I am pretty new to c# development / compact frame work so if this is a dumb question I appologise.
I have a application that has multiple forms, the main form owns and launches a splash screen, then once the loading is all done I ditch the splash screen.
My problem is that during the start up it is possible for me to launch multiple instances of my application.
I am quiet unsure why this is happening, I am doing the main loading of my applications engine in the method called from the forms load event. It seems that up to a certain point it is possible to create a new instances of the application, but then after a certain point it brings the loaded instance to the foreground rather than creating a new one.
I have been looking into a few ways to try and solve this and am familiair with using named mutexes in other languages but it seems that this isn't supported. How is it possible to complish this in C# using the compact framework API. I've tried using the method call
iMutex.WaitOne();
but all this does is stack up instances of my application until the current application is killed.
I've seen a few postings in the news groups about using unmanaged code to create the mutex, is this really the only solution ?
I hope my posting is clear and someone out there can explain where I am going wrong.
> I am pretty new to c# development / compact frame work so if this is a dumb > question I appologise.
> I have a application that has multiple forms, the main form owns and > launches a splash screen, then once the loading is all done I ditch the > splash screen.
> My problem is that during the start up it is possible for me to launch > multiple instances of my application.
> I am quiet unsure why this is happening, I am doing the main loading of my > applications engine in the method called from the forms load event. It seems > that up to a certain point it is possible to create a new instances of the > application, but then after a certain point it brings the loaded instance to > the foreground rather than creating a new one.
> I have been looking into a few ways to try and solve this and am familiair > with using named mutexes in other languages but it seems that this isn't > supported. > How is it possible to complish this in C# using the compact framework API. > I've tried using the method call
> iMutex.WaitOne();
> but all this does is stack up instances of my application until the current > application is killed.
> I've seen a few postings in the news groups about using unmanaged code to > create the mutex, is this really the only solution ?
> I hope my posting is clear and someone out there can explain where I am > going wrong.
> > I am pretty new to c# development / compact frame work so if this is a dumb > > question I appologise.
> > I have a application that has multiple forms, the main form owns and > > launches a splash screen, then once the loading is all done I ditch the > > splash screen.
> > My problem is that during the start up it is possible for me to launch > > multiple instances of my application.
> > I am quiet unsure why this is happening, I am doing the main loading of my > > applications engine in the method called from the forms load event. It seems > > that up to a certain point it is possible to create a new instances of the > > application, but then after a certain point it brings the loaded instance to > > the foreground rather than creating a new one.
> > I have been looking into a few ways to try and solve this and am familiair > > with using named mutexes in other languages but it seems that this isn't > > supported. > > How is it possible to complish this in C# using the compact framework API. > > I've tried using the method call
> > iMutex.WaitOne();
> > but all this does is stack up instances of my application until the current > > application is killed.
> > I've seen a few postings in the news groups about using unmanaged code to > > create the mutex, is this really the only solution ?
> > I hope my posting is clear and someone out there can explain where I am > > going wrong.
> I am pretty new to c# development / compact frame work so if this is a > dumb > question I appologise.
> I have a application that has multiple forms, the main form owns and > launches a splash screen, then once the loading is all done I ditch the > splash screen.
> My problem is that during the start up it is possible for me to launch > multiple instances of my application.
> I am quiet unsure why this is happening, I am doing the main loading of my > applications engine in the method called from the forms load event. It > seems > that up to a certain point it is possible to create a new instances of the > application, but then after a certain point it brings the loaded instance > to > the foreground rather than creating a new one.
> I have been looking into a few ways to try and solve this and am familiair > with using named mutexes in other languages but it seems that this isn't > supported. > How is it possible to complish this in C# using the compact framework API. > I've tried using the method call
> iMutex.WaitOne();
> but all this does is stack up instances of my application until the > current > application is killed.
> I've seen a few postings in the news groups about using unmanaged code to > create the mutex, is this really the only solution ?
> I hope my posting is clear and someone out there can explain where I am > going wrong.
I am still a bit confused, you state that the single instance behavior is default in the windows mobile platform. Can you answer how I would have broken this so that during the first few seconds of start up it is possible to start up another instance?
The application I am working on was written by another developer, I'm just trying to fix the dirty coding ;-)
> > I am pretty new to c# development / compact frame work so if this is a > > dumb > > question I appologise.
> > I have a application that has multiple forms, the main form owns and > > launches a splash screen, then once the loading is all done I ditch the > > splash screen.
> > My problem is that during the start up it is possible for me to launch > > multiple instances of my application.
> > I am quiet unsure why this is happening, I am doing the main loading of my > > applications engine in the method called from the forms load event. It > > seems > > that up to a certain point it is possible to create a new instances of the > > application, but then after a certain point it brings the loaded instance > > to > > the foreground rather than creating a new one.
> > I have been looking into a few ways to try and solve this and am familiair > > with using named mutexes in other languages but it seems that this isn't > > supported. > > How is it possible to complish this in C# using the compact framework API. > > I've tried using the method call
> > iMutex.WaitOne();
> > but all this does is stack up instances of my application until the > > current > > application is killed.
> > I've seen a few postings in the news groups about using unmanaged code to > > create the mutex, is this really the only solution ?
> > I hope my posting is clear and someone out there can explain where I am > > going wrong.
The CF enforces it, but if you get into the CF initialization before it does it's check, you can get multiple instances. Add a mutex check at the start of the app and handle the second instance there (which is how it should be set up in the first place IMHO).
-Chris
"Guus Davidson" <GuusDavid...@discussions.microsoft.com> wrote in message
> I am still a bit confused, you state that the single instance behavior is > default in the windows mobile platform. > Can you answer how I would have broken this so that during the first few > seconds of start up it is possible to start up another instance?
> The application I am working on was written by another developer, I'm just > trying to fix the dirty coding ;-)
> thanks in advance > Guus Davidson
> "Daniel Moth" wrote:
>> The single instance behaviour is the default on the Windows Mobile >> platform >> (not true on custom Windows CE).
>> > I am pretty new to c# development / compact frame work so if this is a >> > dumb >> > question I appologise.
>> > I have a application that has multiple forms, the main form owns and >> > launches a splash screen, then once the loading is all done I ditch the >> > splash screen.
>> > My problem is that during the start up it is possible for me to launch >> > multiple instances of my application.
>> > I am quiet unsure why this is happening, I am doing the main loading of >> > my >> > applications engine in the method called from the forms load event. It >> > seems >> > that up to a certain point it is possible to create a new instances of >> > the >> > application, but then after a certain point it brings the loaded >> > instance >> > to >> > the foreground rather than creating a new one.
>> > I have been looking into a few ways to try and solve this and am >> > familiair >> > with using named mutexes in other languages but it seems that this >> > isn't >> > supported. >> > How is it possible to complish this in C# using the compact framework >> > API. >> > I've tried using the method call
>> > iMutex.WaitOne();
>> > but all this does is stack up instances of my application until the >> > current >> > application is killed.
>> > I've seen a few postings in the news groups about using unmanaged code >> > to >> > create the mutex, is this really the only solution ?
>> > I hope my posting is clear and someone out there can explain where I am >> > going wrong.
I have implemented a named mutex as suggested in one of the earlier postings, but I am still able to create multiple instances of my application.
I have added in a log4net logging framework to see if it will help me track down where the issue is. I have my logging setup so that it should just append to the log file.
I have set up my application so that on the device it can be started by pressing one of the hardware buttons. My test here is to press the button a couple of times and then while everything is loading up check out the "running applications".
From my log file I am only ever seeing one entry point into the "Main" method, yet I can clearly see that there are several instances of my application running in the running application list.
I have enclosed the relivent code snippets from my application, could anyone tell me what I am doing wrong ?
thanks in advance
Guus Davidson
<Code Snippet from my application>
//My main method using the IsInstanceMethod, this creates a named mutex is one doen't exist. //I am passing back a reference to metex handle so I can release the mutex when I am finished. //I have added in log4net and am using a singleton logger within my application.
static void Main() { iLog.Info("Main"); int mutexhandle = 0; if (!IsInstanceRunning(ref mutexhandle)) { // just making a local copy due to threading fears int mutexhnd = mutexhandle; // Wait until it is safe to enter.
if (IsActivateProperly()) { Application.Run(new MainForm()); } else { Application.Run(new RegistrationForm()); } if (ReleaseMutex(mutexhnd)) { iLog.Info("mutex released"); } } iLog.Info("~Main");
}
//MainForm constructor, the bugs comment isn't mine its dirty coding and needs removed.
public MainForm() { iLog.Info("MainForm constructor");
this.Enabled = false;
//bugs: it will throw an ArgumentException given the app.config file is not in place System.Threading.Thread.Sleep(500); InitializeComponent(); iLog.Info("~MainForm constructor");
}
//My Splash screen start method, called as a result of the splashFormThread in the MainForm_Load
public void StartSplash() { iLog.Info("StartSplash"); if (iSplashForm == null) { iSplashForm = new SABannerForm(); } iLog.Info("running splash"); Application.Run(iSplashForm); iLog.Info("~running splash"); iLog.Info("~StartSplash");
// editied version of a method found on form somewhere // thought I need to releasethe mutex once I've created it so am passing back the handle public static bool IsInstanceRunning(ref int aMutexHandle) { string appname = System.Reflection.Assembly.GetExecutingAssembly().GetName().Name; iLog.Info(appname + "IsInstanceRunning"); aMutexHandle = CreateMutex(IntPtr.Zero, true, appname); bool result = false; if (aMutexHandle != 0) { if (GetLastError() == ERROR_ALREADY_EXISTS) { iLog.Info(appname + " application does exist"); result = true; } } iLog.Info(appname + "~IsInstanceRunning"); return result;
I haven't looked at all your code but, just in case, you do realise that running programs shows all top level captioned windows in your application right? To see the number of processes use the Remote Process Viewer tool from the start menu.
Also if you are genuinely observing this behaviour start building a repro. Start a new project from scratch and try to replicate it in there adding bits of code from your original project (especially important since you didn't write the original code).
> I have implemented a named mutex as suggested in one of the earlier > postings, but I am still able to create multiple instances of my > application.
> I have added in a log4net logging framework to see if it will help me > track > down where the issue is. > I have my logging setup so that it should just append to the log file.
> I have set up my application so that on the device it can be started by > pressing one of the hardware buttons. > My test here is to press the button a couple of times and then while > everything is loading up check out the "running applications".
> From my log file I am only ever seeing one entry point into the "Main" > method, yet I can clearly see that there are several instances of my > application running in the running application list.
> I have enclosed the relivent code snippets from my application, could > anyone > tell me what I am doing wrong ?
> thanks in advance
> Guus Davidson
> <Code Snippet from my application>
> //My main method using the IsInstanceMethod, this creates a named mutex is > one doen't exist. > //I am passing back a reference to metex handle so I can release the mutex > when I am finished. > //I have added in log4net and am using a singleton logger within my > application.
> static void Main() > { > iLog.Info("Main"); > int mutexhandle = 0; > if (!IsInstanceRunning(ref mutexhandle)) > { > // just making a local copy due to threading fears > int mutexhnd = mutexhandle; > // Wait until it is safe to enter.
> //MainForm constructor, the bugs comment isn't mine its dirty coding and > needs removed.
> public MainForm() > { > iLog.Info("MainForm constructor");
> this.Enabled = false;
> //bugs: it will throw an ArgumentException given the app.config file is > not > in place > System.Threading.Thread.Sleep(500); > InitializeComponent(); > iLog.Info("~MainForm constructor"); > }
> //My Splash screen start method, called as a result of the > splashFormThread > in the MainForm_Load
> // editied version of a method found on form somewhere > // thought I need to releasethe mutex once I've created it so am passing > back the handle > public static bool IsInstanceRunning(ref int aMutexHandle) > { > string appname = > System.Reflection.Assembly.GetExecutingAssembly().GetName().Name; > iLog.Info(appname + "IsInstanceRunning"); > aMutexHandle = CreateMutex(IntPtr.Zero, true, appname); > bool result = false; > if (aMutexHandle != 0) > { > if (GetLastError() == ERROR_ALREADY_EXISTS) > { > iLog.Info(appname + " application does exist"); > result = true; > } > } > iLog.Info(appname + "~IsInstanceRunning"); > return result; > }
If you're using a named mutex properly, I can't see how it's possible to have multiple instances running. Show us some code. "Running Programs" shows all top-level windows (so all forms) in your app - not actual processes.
-- Chris Tacke OpenNETCF Consulting Managed Code in the Embedded World www.opennetcf.com --
"Guus Davidson" <GuusDavid...@discussions.microsoft.com> wrote in message
> I have implemented a named mutex as suggested in one of the earlier > postings, but I am still able to create multiple instances of my > application.
> I have added in a log4net logging framework to see if it will help me > track > down where the issue is. > I have my logging setup so that it should just append to the log file.
> I have set up my application so that on the device it can be started by > pressing one of the hardware buttons. > My test here is to press the button a couple of times and then while > everything is loading up check out the "running applications".
> From my log file I am only ever seeing one entry point into the "Main" > method, yet I can clearly see that there are several instances of my > application running in the running application list.
> I have enclosed the relivent code snippets from my application, could > anyone > tell me what I am doing wrong ?
> thanks in advance
> Guus Davidson
> <Code Snippet from my application>
> //My main method using the IsInstanceMethod, this creates a named mutex is > one doen't exist. > //I am passing back a reference to metex handle so I can release the mutex > when I am finished. > //I have added in log4net and am using a singleton logger within my > application.
> static void Main() > { > iLog.Info("Main"); > int mutexhandle = 0; > if (!IsInstanceRunning(ref mutexhandle)) > { > // just making a local copy due to threading fears > int mutexhnd = mutexhandle; > // Wait until it is safe to enter.
> //MainForm constructor, the bugs comment isn't mine its dirty coding and > needs removed.
> public MainForm() > { > iLog.Info("MainForm constructor");
> this.Enabled = false;
> //bugs: it will throw an ArgumentException given the app.config file is > not > in place > System.Threading.Thread.Sleep(500); > InitializeComponent(); > iLog.Info("~MainForm constructor"); > }
> //My Splash screen start method, called as a result of the > splashFormThread > in the MainForm_Load
> // editied version of a method found on form somewhere > // thought I need to releasethe mutex once I've created it so am passing > back the handle > public static bool IsInstanceRunning(ref int aMutexHandle) > { > string appname = > System.Reflection.Assembly.GetExecutingAssembly().GetName().Name; > iLog.Info(appname + "IsInstanceRunning"); > aMutexHandle = CreateMutex(IntPtr.Zero, true, appname); > bool result = false; > if (aMutexHandle != 0) > { > if (GetLastError() == ERROR_ALREADY_EXISTS) > { > iLog.Info(appname + " application does exist"); > result = true; > } > } > iLog.Info(appname + "~IsInstanceRunning"); > return result; > }
There was a report like this in, I think, the last Windows CE chat. It appears that it might be a problem with using CreateMutex( NULL, TRUE, name ). It seemed that the poster was saying that he was able to do this in two programs and get something other than ERROR_ALREADY_EXISTS from both. I was expecting him to post the repro here, but I didn't see anything wrong with the code and suggested that he try getting the mutex without trying to take ownership and use WaitForSingleObject() to get it, timing out and exiting if that didn't return in a second or two.
Paul T.
"<ctacke/>" <ctacke[@]opennetcf[dot]com> wrote in message
> If you're using a named mutex properly, I can't see how it's possible to > have multiple instances running. Show us some code. "Running Programs" > shows all top-level windows (so all forms) in your app - not actual > processes.
> -- > Chris Tacke > OpenNETCF Consulting > Managed Code in the Embedded World > www.opennetcf.com > --
>> I have implemented a named mutex as suggested in one of the earlier >> postings, but I am still able to create multiple instances of my >> application.
>> I have added in a log4net logging framework to see if it will help me >> track >> down where the issue is. >> I have my logging setup so that it should just append to the log file.
>> I have set up my application so that on the device it can be started by >> pressing one of the hardware buttons. >> My test here is to press the button a couple of times and then while >> everything is loading up check out the "running applications".
>> From my log file I am only ever seeing one entry point into the "Main" >> method, yet I can clearly see that there are several instances of my >> application running in the running application list.
>> I have enclosed the relivent code snippets from my application, could >> anyone >> tell me what I am doing wrong ?
>> thanks in advance
>> Guus Davidson
>> <Code Snippet from my application>
>> //My main method using the IsInstanceMethod, this creates a named mutex >> is >> one doen't exist. >> //I am passing back a reference to metex handle so I can release the >> mutex >> when I am finished. >> //I have added in log4net and am using a singleton logger within my >> application.
>> static void Main() >> { >> iLog.Info("Main"); >> int mutexhandle = 0; >> if (!IsInstanceRunning(ref mutexhandle)) >> { >> // just making a local copy due to threading fears >> int mutexhnd = mutexhandle; >> // Wait until it is safe to enter.
>> //MainForm constructor, the bugs comment isn't mine its dirty coding and >> needs removed.
>> public MainForm() >> { >> iLog.Info("MainForm constructor");
>> this.Enabled = false;
>> //bugs: it will throw an ArgumentException given the app.config file is >> not >> in place >> System.Threading.Thread.Sleep(500); >> InitializeComponent(); >> iLog.Info("~MainForm constructor"); >> }
>> //My Splash screen start method, called as a result of the >> splashFormThread >> in the MainForm_Load
>> // editied version of a method found on form somewhere >> // thought I need to releasethe mutex once I've created it so am passing >> back the handle >> public static bool IsInstanceRunning(ref int aMutexHandle) >> { >> string appname = >> System.Reflection.Assembly.GetExecutingAssembly().GetName().Name; >> iLog.Info(appname + "IsInstanceRunning"); >> aMutexHandle = CreateMutex(IntPtr.Zero, true, appname); >> bool result = false; >> if (aMutexHandle != 0) >> { >> if (GetLastError() == ERROR_ALREADY_EXISTS) >> { >> iLog.Info(appname + " application does exist"); >> result = true; >> } >> } >> iLog.Info(appname + "~IsInstanceRunning"); >> return result; >> }
com> wrote in message news:escsCkh7GHA.4604@TK2MSFTNGP03.phx.gbl... > There was a report like this in, I think, the last Windows CE chat. It > appears that it might be a problem with using CreateMutex( NULL, TRUE, > name ). It seemed that the poster was saying that he was able to do this > in two programs and get something other than ERROR_ALREADY_EXISTS from > both. I was expecting him to post the repro here, but I didn't see > anything wrong with the code and suggested that he try getting the mutex > without trying to take ownership and use WaitForSingleObject() to get it, > timing out and exiting if that didn't return in a second or two.
> Paul T.
> "<ctacke/>" <ctacke[@]opennetcf[dot]com> wrote in message > news:%239XoIYf7GHA.4620@TK2MSFTNGP02.phx.gbl... >> If you're using a named mutex properly, I can't see how it's possible to >> have multiple instances running. Show us some code. "Running Programs" >> shows all top-level windows (so all forms) in your app - not actual >> processes.
>> -- >> Chris Tacke >> OpenNETCF Consulting >> Managed Code in the Embedded World >> www.opennetcf.com >> --
>>> I have implemented a named mutex as suggested in one of the earlier >>> postings, but I am still able to create multiple instances of my >>> application.
>>> I have added in a log4net logging framework to see if it will help me >>> track >>> down where the issue is. >>> I have my logging setup so that it should just append to the log file.
>>> I have set up my application so that on the device it can be started by >>> pressing one of the hardware buttons. >>> My test here is to press the button a couple of times and then while >>> everything is loading up check out the "running applications".
>>> From my log file I am only ever seeing one entry point into the "Main" >>> method, yet I can clearly see that there are several instances of my >>> application running in the running application list.
>>> I have enclosed the relivent code snippets from my application, could >>> anyone >>> tell me what I am doing wrong ?
>>> thanks in advance
>>> Guus Davidson
>>> <Code Snippet from my application>
>>> //My main method using the IsInstanceMethod, this creates a named mutex >>> is >>> one doen't exist. >>> //I am passing back a reference to metex handle so I can release the >>> mutex >>> when I am finished. >>> //I have added in log4net and am using a singleton logger within my >>> application.
>>> static void Main() >>> { >>> iLog.Info("Main"); >>> int mutexhandle = 0; >>> if (!IsInstanceRunning(ref mutexhandle)) >>> { >>> // just making a local copy due to threading fears >>> int mutexhnd = mutexhandle; >>> // Wait until it is safe to enter.
>>> //MainForm constructor, the bugs comment isn't mine its dirty coding and >>> needs removed.
>>> public MainForm() >>> { >>> iLog.Info("MainForm constructor");
>>> this.Enabled = false;
>>> //bugs: it will throw an ArgumentException given the app.config file is >>> not >>> in place >>> System.Threading.Thread.Sleep(500); >>> InitializeComponent(); >>> iLog.Info("~MainForm constructor"); >>> }
>>> //My Splash screen start method, called as a result of the >>> splashFormThread >>> in the MainForm_Load
>>> // editied version of a method found on form somewhere >>> // thought I need to releasethe mutex once I've created it so am passing >>> back the handle >>> public static bool IsInstanceRunning(ref int aMutexHandle) >>> { >>> string appname = >>> System.Reflection.Assembly.GetExecutingAssembly().GetName().Name; >>> iLog.Info(appname + "IsInstanceRunning"); >>> aMutexHandle = CreateMutex(IntPtr.Zero, true, appname); >>> bool result = false; >>> if (aMutexHandle != 0) >>> { >>> if (GetLastError() == ERROR_ALREADY_EXISTS) >>> { >>> iLog.Info(appname + " application does exist"); >>> result = true; >>> } >>> } >>> iLog.Info(appname + "~IsInstanceRunning"); >>> return result; >>> }
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