Is it possible to have two partial classes in different assemblies represent the same class?

Question

I have a class called \'Article\' in a project called \'MyProject.Data\', which acts as the data layer for my web application.

I have a separate project called \'MyP

Answer 1

Extension methods and ViewModels are the standard way to extend data-layer objects in the frontend like this:

Data Layer (class library, Person.cs):

namespace MyProject.Data.BusinessObjects
{
  public class Person
  {
    public string Name {get; set;}
    public string Surname {get; set;}
    public string Details {get; set;}
  }
}

Display Layer (web application) PersonExtensions.cs:

using Data.BusinessObjects
namespace MyProject.Admin.Extensions
{
  public static class PersonExtensions
  {
    public static HtmlString GetFormattedName(this Person person)
    {
       return new HtmlString(person.Name + " <b>" + person.Surname</b>);
    }
  }
}

ViewModel (for extended view-specific data):

using Data.BusinessObjects
namespace MyProject.Admin.ViewModels
{
  public static class PersonViewModel
  {
    public Person Data {get; set;}
    public Dictionary<string,string> MetaData {get; set;}

    [UIHint("FCKeditor")]
    public object PersonDetails { get { return Data.Details; } set {Data.Details = value;} }
  }
}

Controller PersonController.cs:

public ActionMethod Person(int id)
{
  var model = new PersonViewModel();
  model.Data = MyDataProvider.GetPersonById(id);
  model.MetaData = MyDataProvider.GetPersonMetaData(id);

  return View(model);
}

View, Person.cshtml:

@using MyProject.Admin.Extensions

<h1>@Model.Data.GetFormattedName()</h1>
<img src="~/Images/People/image_@(Model.MetaData["image"]).png" >
<ul>
  <li>@Model.MetaData["comments"]</li>
  <li>@Model.MetaData["employer_comments"]</li>
</ul>
@Html.EditorFor(m => m.PersonDetails)

Answer 2

Just add class file as link in your new project and keep the same namespace in your partial class.

Answer 3

No, you cannot have two partial classes referring to the same class in two different assemblies (projects). Once the assembly is compiled, the meta-data is baked in, and your classes are no longer partial. Partial classes allows you to split the definition of the same class into two files.

Answer 4

I may be mistaken here, but could you not simply define the ProjectMetaData class in your MyProject.Admin project?

Answer 5

Perhaps use a static extension class.

Answer 6

Since 2019 you can have 2 parts of a partial class in different assemblies using a trick. This trick is explained and demonstrated in this article:

https://www.notion.so/vapolia/Secret-feature-Xamarin-Forms-control-s-auto-registration-1fd6f1b0d98d4aabb2defa0eb14961fa

It uses at its core the MSBuild.Sdk.Extras extension to SDK like projects, which solves the limitation of having all partial parts of a class in the same assembly, by using one project with multiple simultaneous targets, effectively creating multiples assemblies in one compilation of the same project.