DisplayAttribute is not public

[fernandolamp]

Hi!

I'm writing an OpenApiOperation extension using enum and I've noticed that it has a method named GetDisplayName to use a display name instead of a enum name.

OpenAPI.NET/src/Microsoft.OpenApi/Extensions/EnumExtensions.cs

Line 40 in 1280e48

public static string GetDisplayName(this Enum enumValue)

        /// <summary>
        /// Gets the enum display name.
        /// </summary>
        /// <param name="enumValue">The enum value.</param>
        /// <returns>
        /// Use <see cref="DisplayAttribute"/> if exists.
        /// Otherwise, use the standard string representation.
        /// </returns>

But, DisplayAttribute is a private attribute and it's not possible to use them.

OpenAPI.NET/src/Microsoft.OpenApi/Attributes/DisplayAttribute.cs

Line 12 in 1280e48

internal class DisplayAttribute : Attribute

Is it possible to change this attribute to be public instead internal class?

Example of use:

   //my enum, used on docOptions
    public enum ApiLevel
    {
        [DisplayAttribute(Name = "private")]
        Privada = 1,
        [Display(Name = "public")]
        Publica = 2,
        [Display(Name = "corporate")]        
        Corporativa = 3
    }

//my filter where i use the enum
    internal class OpenApiExampleFilter : IOperationFilter
    {
        private readonly DocOptions _docOptions;

        public OpenApiExampleFilter (DocOptions docOptions)
        {
            _docOptions = docOptions;
        }

        public void Apply(OpenApiOperation operation, OperationFilterContext context)
        {           
            operation.AddExtension("x-test", new OpenApiObject
            {
                ["apiLevel"] = new OpenApiString(_docOptions.ApiLevel.GetDisplayName()), //here i cant use GetDisplayName() :(
                ["apiDomain"] = new OpenApiString(_docOptions.ApiDomain)
            });
        }
    }

Tks!

[darrelmiller]

That seems like a reasonable request to me.

[CodeCasterNL]

@darrelmiller any reason not to use System.ComponentModel.DataAnnotations.DisplayAttribute but to roll your own?

Perhaps remove it and use the BCL one? This library targets NETStandard 2.0, which covers the existing attribute (.NET Framework 4+, .NET Core 1+).

[fernandolamp]

@darrelmiller any reason not to use System.ComponentModel.DataAnnotations.DisplayAttribufe?

This make sense. I can change if @darrelmiller agrees.

[CodeCasterNL]

On the other hand, one might want to differ between DataAnnotations.Display for MVC purposes, and OpenApi.Attributes.Display for OpenAPI descriptions, I think? Not sure what the intended usage for the attribute is, other than to annotate your classes exposed from your API?

[fernandolamp]

On the other hand, one might want to differ between DataAnnotations.Display for MVC purposes, and OpenApi.Attributes.Display for OpenAPI descriptions, I think? Not sure what the intended usage for the attribute is, other than to annotate your classes exposed from your API?

I was analyzing the code. Display attribute is used to standardize the display name of the enum.

And get enum from display name on StringExtensions

OpenAPI.NET/src/Microsoft.OpenApi/Extensions/StringExtensions.cs

Line 19 in a17303c

public static T GetEnumFromDisplayName<T>(this string displayName)

In my code i'm using to solve the same problem, i need to expose this enums using lower case and translated.

Both attribute is used to the same thing, but to use from System.ComponentModel.DataAnnotations is necessary install the package System.ComponentModel.Annotations.

I don't know if reference this package in this project is a problem. If not, this change make sense and is simple.

I made this change in my local branch and all test have passed, i can push if there is no problem.

[CodeCasterNL]

@MaggieKimani1 or @darrelmiller can you chime in on the discussion? Does the attribute need to exist in the first place? Less code being more and all.

[darrelmiller]

@CodeCasterNL I agree less code is more, and the problem with System.ComponentModel.DataAnnotations is that it pulls in all kinds other code that we don't use and don't support. The DisplayAttribute class is only a few lines of code. I'd rather not take another dependency for just this small feature.

[CodeCasterNL]

@darrelmiller sorry, I meant System.ComponentModel.DisplayNameAttribute all along, which is covered in netstandard2.0. You're right in that referencing the package System.ComponentModel.DataAnnotations would be overkill to remove like ten lines of code.