im calling an actionscript class from my main mxml file. the actionscript class is responsible for calling a web service and handling the response, however im having trouble and keep getting the following error; (im new to flex btw)
Error #1009: Cannot access a property or method of a null object reference.
my code goes as follows;
public function getSites(argWsdl:String):void{
ws = new WebService();
ws.loadWSDL(argWsdl);
ws.getSites.addEventListener(ResultEvent.RESULT,echoResultHandler);
ws.getSites();
}
public function echoResultHandler(event:ResultEvent):void {
var siteField:ArrayCollection = event.result as ArrayCollection;
Application.application.setSiteField(siteField);
}
when i run the debugger the code never reaches the result hanlder and i see the #1009 error in the variable list.
any ideas?
looks like you have it sorted, but just to add more information in case someone else comes along to this question, you generally see this error when you are trying to use something that hasn't been created yet. A lot of the time you will see it when trying to access UI components that have not yet been created (its good to rely on the creationComplete event for these sort of things), but in this case it looks like you are using the webservice before it is completely ready (the wsdl hasnt been loaded yet).
Just so you know, you can also define your webservices in mxml (mx:webservice) and specify the wsdl there or you can also load the wsdl later on from a configuration file afterwards just by referencing the ID.
sorted it out,
i needed to created a loadEvent and loadhandler. Once loadWsdl is called the loadhandler specifies the laodHandler to use, inside the loadHandler i call the method name as seen in the wsdl
thanks Ryan,
the main reason im using a seperate actionscript class is so i can reuse the same web service calls across my components without having to retype the same code. I couldnt think of a better way to do this - maybe a could have done the same with a custom component
Related
I use java to call the Rhino javascript, and it works.
in the javascript file, I define the following javascript object
var person = {firstName:"John", lastName:"Doe", age:50, eyeColor:"blue"};
then trying to access object by:
print(JSON.stringify(person))
and I got a error has no public instance field or method named "toJSON".
I am confused, the way the person gets defined it is definitly a JS object. how come this runtime thinks its still a Java object
Take a look at issue in the Rhino GitHub , also linking PR that still open
Think of the following:
I've got a table data grid webcomponent and another component providing a data feed. In the applications main acting as kind of controller, i'd like to wire and setup those two components. Therefore i need a reference to underlying table grid instance Dart class and call methods on the "Component API' (to provide the table grid's tablemodel with data).
How do I access the Dart Class instance of a webcomponent instance from outside ?
Probably I missed something fundamental or are polymer webcomponents meant to interact only using databinding and stringy attributes stuff ?
Follow up: Found it !!
RLTable table = querySelector("#apptable").xtag;
does the job
As zoechi pointed out, xtag is not necessary.
var component = $['myComp'];
var componentXtag = $['myComp'].xtag;
print(component == componentXtag);
prints true. Therefore both
component.method()
componentXtag.method()
work fine
You don't need xtag. Some weeks/months ago this was a workaround until the final solution was landed.
I have an application using the Entity Framework code first. My setup is that I have a core service which all other services inherit from. The core service contains the following code:
public static DatabaseContext db = new DatabaseContext();
public CoreService()
{
db.Database.Initialize(force: false);
}
Then, another class will inherit from CoreService and when it needs to query the database will just run some code such as:
db.Products.Where(blah => blah.IsEnabled);
However, I seem to be getting conflicting stories as to which is best.
Some people advise NOT to do what I'm doing.
Other people say that you should define the context for each class (rather than use a base class to instantiate it)
Others say that for EVERY database call, I should wrap it in a using block. I've never seen this in any of the examples from Microsoft.
Can anyone clarify?
I'm currently at a point where refactoring is possible and quite quick, so I'd like some general advice if possible.
You should wrap one context per web request. Hold it open for as long as you need it, then get rid of it when you are finished. That's what the using is for.
Do NOT wrap up your context in a Singleton. That is not a good idea.
If you are working with clients like WinForms then I think you would wrap the context around each form but that's not my area.
Also, make sure you know when you are going to be actually executing against your datasource so you don't end up enumerating multiple times when you might only need to do so once to work with the results.
Lastly, you have seen this practice from MS as lots of the ADO stuff supports being wrapped in a using but hardly anyone realises this.
I suggest to use design principle "prefer composition over inheritance".
You can have the reference of the database context in your base class.
Implement a singleton for getting the DataContext and assign the datacontext to this reference.
The conflicts you get are not related to sharing the context between classes but are caused by the static declaration of your context. If you make the context an instance field of your service class, so that every service instance gets its own context, there should be no issues.
The using pattern you mention is not required but instead you should make sure that context.Dispose() is called at the service disposal.
I would like to do coloring in Eclipse without using the presentation reconciler. Therefore, first, I need to figure out how to associate a TextPresentation object with either my editor or document, but I am having difficulty finding out how to link it either of those. Normally, the CreatePresentation in the IPResentationReconciler interface would give the style range to the textpresentation, and from there Eclipse would know what to do with that presentation object. Is there some way to use a TextPresentation object without the use of PresentationReconciler? It would be nice if I could do coloring without the use of reconciler. Thank you.
I finally figured out how to achieve the coloring without the use of Reconcilers.
I discovered that first I needed a way to obtain a reference to my SourceViewer object, as I am extending TextEditor. I also discovered that I could implement the TextListener interface and add my own listener to the SourceViewer object. One must be careful, however, as calling the getSourceViewer() method can result in null if not called at the appropriate spot. Originally, I overwrote the init(...) function in my editor class and made the getSourceViewer() call, but it still resulted in null. After doing a bit of research, I discovered that I could properly obtain a reference to the SourceViewer object by overriding the createPartControl method. I first call super.createPartControl(...) and then make a call to getSourceViewer(). After I obtained that reference, I used that with my listener class I created and was able to do the coloring myself with the setTextColor method the SourceViewer object has. Hope this helps others in the same situation.
I'm currently working on a project with symfony 1.4 and Doctrine 1.2. I'm looking for a proper way to do logging from the model layer.
In some model classes I use the record hook postSave() to create a ZIP file using exec() (since PHP zip doesn't provide for storage method 'Stored'). To be sure that everythings works fine I check the return code and log an error if something goes wrong. My first naive approach was to do it like this:
if ($returnCode != 0) {
sfContext::getInstance()->getLogger()->debug(...);
}
As you know, this doesn't work so well because sfContext belongs to the controller layer and shouldn't be used from the model layer. My next try was to use the model's constructor to pass in an sfLogger instance, but this doesn't work due to Doctrine 1.2 reserving the constructor for internal use (Doctrine 1.2 Documentation).
I'm looking forward for your suggestions!
You can add a setLogger() method to your function, that gets a logger instance in a parameter, and sets it to an internal variable, like $this->logger. Later, when you need to log something, do it like if ($this->logger) { $this->logger->debug(...); }.