Hi Viv,

I'm not exactly sure if I'm going in the right direction. Here is what I wrote so far:

API Code

[Route("checkCodeUniqueness")]
        [HttpPut]
        public IHttpActionResult CheckCodeUniqueness(UniquenessTestViewModel testModel)
        {
            UniquenessTest model = AutoMapperConfig.Mapper.Map<UniquenessTest>(testModel);
            String errorMessage = _itemAdapter.CheckCodeUniqueness(model);

            testModel.ErrorMessage = errorMessage;
            testModel.IsValid = String.IsNullOrEmpty(errorMessage);

            return Ok(testModel);
        }

Is it right or I should somehow throw an error? And if yes, what should it be?

And for the directive I wrote:

(function (angular) {
    "use strict";

    var services,
        $log,
        resourceFactory;

    angular.module("sysMgrApp").directive("smCodeUniqueValidator", ["ServiceLoader", smCodeUniqueValidator]);

    /**
     * smCodeUniqueValidator Directive
     * @param {} serviceLoader 
     * @returns {Object} 
     */
    function smCodeUniqueValidator(serviceLoader) {
        services = serviceLoader;
        $log = services.Log.getInstance("smCodeUniqueValidator");
        resourceFactory = services.Resource;

        return {
            restrict: "E",
            require: "ngModel",
            
            scope: {
                primaryKey: "=?",
                tableName: "=?",
                columnToTest: "=?"
            },

            link: function ($scope, element, attrs, ngModel) {
                $log.debug("Link is firing...");
                ngModel.$asyncValidators.codeUnique = function (value) {
                    var codeObject = {
                        id: $scope.primaryKey, tableName: $scope.tableName,
                                        columnToTest: $scope.columnToTest, code: value
                    };
                    return services.Item.checkCodeUniqueness(codeObject);
                };
            }
        };
    }
})(angular);

In my form I added

<div class="col-xs-6">
            <div class="controls">
                <label class="control-label"
                       ng-hide="editRetailTrackingForm.barcode.$error.maxlength && editRetailTrackingForm.barcode.$dirty">
                    @Labels.barcode:
                </label>
                <label class="field-validation-error control-label-error animate-show"
                       ng-show="editRetailTrackingForm.barcode.$error.maxlength && editRetailTrackingForm.barcode.$dirty">
                    @String.Format(Messages.cannotExceed, Labels.barcode, "100")
                </label>
                <div ng-class="{loading:editRetailTrackingForm.barcode.$pending}">
                <input type="text" name="barcode"
                       ng-model="currentItem.barcode"
                       sm-code-unique-validator
                       table-name="items"
                       column-to-test="barcode"
                       primary-key="{{currentItem.itemId}}"
                       ng-model-options="{ debounce: { default : 500, blur: 0 }}"
                       class="form-control"
                       ng-maxlength="100" />
                    </div>
            </div>
        </div>

and then I tried to debug in VS 2017 but nothing happened at all. My validation code is not firing. Do you see what may be wrong? I did add the js file in the bundle.config.