Webservices, Class Libraries, and Syncronizing Namespaces

[Jon Ebersole]

I am developing a webservice and a windows application that talk to each
other. They are using a standard VB class library in the background. I am
having problems understanding why I can't sync my namespaces properly.
Example;

My Windows namespace is MyCompany.MyWin dowsSpace
My Webservice namespace is MyCompany.MyWeb Service
My Class Library namespace is MyCompany.MyLib rary

I am using typed objects to send back and forth to my webservice. In my
webservice code-behind page I Have a function that looks like this...

<System.Web.Ser vices.WebServic e(Namespace:="M yCompany.MyLibr ary")_
<System.Web.Ser vices.WebServic eBinding(Confor msTo:=WsiProfil es.BasicProfile 1_1)_
<ToolboxItem(Fa lse)_
Public Class MyWebService
Inherits System.Web.Serv ices.WebService

<WebMethod()_
Public Function HelloWorld(ByVa l MyString As MyCompany.MyLib rary.String)
As MyCompany.MyLib rary.String
Return MyString
End Function

End Class
I register my web reference with my windows application and it asks for a
name. I give it MyWebService as the name. Then, in my code, I use the
following to access the the item and use the webservice...

Protected Friend oWebService As New MyCompany.MyWin dowsSpace.MyWeb Service
Dim oMyString as new MyCompany.MyLib rary.MyString
oMyString.Value = "Hello"
dim oMyStringResult as new MyCompany.MyLib rary.MyString
oMyStringResult = oWebService.Hel loWorld(oMyStri ng)

When I compile the code from above, I get the following error message.
Value of type 'MyCompany.MyLi brary.MyString' cannot be converted to
'MyCompany.MyWe bService.MyStri ng'. on the actual line that calls HelloWorld.

I found a work-around, but I hate doing it, because everytime I make changes
to the web service, I have to go back to the file mentioned below and make
the changes again. I can select to show all files in my web project, then
navigate under web references to the MyWebService's Reference.map.v b file and
change the following code from...
<System.Web.Ser vices.Protocols .SoapDocumentMe thodAttribute(" MyCompany.Libra ry/HelloWorld",
RequestNamespac e:="MyCompany.L ibrary",
ResponseNamespa ce:="MyCompany. Library",
Use:=System.Web .Services.Descr iption.SoapBind ingUse.Literal,
ParameterStyle: =System.Web.Ser vices.Protocols .SoapParameterS tyle.Wrapped) _
Public Function HellowWorld(ByV al oMyString As MyString) As MyString
Dim results() As Object = Me.Invoke("Hell oWorld", New Object()
{oMyString})
Return CType(results(0 ),MyString)
End Function

to...
<System.Web.Ser vices.Protocols .SoapDocumentMe thodAttribute(" MyCompany.Libra ry/HelloWorld",
RequestNamespac e:="MyCompany.L ibrary",
ResponseNamespa ce:="MyCompany. Library",
Use:=System.Web .Services.Descr iption.SoapBind ingUse.Literal,
ParameterStyle: =System.Web.Ser vices.Protocols .SoapParameterS tyle.Wrapped) _
Public Function HellowWorld(ByV al oMyString As
MyCompany.MyLib rary.MyString) As MyCompany.MyLib rary.MyString
Dim results() As Object = Me.Invoke("Hell oWorld", New Object()
{oMyString})
Return CType(results(0 ),MyCompany.MyL ibrary.MyString )
End Function

It forces my object types and allows me to compile it, because they now
match. Does anyone know how to do this the right way? Thanks for your help.
--
Jon Ebersole
Microsoft Certified Solution Developer

[Steven Cheng[MSFT]]

Hello Jon,

From your description, you've developed an ASP.NET webservice which is
consumed by your winform client application, however, you found that when
generating the webservice client proxy, the classes's namespace doesn't
match the one defined in your webservice project, correct?

As for this issue, it is actually due to XML Webservice's natural design
which is used to connect distributed heterogenous platform/system. Thus,
the client-side webservice consumer(applic ation) should not have sense of
how the server-side webservice is implemented. For example, the client
winform application can add webreference against a certain webservice, and
it will generate client proxy class and other helper classes which will be
used to map the XML WebService's SOAP request/response message and content.
However, client application doesn't need to know how the server webservice
is implemented.(It could be implemented by ASP.NET webservice, or java
webservice or a normal XSLT translator service...)

For your scenario, if you do want to make your webservice's client-side
proxy class use the existing component classes(in a separate class
library), you can consider the following means:

1. Manually modify the auto-generated Reference.cs file. As you have found,
it is a bit inconvenient since the IDE will regenerate the code and
override our modification when updating the proxy. To avoid this, you can
consider use the wsdl.exe to manually create the proxy class externally and
use it in your project:

#Web Services Description Language Tool (Wsdl.exe)
http://msdn2.microsoft.com/en-us/library/7h3ystb6.aspx
2. In .net 2.0, there is a new compilation feature called partial class,
you will find that autogenerated webservice's proxy class is a partial
class. Thus, you can add your modification on the proxy class into another
partial class file (only contains the webservice method that use your own
class)
e.g.
suppose the autogenerated proxy class is as below:
======Reference .cs========
namespace TestClient.Simp leService {
............... .....
[System.CodeDom. Compiler.Genera tedCodeAttribut e("System.Web.S ervices",
"2.0.50727. 42")]
[System.Diagnost ics.DebuggerSte pThroughAttribu te()]
[System.Componen tModel.Designer CategoryAttribu te("code")]

[System.Web.Serv ices.WebService BindingAttribut e(Name="SimpleS erviceSoap",
Namespace="http ://tempuri.org/")]
public partial class SimpleService :
System.Web.Serv ices.Protocols. SoapHttpClientP rotocol {
............... ............... .........
[System.Web.Serv ices.Protocols. SoapDocumentMet hodAttribute(". ...............
............)]
public SimpleClass GetSimpleClassO bject(long id, string name) {
object[] results = this.Invoke("Ge tSimpleClassObj ect", new
object[] {
id,
name});
return ((SimpleClass)( results[0]));
}

}

You can add a new partial class file for the proxy class and add your own
webmethod function, like

#instead of using the "SimpleClas s", I use "MySimpleClass" (defined in
classlibrary)
=======Referenc e.custom.cs==== =============== =====

namespace TestClient.Simp leService
{
............... .....

public partial class SimpleService
{

[System.Web.Serv ices.Protocols. SoapDocumentMet hodAttribute(.. ...............
............... .)]
public MySimpleClass MyGetSimpleClas sObject(long id, string name)
{
object[] results = this.Invoke("Ge tSimpleClassObj ect", new
object[] {
id,
name});
return ((MySimpleClass )(results[0]));
}

}

=============== ========

Thus, the customization code in partial class file won't be modified when
you update proxy class. Here is the reference about partial class in MSDN:

#Partial Class Definitions (C# Programming Guide)
http://msdn2.microsoft.com/en-us/library/wa80x488.aspx

Just some of my opinions on this, hope helps some. If you have any further
questions on this, please feel free to let me know.

Sincerely,

Steven Cheng

Microsoft MSDN Online Support Lead

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