Question

I have a webservice project (old asmx technology) in which I have a class User. This class has a DateTime property that represents the birthdate of this user. Beside this class, I have another file with a partial class User. In this partial class, I add a property ‘Age’ which returns the age of the user:

public partial class User
{
    public DateTime Age
    {
        get { return DateTime.Now - this.Birthdate; }
    }
}

The reason that this is in a partial class is because the User class code is automatically generated from a config file, and I cannot add code to this class without it being removed every time the code is generated.

Now in my webservice I have a webmethod that returns a list of these Users which it gets from a database:

[WebMethod]
public List<User> GetUsers()
{
    return Database.LoadUsers();
}

Simple enough… Anyway, in a different project now, I add a Service Reference to this webservice. It generates the service client and a User class for me. The problem is: this User class does not contain the properties defined in the partial class (Age in this example)… It seems the webservice doesn’t get this information.

Of course I can create a new partial User class and basically rewrite it in the second project, but I shouldn’t have to, should I? Why doesn’t the webservice recognize the partial class?

Answer 1

Partial classes are not extension methods. They are compiled together into one class in each assembly. You have two options for what you want to do:

Option 1

Add the partial class you wrote as a link to the new project. It will be the same file, but linked into the new project. When you go to Add -> Existing Item, select the arrow by Open and choose “Add as Link”.

Option 2

Create an extension method:

public static class DateExtensions
{
    public TimeSpan GetAge(this DateTime birthDate)
    {
        return DateTime.Now - birthDate;
    }
}

Then, just add a using statement for whatever namespace your extension class is in, and make sure the project/assembly is referenced, and you can call this:

// This is your BirthDate property that would come back and is DateTime
var birthDate = new SomeService().DoSomething().BirthDate;

var age = birthDate.GetAge();

Option 3

Create a separate project and put the service reference and partial in it. Reference the project (and the necessary framework references) from your using projects.

I have created an example for you to view/use on GitHub.