What I am doing is starting the new process with the processId of the old process (the one that triggers the restart) as a cmd line argument:
// Shut down the current app instance.
Application.Exit();
// Restart the app passing "/restart [processId]" as cmd line args
Process.Start(Application.ExecutablePath, "/restart" + Process.GetCurrentProcess().Id);
Then when the new app starts I first parse the cm line args and check if the restart flag is there with a processId, then wait for that process to Exit:
if (_isRestart)
{
try
{
// get old process and wait UP TO 5 secs then give up!
Process oldProcess = Process.GetProcessById(_restartProcessId);
oldProcess.WaitForExit(5000);
}
catch (Exception ex)
{
// the process did not exist - probably already closed!
//TODO: --> LOG
}
}
I am obviously not showing all the safety checks that I have in place etc.
Even if not ideal - I find this a valid alternative so that you don't have to have in place a separate app just to handle restart.
Start/Exit Method
// Get the parameters/arguments passed to program if any
string arguments = string.Empty;
string[] args = Environment.GetCommandLineArgs();
for (int i = 1; i < args.Length; i++) // args[0] is always exe path/filename
arguments += args[i] + " ";
// Restart current application, with same arguments/parameters
Application.Exit();
System.Diagnostics.Process.Start(Application.ExecutablePath, arguments);
This seems to work better than Application.Restart();
Not sure how this handles if your program protects against multiple instance. My guess is you would be better off launching a second .exe which pauses and then starts your main application for you.
It's simple, you just need to call the Application.Restart() method, this will invoke your application to be restarted. You must also exit from the local environment with an error code:
Application.Restart();
Environment.Exit(int errorcode);
You can create an enumeration of error codes so that you application will exit efficeintly.
Another method is to just exit from the application and start the process using the executable path:
Application.Exit();
System.Diagnostics.Process.Start(Application.ExecutablePath);
Try this code:
bool appNotRestarted = true;
This code must also be in the function:
if (appNotRestarted == true) {
appNotRestarted = false;
Application.Restart();
Application.ExitThread();
}
I figured an another solution out, perhaps anyone can use it, too.
string batchContent = "/c \"#ECHO OFF & timeout /t 6 > nul & start \"\" \"$[APPPATH]$\" & exit\"";
batchContent = batchContent.Replace("$[APPPATH]$", Application.ExecutablePath);
Process.Start("cmd", batchContent);
Application.Exit();
Code is simplified so take care of Exceptions and stuff ;)
I fear that restarting the entire application using Process is approaching your problem in the wrong way.
An easier way is to modify the Program.cs file to restart:
static bool restart = true; // A variable that is accessible from program
static int restartCount = 0; // Count the number of restarts
static int maxRestarts = 3; // Maximum restarts before quitting the program
/// <summary>
/// The main entry point for the application.
/// </summary>
[STAThread]
static void Main()
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
while (restart && restartCount < maxRestarts)
{
restart = false; // if you like.. the program can set it to true again
restartCount++; // mark another restart,
// if you want to limit the number of restarts
// this is useful if your program is crashing on
// startup and cannot close normally as it will avoid
// a potential infinite loop
try {
Application.Run(new YourMainForm());
}
catch { // Application has crashed
restart = true;
}
}
}
You are forgetting the command-line options/parameters that were passed in to your currently running instance. If you don't pass those in, you are not doing a real restart. Set the Process.StartInfo with a clone of your process' parameters, then do a start.
For example, if your process was started as myexe -f -nosplash myfile.txt, your method would only execute myexe without all those flags and parameters.
I wanted the new application start up after the old one shuts down.
Using process.WaitForExit() to wait for your own process to shutdown makes no sense. It will always time out.
So, my approach is to use Application.Exit() then wait, but allow events to be processed, for a period of time. Then start a new application with the same arguments as the old.
static void restartApp() {
string commandLineArgs = getCommandLineArgs();
string exePath = Application.ExecutablePath;
try {
Application.Exit();
wait_allowingEvents( 1000 );
} catch( ArgumentException ex ) {
throw;
}
Process.Start( exePath, commandLineArgs );
}
static string getCommandLineArgs() {
Queue<string> args = new Queue<string>( Environment.GetCommandLineArgs() );
args.Dequeue(); // args[0] is always exe path/filename
return string.Join( " ", args.ToArray() );
}
static void wait_allowingEvents( int durationMS ) {
DateTime start = DateTime.Now;
do {
Application.DoEvents();
} while( start.Subtract( DateTime.Now ).TotalMilliseconds > durationMS );
}
You could also use Restarter.
Restarter is an application that automatically monitor and restarts crashed or hung programs and applications. It was originally developed to monitor and restart game servers, but it will do the job for any console or form based program or application
public static void appReloader()
{
//Start a new instance of the current program
Process.Start(Application.ExecutablePath);
//close the current application process
Process.GetCurrentProcess().Kill();
}
Application.ExecutablePath returns your aplication .exe file path
Please follow the order of calls. You might want to place it in a try-catch clause.
The problem of using Application.Restart() is, that it starts a new process but the "old" one is still remaining. Therefor I decided to Kill the old process by using the following code snippet:
if(Condition){
Application.Restart();
Process.GetCurrentProcess().Kill();
}
And it works proper good. In my case MATLAB and a C# Application are sharing the same SQLite database. If MATLAB is using the database, the Form-App should restart (+Countdown) again, until MATLAB reset its busy bit in the database. (Just for side information)
How about create a bat file, run the batch file before closing, and then close the current instance.
The batch file does this:
wait in a loop to check whether the process has exited.
start the process.
Here's my 2 cents:
The sequence Start New Instance->Close Current Instance should work even for the applications that don't allow running multiple copies simultaneously as in this case the new instance may be passed a command-line argument which will indicate that there is a restart in progress so checking for other instances running will not be necessary. Waiting for the first instance to actually finish my be implemented too if it's absolutely imperative that no two intstances are running in parallel.
Application.Restart();
Environment.Exit(0);
I had a similar problem, but mine was related to unmanageable memory leak that I couldn't find on an app that has to run 24/7. With the customer I agreed that safe time to restart the app was 03:00AM if the memory consumption was over the defined value.
I tried Application.Restart, but since it seems to use some mechanism that starts new instance while it is already running, I went for another scheme. I used the trick that file system handles persist until process that created them dies. So, from The Application, i dropped the file to the disk, and didn't Dispose() the handle. I used the file to send 'myself' executable and starting directory also (to add flexibility).
Code:
_restartInProgress = true;
string dropFilename = Path.Combine(Application.StartupPath, "restart.dat");
StreamWriter sw = new StreamWriter(new FileStream(dropFilename, FileMode.Create, FileAccess.ReadWrite, FileShare.ReadWrite));
sw.WriteLine(Application.ExecutablePath);
sw.WriteLine(Application.StartupPath);
sw.Flush();
Process.Start(new ProcessStartInfo
{
FileName = Path.Combine(Application.StartupPath, "VideoPhill.Restarter.exe"),
WorkingDirectory = Application.StartupPath,
Arguments = string.Format("\"{0}\"", dropFilename)
});
Close();
Close() at the end would initiate app shutdown, and file handle I used for StreamWriter here would be held open until process really dies. Then...
Restarter.exe comes into action. It TRIES to read the file in exclusive mode, preventing it to gain access until main app wasn't dead, then starts main app, deletes the file and exists. I guess that it can't be simpler:
static void Main(string[] args)
{
string filename = args[0];
DateTime start = DateTime.Now;
bool done = false;
while ((DateTime.Now - start).TotalSeconds < 30 && !done)
{
try
{
StreamReader sr = new StreamReader(new FileStream(filename, FileMode.Open, FileAccess.ReadWrite, FileShare.ReadWrite));
string[] runData = new string[2];
runData[0] = sr.ReadLine();
runData[1] = sr.ReadLine();
Thread.Sleep(1000);
Process.Start(new ProcessStartInfo { FileName = runData[0], WorkingDirectory = runData[1] });
sr.Dispose();
File.Delete(filename);
done = true;
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
Thread.Sleep(1000);
}
}
I use the following and it does exactly what you are looking for:
ApplicationDeployment ad = ApplicationDeployment.CurrentDeployment;
UpdateCheckInfo info = null;
info = ad.CheckForDetailedUpdate();
if (info.IsUpdateRequired)
{
ad.UpdateAsync(); // I like the update dialog
MessageBox.Show("Application was upgraded and will now restart.");
Environment.Exit(0);
}
for using As logout you need to terminate all app from Ram Cache
so close The Application first and then Rerun it
//on clicking Logout Button
foreach(Form frm in Application.OpenForms.Cast<Form>().ToList())
{
frm.Close();
}
System.Diagnostics.Process.Start(Application.ExecutablePath);
You could enclose your code inside a function and when restart is needed you can just call the function.
Take for instance an application that:
While application is not registered; (upon start) the application should prompt the user to register the application and create a login account.
Once registration is submitted and login credentials are created; the application should restart, check for registration and prompt the user to login with the inserted credentials (so the user can access to all the application features).
Problem:
By building and launching the application from Visual Studio; any of the 4 alternatives bellow will fail to accomplish the tasks required.
/*
* Note(s):
* Take into consideration that the lines bellow don't represent a code block.
* They are just a representation of possibilities,
* that can be used to restart the application.
*/
Application.Restart();
Application.Exit();
Environment.Exit(int errorCode);
Process.GetCurrentProcess().Kill();
What happens is: After creating the Registration, Login and calling Application.Restart(); the application will (strangely) reopen the Registration Form and skip data in a Database (even though the resource is set to "Copy if Newer").
Solution:
Batch Building the application was (for me) a proof that any of the lines above were actually working as expected.
Just not when building and running the application with Visual Studio.
In first place I'd try batch building the application; run it outside Visual Studio and check if Application.Restart() actually works as expected.
Also Check further Info regarding this thread subject:
How do I restart my C# WinForm Application?
I've found a new way that's pretty convenient and has quite a few upsides.
There's never more than one instance running.
Command line args are persisted.
No exit events are raised from the application.
No process handles are broken.
I had a third party application managing my application with Process.Start and using Exit event to reload the application. Many of these solutions would break this implementation which is how I ended up on the following solution.
public static CancellationTokenSource _restartTokenSource;
/// <summary>
/// The main entry point for the application.
/// </summary>
[STAThread]
static void Main(string[] args)
{
// To customize application configuration such as set high DPI settings or default font,
// see https://aka.ms/applicationconfiguration.
ApplicationConfiguration.Initialize();
while (_restartTokenSource == null || _restartTokenSource.IsCancellationRequested)
{
_restartTokenSource = new System.Threading.CancellationTokenSource();
_restartTokenSource.Token.Register(() =>
{
foreach (Form form in Application.OpenForms)
form.Close();
});
Application.Run(new FlashMain(args));
}
}
Since Application.Run blocks until all forms in the application are closed I put this portion of the initialization into a loop that only executes when a CancellationTokenSource is null (the first run) or IsCancellationRequested is true (restart requested).
I register an event on the CancellationTokenSource that closes all forms in the application when .Cancel() is called, therefore unblocking Application.Run and restarting the loop.
Call Program._restartTokenSource.Cancel(); anywhere in the application to restart it.
P.S. This also works great for injecting into a BlazorWebView to restart the application from .NET Core.

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