openapi-generator/modules/swagger-codegen/src/main/resources/csharp/enumClass.mustache

public enum {{vendorExtensions.plainDatatypeWithEnum}} {
            {{#allowableValues}}{{#enumVars}}
            [EnumMember(Value = "{{jsonname}}")]
            {{name}}{{^-last}},
            {{/-last}}{{#-last}}{{/-last}}{{/enumVars}}{{/allowableValues}}
        }