Question

I am creating an XML web service that passes an array of custom types. In my consuming code I am referencing the code as a web reference which I have given the namespace MYWS. Now in code I am trying to assign the results of my web service call to an array of my type like so :

 'instance to make a call to my web service
 Dim srv As New MYDWS.ServiceNameWSSoapClient
 'array to hold the results                           
 Dim arr() As MyClass
 'assign the web service call results
 arr = srv.myWebMethod()

When I do this the complier complains, saying:

Value of 1 dimensional array of my.namespace.MyClass cannot be
converted to 1 dimensional array of my.namespace.MYWS.MyClass because
my.namespace.MYSW.MyClass is not derived from my.namespace.MyClass

Now I understand the message, the thing is they are the same class. The class is declared in my calling code by the web service references a dll from that project. How do I tell the compiler that these are the same type? Any help would be very much appreciated. Thanks!

Answer 1

The upshot is that you have a namespace mismatch. If you right-click on MyClass in your example and select Go To Definition, where does it take you? I suspect that you may end up in a locally defined class.

The solution is to change

Dim arr() As MyClass

to

Dim arr() As MYWS.MyClass

Update based on information in comments

The problem with using the web service is that you cannot cast it to a local class.

You have a couple of options depending on exactly what you need out of the local class.

If you only need methods to act on the data in the class or you need additional properties, you can create a partial class in your environment that extends the class created by the web service. For example:

Namespace MYWS

    Public Partial Class MyClass

        Public Property SomeAdditionalData As String

        Public Sub SomeMethod
           ' Perform some operations on the class members
        End Sub
    End Class

End Namespace

However, if you have calculations or other work embedded in the class, then you will need to get the data using the web service class, then copy the data from that class into your local class. If the properties have the same names, you could ease this task using reflection.

As another option, if you have control over the web service, you could change it to a WCF service. This will allow you to reuse the exact same class code on both ends of the communication pipe.