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c#asp.net-coreasp.net-core-2.2

Is there any alternates Attribute for asp.net core enum model binding instead of EnumMemberAttribute?


There's a enum type:

public enum Cat {
    [EnumMember(Value = "white_cat")]
    WhiteCat,
    [EnumMember(Value = "black_cat")]
    BlackCat
}

but use as follow asp.net core 2.2 model binding, it will binding failure:

public class A {
    public Cat TheCat { get; set; }
}

public class XXXController : ControllerBase {
    public ActionResult XXX([FromForm] Cat cat) {
        // ...
    }
}

Solution

  • Reference: https://stackoverflow.com/a/58338955/3907561

    public class EnumMemberConverter<T> : EnumConverter {
        public EnumMemberConverter(Type type) : base(type) { }
    
        public override object ConvertFrom(ITypeDescriptorContext context, 
                                           CultureInfo culture, 
                                           object value) {
            var type = typeof(T);
    
            foreach (var field in type.GetFields()) {
                if (Attribute.GetCustomAttribute(field, typeof(EnumMemberAttribute)) is EnumMemberAttribute attribute &&
                    value is string enumValue &&
                    attribute.Value == enumValue) {
                    return field.GetValue(null);
                }
            }
    
            return base.ConvertFrom(context, culture, value);
        }
    }
    
    

    usage:

    [TypeConverter(typeof(EnumMemberConverter<Cat>))]
    public enum Cat {
        [EnumMember(Value = "white_cat")]
        WhiteCat,
        [EnumMember(Value = "black_cat")]
        BlackCat
    }