Question

I have a windows service that has a custom configuration section. In the configSectionHandler class I am using attributes on the properties to validate the settings like this:

    //ProcessingSleepTime Property     [ConfigurationProperty('ProcessingSleepTime', DefaultValue = 1000, IsRequired = false)]     [IntegerValidator(MinValue = 5, MaxValue = 60000)]     public Int32 ProcessingSleepTime     {         get         {             if (this['ProcessingSleepTime'] == null)                 return 100;              return (Int32)this['ProcessingSleepTime'];         }         set         {             this['ProcessingSleepTime'] = value;         }     } 

If a value in the configuration file fails validation, a ConfigurationErrorsException is thrown. In a windows service this happens as it is trying to start and it’s really ugly (it offers to launch the debugger). How can I gracefully handle this error? I tried wrapping the OnStart method in a try/catch but it had no effect.

Thanks.

Answer 1

Or better yet (as you might need multiple such a properties), using the code from @Ricardo Villiamil, create:

int GetIntFromConfigSetting(string settingName, int defaultValue) {    int retValue = defaultValue;    if(this.ContainsKey(settingName))    {       int sleepInterval;       if(Int32.TryParse(this[settingName], out sleepInterval)       {          retValue = sleepInterval;       }    }    return retValue; } 

Then use it from any property you need to.

EDIT: actually, after re-reading the question once more, looks like this solves your problem only half-way, as if the value is out of the defined range, it will throw exception anyway.

EDIT2: You can hook the AppDomain.UnhandledException event in the static ctor of your config section handler. The static ctor is ran before any instance or static member of a class are accessed, so it guarantees that you will intercept the exception even if the main method of your service is not yet called.

And then, when you intercept and log the error, you can exit the service with some error code != 0 ( Environment.Exit(errorCode) ), so the service manager knows it failed, but not try to invoke a debugger.