Catel.MVVM.ViewModelBase.OnValidatingBusinessRules C# (CSharp) Method

        protected override void OnValidatingBusinessRules(IValidationContext validationContext)
        {
            base.OnValidatingBusinessRules(validationContext);

            lock (_modelLock)
            {
                foreach (var modelObject in _modelObjects)
                {
                    // IDataErrorInfo
                    var dataErrorInfo = modelObject.Value as IDataErrorInfo;
                    if ((dataErrorInfo != null) && !string.IsNullOrEmpty(dataErrorInfo.Error))
                    {
                        validationContext.AddBusinessRuleValidationResult(BusinessRuleValidationResult.CreateError(dataErrorInfo.Error));
                    }

                    // IDataWarningInfo
                    var dataWarningInfo = modelObject.Value as IDataWarningInfo;
                    if ((dataWarningInfo != null) && !string.IsNullOrEmpty(dataWarningInfo.Warning))
                    {
                        validationContext.AddBusinessRuleValidationResult(BusinessRuleValidationResult.CreateWarning(dataWarningInfo.Warning));
                    }

                    // INotifyDataErrorInfo & INotifyDataWarningInfo
                    if (_modelErrorInfo.ContainsKey(modelObject.Key))
                    {
                        var modelErrorInfo = _modelErrorInfo[modelObject.Key];

                        foreach (var error in modelErrorInfo.GetErrors(string.Empty))
                        {
                            validationContext.AddBusinessRuleValidationResult(BusinessRuleValidationResult.CreateError(error));
                        }

                        foreach (var warning in modelErrorInfo.GetWarnings(string.Empty))
                        {
                            validationContext.AddBusinessRuleValidationResult(BusinessRuleValidationResult.CreateWarning(warning));
                        }
                    }
                }
            }
        }