Invoke .NET Objects Using Flex's RemoteObject

Invocation of a .NET object using the <mx:RemoteObject> MXML declaration can be done in just a few simple steps. This article will guide through the setup and onfiguration:

Download the latest version of WebORB for .NET
Deploy your .NET assembly with the class you will be invoking from Flex into WebORB. This can be done simply by copying the DLL into the /bin folder.
Open WEB-INF\flex\remoting-config.xml in a text editor and add a destination declaring your .NET type. Use the following format:

<destination id="destination-name">
   <properties>
     <source>Your.Net.ClassName</source>
   </properties>
</destination>

destination-name is an id assigned to your .NET class. The id will be used by Flex client when invoking server-side methods
Your.Net.ClassName full name of a .NET type exposed as a service to Flex clients

Create a Flex Builder project as it is described in this article.
Add the following remote object declaration to your MXML's application markup:
```
<mx:RemoteObject id="remote-object-id" destination="destination-name"
                 showbusycursor="true" fault="faultHandler(event)">
    <mx:method name="methodToInvoke" result="successHandler(event)">
</mx:RemoteObject>
```
where,
- destination-name must be the same literal as destination id set in the server-side config
- remote-object-id is an id used in the MXML application to refer to a remote object
- methodToInvoke is the method name available in the remote destination that your remote object can invoke
- successHandler and faultHandler are function references your MXML application will invoke upon successful or unsuccessful method invocation

Suppose the following .NET class needs to be consumed by a Flex client:

namespace weborb.tests
{
   public class HelloWorld
   {
      public string sayHello()
      {
         return "Hey Flex";
      }
   }
}

then the destination declaration may look as the following:

<destination id="helloWorld">
  <properties>
     <source>weborb.tests.HelloWorld</source>
  </properties>
</destination>

The <RemoteObject> declaration would have the following contents:

<mx:RemoteObject id="helloWorldService" destination="helloWorld"
                 showbusycursor="true" fault="faultHandler(event)">
    <mx:method name="sayHello"result="gotHello(event)">
</mx:RemoteObject>

The callback handler functions (gotHello and faultHandler) could be declared as:

private function gotHello(event:ResultEvent):void
{
Alert.show("Server said: " + event.result, "Success");
}

private function faultHandler(event:FaultEvent):void
{
Alert.show(event.fault.faultstring, "Error");
}

Now anywhere in your MXML application you can invoke sayHello using the following line of code: helloWorldService.sayHello();