Chuck,
I imagine you are cycling through all the process names and determining
if one exists already (or something equally painful).
Using the mutex, you basically are blocking access to other mutexes with
the same name. Your code, instead of running then checking all other
processes to see if there is a similar one, would just have to check if a
well known, unique name exists. The code goes something like this:
public class EntryPoint
{
public static void Main()
{
// Was the mutex acquired?
bool pblnAcquired = false;
// Try and acquire the mutex. Use the full type name as the mutex
name.
using (Mutex pobjMutex = new Mutex(true,
typeof(EntryPoint).FullName, ref pblnAcquired)
{
// If the mutex was not acquired, then get out.
if (!pblnAcquired)
// Get out.
return;
// Run the application loop here.
Application.Run(new MainForm());
}
// Get out.
return;
}
--
- Nicholas Paldino [.NET/C# MVP]
-
mvp@spam.guard.caspershouse.com
"Chuck" <ceatley@austin.rr.com> wrote in message
news:gYlAc.5247$4g1.2785@fe2.texas.rr.com...[color=blue]
> Thanks, Nicholas, for your advice.
>
> I will check out the use of the Mutex method to prevent multiple[/color]
instances.[color=blue]
> The way I am doing it is too slow.
>
> The idea of running my connection code before I run Application.Run()[/color]
sounds[color=blue]
> interesting. I will, also, look into doing that.
>
> I did, however, find a way to make things work. I moved the
> Application.ExitThread() call to MainFrame_Load, the handler for the Load
> event. I then used the Boolean switch that I set in the catch block to
> determine if I wanted to do normal load things or abort. It works!
>
> Chuck.
> "Nicholas Paldino [.NET/C# MVP]" <mvp@spam.guard.caspershouse.com> wrote[/color]
in[color=blue]
> message news:%23FPl$nJVEHA.2388@TK2MSFTNGP09.phx.gbl...[color=green]
> > Chuck,
> >
> > First, I think that the way that you are checking for a running[/color]
> instance[color=green]
> > isn't the best. You can easily use a named mutex (use the Mutex class[/color]
> from[color=green]
> > the System.Threading namespace) to keep multiple instances of your
> > application from running. I like to use the full name of the entry[/color][/color]
point[color=blue][color=green]
> > type as the mutex name (it's pretty unique).
> >
> > As for your issue with the exception, I think that you should not[/color][/color]
try[color=blue]
> to[color=green]
> > exit the application during the constructor of the form that will handle[/color]
> the[color=green]
> > main windows message processing. You should establish your database
> > connection outside of the form constructor (before the Run method is
> > called), and then pass the connection to the Form if it connects
> > sucessfully. Otherwise, don't call Run at all.
> >
> > Hope this helps.
> >
> >
> > --
> > - Nicholas Paldino [.NET/C# MVP]
> > -
mvp@spam.guard.caspershouse.com
> >
> > "Chuck" <ceatley@austin.rr.com> wrote in message
> > news:iklAc.1196$M96.440@fe2.texas.rr.com...[color=darkred]
> > > Hello everybody,
> > >
> > > I need to abort execution during start up, while the constructor[/color][/color][/color]
called[color=blue]
> by[color=green][color=darkred]
> > > Application.Run is executing.
> > >
> > > If the database fails to connect during my application's startup I[/color][/color][/color]
want[color=blue]
> to[color=green][color=darkred]
> > > display a message (no problem here) and then abort the program.[/color][/color][/color]
However[color=blue]
> ,[color=green][color=darkred]
> > > after the attached code executes I end up with my main form and a wait
> > > cursor! If I click on the X the form closes. Boss doesn't think an
> > > unhandled exception will impress our customers :) Can't say that I
> > > disagree.
> > >
> > > Anybody have any ideas what I am doing wrong? (Besides, programming[/color][/color][/color]
for[color=blue]
> a[color=green][color=darkred]
> > > living).
> > >
> > > public MainFrame() //MDI appication
> > > {
> > > //
> > > // Required for Windows Form Designer support
> > > //
> > > InitializeComponent();
> > > try
> > > {
> > > Initilize(); //attempts to connect to remote database. throws if[/color][/color][/color]
it[color=blue][color=green][color=darkred]
> > > can't.
> > > }
> > > catch(System.Net.WebException we) // this is thrown when the[/color][/color][/color]
remote[color=blue][color=green][color=darkred]
> > > database can't be found.
> > > {
> > > string message = we.Message; //message explaining that database[/color][/color]
> can't[color=green][color=darkred]
> > > be found. (my text);
> > > message += "\nNotify System Administrator.\nClosing application";
> > > //some add-on text.
> > > MessageBox.Show(message,"Database
> > > Error!",MessageBoxButtons.OK,MessageBoxIcon.Error) ;
> > > connectFailed = true; //needed to prevent OnLoad event handler[/color][/color]
> from[color=green][color=darkred]
> > > doing its thing. Form loads even though I have called Exit!
> > > Application.ExitThread(); //This doesn't seem to work. Neither[/color][/color]
> does[color=green][color=darkred]
> > > Application.Exit() or this.Close();
> > > }
> > > catch(Exception e)
> > > {
> > > throw e; // just a place to put a break point for debugging.
> > > }
> > > }
> > >
> > > [STAThread]
> > > static void Main()
> > > {
> > > Application.EnableVisualStyles(); // I am running XP pro.
> > > //Get the running instance.
> > > Process instance = RunningInstance(); //checks for a running[/color][/color]
> instance[color=green][color=darkred]
> > > of the application. Uses win32 API
> > > if (instance == null)
> > > {
> > > //There isn't another instance, show our form.
> > > SplashScreen.ShowSplashScreen(); // runs on separate thread.
> > > Application.DoEvents();
> > > Application.Run(new MainFrame());
> > > }
> > > else
> > > {
> > > //There is another instance of this process.
> > > HandleRunningInstance(instance);
> > > }
> > > }
> > >
> > >
> > >
> > >[/color]
> >
> >[/color]
>
>[/color]
