Use DisplayAttribute methods when getting name and description

[wazzamatazz]

Related to #1145.

DisplayAttribute has GetName and GetDescription methods that will return the Name and Description property values respectively if no ResourceType has been specified on the attribute, or will look up resource values if a ResourceType has been specified.

This PR updates schema generation to use the above methods when a DisplayAttribute is used, which allows localised resources to be used when generating schemas in addition to hard-coded name and description values.

[RicoSuter]

Is using GetName() a breaking change from what we had before?
Maybe we should add a null check here as well (as before) as title might already be set and gets resetted to null otherwise.

[wazzamatazz]

GetName() will return the value of the Name field if the ResourceType property on the DisplayAttribute is null, so in this circumstance, the behaviour is the same.

If a ResourceType property is specified on the DisplayAttribute, then GetName() will retrieve the value from the ResourceType instead e.g.

public class MyClass {
  // No ResourceType specified: DisplayAttribute.GetName() returns "Some_Property"
  [Display(Name = "Some_Property")]
  public string SomeProperty { get; set; }
}


public class MyOtherClass {
  // ResourceType specified: DisplayAttribute.GetName() returns MyResources.Some_Property
  [Display(ResourceType = typeof(MyResources), Name = "Some_Property")]
  public string SomeProperty { get; set; }
}

Current behaviour does not have a check to see if the title has already been set.

[wazzamatazz]

Committed a check to ensure that the Name property is not null before calling GetName()

[RicoSuter]

Instead of a .Name check and know the internals of GetName() I think it would be better to do:

if (displayAttribute != null)
{
     var name = displayAttribute.GetName();
     if (name != null)
     {
         schema.Title = name;
     }
}

this way we only use GetName() and not assume a correlation between Name and GetName() (same for description)

[wazzamatazz]

Okay, will do.

[wazzamatazz]

Done: 3aa50c8

[RicoSuter]

Is using GetDescription() a breaking change from what we had before?

[wazzamatazz]

GetDescription() will return the value of the Description field if the ResourceType property on the DisplayAttribute is null, so in this circumstance, the behaviour is the same.

If a ResourceType property is specified on the DisplayAttribute, then GetDescription() will retrieve the value from the ResourceType instead which is the intended behaviour of this change e.g.

public class MyClass {
  // No ResourceType specified: DisplayAttribute.GetDescription() returns "Some_Property_Desc"
  [Display(Description = "Some_Property_Desc")]
  public string SomeProperty { get; set; }
}


public class MyOtherClass {
  // ResourceType specified: DisplayAttribute.GetDescription() returns MyResources.Some_Property_Desc
  [Display(ResourceType = typeof(MyResources), Name = "Some_Property_Desc")]
  public string SomeProperty { get; set; }
}

[wazzamatazz]

Committed a check to ensure that the Description property is not null before calling GetDescription()

[RicoSuter]

Thx lgtm