Application.Run(), Application.Exit() and timers - c#

I have a winforms application that I will be calling through the task scheduler to download files and insert them to a database. However it is unpredictable when the files are available so I have used timer (System.Windws.Forms.Timer) to poll for the files.
static class Program
{
/// <summary>
/// The main entry point for the application.
/// </summary>
[STAThread]
static void Main(string[] args)
{
if (args != null && args.Length > 0)
{
Form1 f1 = new Form1();
if (f1.IsLive)
{
f1.OnLaunch(); // tests DB connection and reads and updates the expiry date list.
if (args[0] == "FullStats")
f1.FullStatsDataPump();
else if (args[0] == "OptionsStats")
{
f1.OptionsStatsTimer_Tick(null, null);
f1.OptionsStatsTimer.Start();
}
else if (args[0] == "OptionsTraded")
{
f1._optionsTradedTimer_Tick(null, null);
f1.OptionsTradedTimer.Start();
}
else
{
EmailManager.InvalidInputArgument(args[0]);
Application.Exit();
}
Application.Run();
}
}
In the above code snippet, OptionsTradedTimer / OptionsStatsTimer both poll for files and then begin processes that end with Application.Exit(). This runs perfectly but then afterwards it gets stuck in an infinite message loop. I thought that Application.Run() would be called immediately after the first timer ticks and thus when Application.Exit() eventually gets called it would end the message loop. But if I step through the code then after that Application.Exit() the program returns to the timer.tick() where it originated and then continues on to the Application.Run() at the bottom. The Application.Run() at the bottom is necessary as without it the timers will only tick once and then the app will exit.
So how do I correctly tell the application to exit? Or where should I be calling Application.Run()?

That sounds somewhat weird - perhaps you should simply move the Application.exit to a seperate procedure and just change some boolean variable if you need to exit the program. In your main program you could wait for the boolean to change and then exit the program once. Additionally, you could set the boolean variable to false at the beginning, so that you doesnt need the run.

I don't think you need to use Application.Exit(). Your Main() method is the entry point to the application; when it returns, the application exits. Generally speaking, Application.Run() is used to start up a windows form that runs until closed. Give this code a try - I haven't tested it, but it should do what you want.
using System.Linq;
using System.Threading;
class MyApplication
{
[STAThread]
static void Main(string[] args)
{
const string ARG_SHOWFORM = "ShowForm";
const string ARG_STATS = "OptionsStats";
const string ARG_TRADED = "OptionsTraded";
if (args.Contains(ARG_SHOWFORM) || args.Length == 0) {
Application.Run(new Form1()); //This will block until the form is closed.
//Make sure all your supporting logic is placed into the Form.Loaded event on the form (i.e.
//get it out of the Main() method).
return;
}
if (args.Contains(ARG_STATS))
OptionsStatsMethod();
else if (args.Contains(ARG_TRADED))
OptionsTradedMethod();
else
EmailManager.InvalidInputArgument(args[0]);
}
private void OptionsTradedMethod()
{
while (true) {
if (downloadSuccessful) //Use a method here that returns a boolean if the download succeeded.
break;
else
Thread.Sleep(DEFAULT_WAIT_TIME_MS);
}
}
private void OptionsStatsMethod()
{
while (true) {
if (downloadSuccessful) //Use a method here that returns a boolean if the download succeeded.
break;
else
Thread.Sleep(DEFAULT_WAIT_TIME_MS);
}
}
}

Can't delete the question so might as well answer it.
The problem only occurs if the timer reaches the Application.Exit() line the first time it runs. (i.e. if the file is available already when the program is run). In this case Application.Exit() is called before Application.Run() where as if the timer doesn't reach the Application.Exit() on its first run (i.e. file is not yet available) then Application.Run() gets called and Application.Exit() only gets called later.
So to solve this I just added a condition in the timers' tick methods to make sure they don't so anything on their first run.
I don't agree with restructuring the program as the way it stands I can run it through the task scheduler to download the files daily without a form and with the polling functionality and I can also run it through VS as a normal winforms app with buttons for testing, debugging and downloading files when something went wrong.

To keep your main method running(keep it's thread alive) you can use Thread.Sleep instead of Application.Run(). Try this:
Thread.Sleep(System.Threading.Timeout.Infinite);
and instead of Application.Exit() use:
Process.GetCurrentProcess().Kill();
This way it works, but consider using windows sevices for this.

Related

What is the proper way to exit a WinForms application from static void Main() entry point

I know there are other questions about Environment.Exit but I would like the answer in respect to the specific set of facts described here.
What is the proper way to exit the static void Main() entry point of a WinForms application if the goals are to have the application shut down cleanly, free up all memory, and leave nothing in an unstable state. Is it as simple as Environment.Exit(0)?
namespace MyApp
{
static class Program
{
[STAThread]
static void Main()
{
bool authorized=false;
authorized = Test(System.Security.Principal.WindowsIdentity.GetCurrent().Name);
if (!authorized)
{
MessageBox.Show("Sorry. Maybe next time.",
MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
Environment.Exit(0); //?
}
else
{
Application.Run(new Form1());
}
}
}
}
There are two things that can happen in your code as written:
Test, whatever it does, returns false; your code shows a MessageBox. You don't need to do anything else, no Environment.Exit etc, just show the messagebox; the app will quit when they click OK, because there is nothing stopping the code flow from leaving Main (other than the messagebox being open)
Test returns true, your app runs and shows Form1. The app will quit when Form1 closes, because Application.Run will return.
There's nothing magic about winforms apps Main method; it's the fact that Application.Run doesn't return while the form passed into it is still open that prevents the app from exiting. In the case where you don't open Form1, you open a MessageBox instead, which also blocks the execution flow until it is dismissed

How do I know if Process.WaitForExit() expired due to main application close

I have a C# console program "A" to monitor 4 instances of another application "B".
The console program creates one thread per instance of "B", and each thread launches "B" using Process.Start(). Then the thread waits 3 seconds using Process.WaitForExit(3000);
After that time, it checks if the instance of the application "B" is working. If it is ok, then waits again. Otherwise, if it doesn't work or if it has finished, it relaunches it. When the user closes the console program, all applications are expected to end.
However, when the application "A" is closed using the console's close button, WaitForExit() is resumed in all threads and it causes the applications "B" to be relaunched.
I would like to detect if WaitForExit() resumed due to a failure of the monitored application "B", or because the main app "A" is exiting. In this case, the application "B" won't be relaunched, and the problem will be solved.
I tried to capture the closing event using:
[DllImport("Kernel32")]
public static extern bool SetConsoleCtrlHandler(HandlerRoutine Handler, bool Add);
The problem was that WaitForExit() was resumed before the handler routine is called.
More information:
The Main() method launches the Threads:
for(int i = 0; i < 4; i++)
{
Thread t = new Thread(() => MonitorizeApp(arguments));
t.IsBackground = true;
t.Start();
}
I also tried to change the threads from background to foreground, so that main app doesn't exit, but the result is the same.
Each thread launches and monitorizes one instance of the 2nd application:
MonitorizeApp(string arguments)
{
LaunchProcess(arguments);
while(!_closing)
{
appProcess.WaitForExit(3000);
if (!_closing)
{
if ((appProcess != null) && (!appProcess.HasExited))
DoSomeMonitoring();
else
{
Console.WriteLine("WARNING: The application finished");
Thread.Sleep(500);
if (!_closing)
{
Console.WriteLine("Re-launch");
LaunchProcess(arguments);
inicial = true;
}
}
}
}
Console.WriteLine("\nClosing...\n");
if(appProcess != null)
{
if(!appProcess.HasExited)
appProcess.Kill();
appProcess.Dispose();
}
}
_closing is a variable set from the main thread, when the console is closed.
I did this using SetConsoleCtrlHandler:
[DllImport("Kernel32")]
public static extern bool SetConsoleCtrlHandler(HandlerRoutine Handler, bool Add);
public delegate bool HandlerRoutine(CtrlTypes CtrlType);
private static bool ConsoleCtrlCheck(CtrlTypes ctrlType)
{
MonitoredApp.closing = true;
Thread.Sleep(1000);
closing = true;
Environment.Exit(-1);
return true;
}
I suspect your only option is to have the main program's exit routine check to see if any of the child processes are running and, if so, terminate them. I'm a little surprised that your 500 ms sleep followed by the _closing check doesn't catch this. Although, looking at your code example I don't see a _closing flag being set (unless _closing is the backing field for MonitoredApp.closing).
You might consider changing that _closing boolean to a ManualResetEvent that the main program sets. It's quite possible that the compiler is optimizing away the check of _closing. You could also mark _closing as volatile, which might change the behavior. Remember, this stuff is all happening asynchronously, so you have to worry about race conditions.
Even with that, you'll likely still run into problems and you'll have to make sure that the main application closes all existing child processes before it exits. You simply cannot guarantee in what order the operating system is going to shut things down.
You could avoid the problem by disabling the close button. See my blog entry, http://blog.mischel.com/2008/07/14/going-too-far-back/, for an example. If you delete the Close menu item, clicking the X won't close the window.
Of course, then your users will have to type the exit command in your window. And you might still have problems if the user closes the window from Task Manager or some other such application.

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.

C# Application.Run without Form

Is it possible to call Application.Run, but to not pass a form parameter, or is there an alternative if there’s no form to call?
The Run method doesn’t seem to have any overloads that don’t accept a form.
For example, if I wanted to instantiate a class first, and then have that call the form, is there way to do the equivalent of:
Application.Run(myClass);
Just to clarify, I do still want the functionality that .Run() provides. That is, establish a loop to keep the application running, but instead of tracking a form, track a class or other object.
This is relating to the compact framework initially. I assume that's why the Run method doesn't have the overload I was looking for.
The Run method doesn’t seem to have any overloads that don’t accept a form.
Uh... http://msdn.microsoft.com/en-us/library/ms157900.aspx
Application.Run Method
Begins running a standard application message loop on the current thread, without a form.
public static void Run()
I'm not clear whether you want to do:
You want to load your form somewhere else other than the Main()
Or Run a console or service application with no UI.
For (1):
static void main()
{
//Your program starts running here<<<
//Do some stuff...
FormRunner a = new FormRunner();
a.RunForm();
} // << And ends here
class FormRunner {
public void RunForm() {
Application.Run(new Form());
}
//You could call which ever form you want from here?
} // << And ends here
What you need to know is your program starts from the first line of the main and ends at the last. However, when you call Application.Run(FORM) it loads up a windows message loop for that form. Its a special loop that keeps the program still in the main and waits for events (they're called Windows Messages in win32 API)
And so the program does not end until the user clicks the close button. When this happens, thats when your program actually will return from its Main.
(2) So now if you just want a pure console app with no forms:
static void main()
{
AcceptInputs()
DrawScreen()
//Do something else.
//Make sure your flow stays within the main
} // << Once you come here you're done.
void AcceptInputs()
{
while(true) {
//Keep accepting input
break; // Call break when you're done. You'll be back in the main
}
}
I hope that helped.
You can use the overload of Application.Run that accepts an application context as its only parameter. An ApplicationContext is basically just a class that you can inherit from and add any functionality you like. See the example in the link for more information.
using System;
using System.Windows.Forms;
static class Program
[STAThread]
static void Main() {
Application.Run(new myClass());
}
internal class myClass : ApplicationContext {
public myClass() {
Application.Run(new myWindow());
}
}
}
The problem here, though, is that something will have to call this instance of myClass and tell it to exit or else the program will just keep running even after all forms are closed. And calling ExitThread() in the constructor is ignored.

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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