How to return "interfaces " from a webservice?

[Peter K]

Hi

I am having trouble writing a webservice which is to provide access to
the functions of an existing codebase. The existing code may not be
changed at all.

For example, I obtain an IDataProvider from a factory. IDataProvider has
a method "GetCustome r()" which returns an ICustomer object (ICustomer is
an interface, and at the level of my code I do not know the concrete
implementation) .

Simplified versions of the interfaces:

public interface IDataProvider
{
ICustomer GetCustomer(int id);
}

public interface ICustomer
{
int Id { get; }
string Name { get; set; }
IProject[] Projects { get; set; }
}

public interface IProject : ITask
{
string Name { get; set; }
string Description { get; set; }
}

public interface ITask
{
string Code { get; }
DateTime StartDate { get; set; }
DateTime EndDate { get; set; }
}
But I cannot simply make a webservice which returns an "ICustomer" . I
must have a concrete implementation of ICustomer. Does this mean I need
to write my own concrete implementations of the objects I get from
IDataProvider.G etCustomer(), and copy the data into my new objects?

Thanks,
Peter

[John Saunders [MVP]]

"Peter K" <xd****@hotmail .comwrote in message
news:O3******** ******@TK2MSFTN GP02.phx.gbl...

Hi

I am having trouble writing a webservice which is to provide access to
the functions of an existing codebase. The existing code may not be
changed at all.

For example, I obtain an IDataProvider from a factory. IDataProvider has
a method "GetCustome r()" which returns an ICustomer object (ICustomer is
an interface, and at the level of my code I do not know the concrete
implementation) .

Simplified versions of the interfaces:

public interface IDataProvider
{
ICustomer GetCustomer(int id);
}

public interface ICustomer
{
int Id { get; }
string Name { get; set; }
IProject[] Projects { get; set; }
}

public interface IProject : ITask
{
string Name { get; set; }
string Description { get; set; }
}

public interface ITask
{
string Code { get; }
DateTime StartDate { get; set; }
DateTime EndDate { get; set; }
}
But I cannot simply make a webservice which returns an "ICustomer" . I
must have a concrete implementation of ICustomer. Does this mean I need
to write my own concrete implementations of the objects I get from
IDataProvider.G etCustomer(), and copy the data into my new objects?

That would be one way to do it, but no, you can't return an interface from a
web service.
--
John Saunders [MVP]

[Peter K]

"John Saunders [MVP]" <john.saunder s at trizetto.comwro te in
news:ex******** ******@TK2MSFTN GP06.phx.gbl:

"Peter K" <xd****@hotmail .comwrote in message
news:O3******** ******@TK2MSFTN GP02.phx.gbl...

><snip>
But I cannot simply make a webservice which returns an "ICustomer" . I
must have a concrete implementation of ICustomer. Does this mean I
need to write my own concrete implementations of the objects I get
from IDataProvider.G etCustomer(), and copy the data into my new
objects?

That would be one way to do it, but no, you can't return an interface
from a web service.

Thanks for the confirmation. When you write that "that would be one way to
do it", do you have suggestions of other (better?) ways of doing it?

Thanks,
Peter

[John Saunders [MVP]]

"Peter K" <xd****@hotmail .comwrote in message
news:%2******** ********@TK2MSF TNGP04.phx.gbl. ..

"John Saunders [MVP]" <john.saunder s at trizetto.comwro te in
news:ex******** ******@TK2MSFTN GP06.phx.gbl:

>"Peter K" <xd****@hotmail .comwrote in message
news:O3******* *******@TK2MSFT NGP02.phx.gbl.. .

>><snip>
But I cannot simply make a webservice which returns an "ICustomer" . I
must have a concrete implementation of ICustomer. Does this mean I
need to write my own concrete implementations of the objects I get
from IDataProvider.G etCustomer(), and copy the data into my new
objects?

That would be one way to do it, but no, you can't return an interface
from a web service.

Thanks for the confirmation. When you write that "that would be one way to
do it", do you have suggestions of other (better?) ways of doing it?

Sorry, I've never given it any thought. I've never tried to return
interfaces because I know it doesn't make sense.
--
John Saunders [MVP]