Model-bind interface property with Web API

Question

I have a command looking like:

public interface ICommand {
    // Just a marker interface
}

public interface IUserAware {
    Guid UserId { get; set; }
}

p         


        

Answer 1

public class CreateSomethingModelBinder : IModelBinder
{
    public object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext)
    {
        string key = bindingContext.ModelName;
        ValueProviderResult val = bindingContext.ValueProvider.GetValue(key);
        if (val != null)
        {
            string s = val.AttemptedValue as string;
            if (s != null)
            {
                return new CreateSomething(){Title = s; UserId = new Guid(ControllerContext.HttpContext.Request.Headers["userId"]);}
            }
        }
        return null;
    }
}

and add attribute on the type declaration

[ModelBinder(typeof(CreateSomethingModelBinder))]
public class CreateSomething  { ... }