Validation of IDataErrorInfo for properties representing arrays bool []

Question

There are many different types of controls in the WPF window. More specifically: a questionnaire of 25 questions, in each of which there are 10-12 options reflected by RadioButtons or Checkboxes, plus 2-3 additional TextBox controls for each question.

Due to the huge amount of bool properties, they are not bound to separate bool, but to bool [] arrays. Textboxes, of course, are tied to ordinary string properties. For example (removed styles and coordinates from markup as irrelevant):

<RadioButton IsChecked="{Binding RelationTypeMap[0], ValidatesOnDataErrors=True, UpdateSourceTrigger=PropertyChanged}"> <RadioButton.Content> <TextBlock Text="муж, жена" /> </RadioButton.Content> </RadioButton> // ... и так далее .... <RadioButton IsChecked="{Binding RelationTypeMap[10], Mode=TwoWay, ValidatesOnDataErrors=True, UpdateSourceTrigger=PropertyChanged}"> <RadioButton.Content> <TextBlock Text="не родственник" /> </RadioButton.Content> </RadioButton> // ... а вот TextBox <TextBox Text="{Binding RelationOther, Mode=TwoWay, ValidatesOnDataErrors=True, UpdateSourceTrigger=PropertyChanged}"/>

IMPORTANT: Under the terms of the task, all controls should be open. I can not prohibit entering additional fields depending on the state of the checkboxes.

It was necessary to create a system of validation, which will paint with red erroneous logical relations, of which the heap is possible. For example, if the tick "not relative" is ticked, then paint the RelationOther field with red if it is not empty.

There are also logical relationships between different issues. For example, if question 2 (two RadioButtons are “gender”) is “male” (not female), then any filling in the following 4 questions is red (questions for women only).

I decided to use a validation system based on IDataErrorInfo, as a native for WPF. Markup that refers to a validation that "ignites" the validation event is visible above. And here is the ViewModel fragment:

 public class FormLViewModel : QuestionnairesBaseViewModel, IQuestionnaireViewModel, IDataErrorInfo { // ... #region Валидация public string this[string columnName] { get { string error = String.Empty; switch (columnName) { case "RelationOther": if (!string.IsNullOrEmpty(RelationOther) && RelationTypeMap.Any(x => x == true) && !RelationTypeMap[10]) error = "Ошибка! Указание описания не требуется"; break; case "MarriageFaceNum": if ((MarriageFaceNum ?? 0) > 0 && MarriageStateMap.Any(x => x == true) && !(MarriageStateMap[0] || MarriageStateMap[1])) error = "Ошибка! Указание номера супруга не требуется"; break; case "ChildsNum": if ((ChildsNum ?? 0) > 0 && (SexMap[0] || FullOld < 15)) error = "Ошибка! Количество детей указывают только женщины от 15 лет и старше"; break; case "ChildBirthDate": if ((ChildBirthDate ?? default) != default && (SexMap[0] || FullOld < 15) && (ChildsNum ?? 0) > 0) error = "Ошибка! Дату рождения первого ребенка указывают только женщины от 15 лет и старше, имеющие детей"; break; case "Nationality": if (NoNationality && !string.IsNullOrEmpty(Nationality)) error = "Ошибка! Не требуется указывать национальность при отказе от ответа"; break; case "MoneySourcesOther": if (!string.IsNullOrEmpty(MoneySourcesOther) && MoneySourceMap.Any(x => x == true) && !MoneySourceMap[11]) error = "Ошибка! Не требуется вводить иной источник дохода"; break; case "JobPlacementRegion": if (JobPlacementMap[0] && !string.IsNullOrEmpty(JobPlacementRegion)) error = "Ошибка! Не нужно указывать расположение Вашей работы, если ответили \"Да\" в вопросе выше"; break; case "JobPlacementTown": if (JobPlacementMap[0] && !string.IsNullOrEmpty(JobPlacementTown)) error = "Ошибка! Не нужно указывать расположение Вашей работы, если ответили \"Да\" в вопросе выше"; break; case "JobPlacementForeign": if (JobPlacementMap[0] && !string.IsNullOrEmpty(JobPlacementForeign)) error = "Ошибка! Не нужно указывать расположение Вашей работы, если ответили \"Да\" в вопросе выше"; break; case "JobPlacementDistrict": if (JobPlacementMap[0] && !string.IsNullOrEmpty(JobPlacementDistrict)) error = "Ошибка! Не нужно указывать расположение Вашей работы, если ответили \"Да\" в вопросе выше"; break; case "JobSearchReasonOther": if (!string.IsNullOrEmpty(JobSearchReasonOther) && JobSearchReasonMap.Any(x => x == true) && !JobSearchReasonMap[9]) error = "Ошибка! Указание иной причины не требуется"; break; case "ResidenceFromYear": if (ResidenceFromBirth && (ResidenceFromYear ?? 0) > 0) error = "Ошибка! Не нужно указывать год прибытия, если Вы живете здесь с рождения"; break; case "ResidenceFromMonth": if (ResidenceFromBirth && (ResidenceFromMonth ?? 0) > 0) error = "Ошибка! Не нужно указывать год и месяц прибытия, если Вы живете здесь с рождения"; break; case "PreviousResidence": if (ResidenceFromBirth && !string.IsNullOrEmpty(PreviousResidence)) error = "Ошибка! Не нужно указывать прежнее место жительства, если Вы живете здесь с рождения"; break; case "ForeignResidenceCountry": if (!string.IsNullOrEmpty(ForeignResidenceCountry) && ForeignResidenceMap.Any(x => x == true) && !ForeignResidenceMap[0]) error = "Ошибка! Не нужно указывать страну проживания, если ответили \"Нет\" в вопросе выше"; break; case "ReturnYear": if ((ReturnYear ?? 0) > 0 && ForeignResidenceMap.Any(x => x == true) && !ForeignResidenceMap[0]) error = "Ошибка! Не нужно указывать год возвращения, если ответили \"Нет\" в вопросе выше"; break; case "RegistrationPlaceOther": if (!string.IsNullOrEmpty(RegistrationPlaceOther) && RegistrationPlaceMap.Any(x => x == true) && !RegistrationPlaceMap[2]) error = "Ошибка! Не нужно указывать наименование"; break; } if (!string.IsNullOrEmpty(error)) _withErrors = true; return error; } } public string Error => string.Empty; // ... }

PROBLEM: Any changes in controls such as TextBox, SpinEdit (DevExpress), etc., in short, that are not mapped to bool [] arrays, lead to a call to the indexer, in which I can analyze the current situation and swear on the field if necessary . However, any changes in the state of checkboxes (arrays bool []) do not trigger the event to fire, we do not get into the indexer, and nothing works.

As a result: if you first tick, and then fill in TextBoxes, validation occurs, but if you first fill in TextBoxes, and then create invalidations with ticks, no errors.

I have already been written here an example of how to solve a problem through a surrogate field, where each tick merges its value. I reproduced the example - it works. But in the example, all bool's fields are single. I tried to make them arrays, like mine, and the example stopped working.

Unfortunately, it is necessary to correct the validation quickly, crutches are allowed. Expanding all arrays into single fields is not an option. There will be more than 200. Too much for the properties of the ViewModel. Help me find a quick fix, please! You can even on crutches!

Andrey Kutasevich Andrey Kutasevich 43 five · Accepted Answer · 2018-10-02T14:42:06

Detailed response at the request of the participant.

I had a binding to bool [] in XAML. When switching to ObservableCollection, the binding did not change at all. That is, I did not touch View at all!

Here is the binding in XAML was and remains:

 <RadioButton IsChecked="{Binding RelationTypeMap[0]}"> <RadioButton.Content> <TextBlock Text="муж, жена" /> </RadioButton.Content> </RadioButton> // ... и так далее .... <RadioButton IsChecked="{Binding RelationTypeMap[10]}"> <RadioButton.Content> <TextBlock Text="не родственник" /> </RadioButton.Content> </RadioButton>

Only earlier RelationTypeMap was bool [], and now it has become:

  ObservableCollection<bool> _relationTypeMap; public ObservableCollection<bool> RelationTypeMap { get => _relationTypeMap; set => Set("RelationTypeMap", ref _relationTypeMap, value); }

In the designer announced the event subscription:

  RelationTypeMap.CollectionChanged += RelationTypeMap_CollectionChanged;

In the event handler:

  private void RelationTypeMap_CollectionChanged(object sender, NotifyCollectionChangedEventArgs e) => OnReplacePropertiesNotification(e, "RelationOther");

In the inherited abstract class (the abstract class is optional; you can directly insert the code of this method into the handler, but it was more convenient for me):

  protected void OnReplacePropertiesNotification(NotifyCollectionChangedEventArgs e, params string[] properties) { if (e.Action == NotifyCollectionChangedAction.Replace) PropertiesNotification(properties); } protected void PropertiesNotification(params string[] properties) { foreach (string property in properties) RaisePropertyChanged(property); }

And the validation itself:

  #region Валидация public string this[string columnName] { get { string error = String.Empty; switch (columnName) { case "RelationOther": if (!string.IsNullOrEmpty(RelationOther) && RelationTypeMap.Any(x => x == true) && !RelationTypeMap[10]) error = "Ошибка! Указание описания не требуется"; break; // и так далее, другие поля... } return error; } } public string Error => string.Empty;

The goal was to validate the RelationOther field not only by changing the controls associated with this field, but also by changing the RadionButtons associated with RelationTypeMap, which are logically related to RelationOther. And this goal is fully achieved.

Although, of course, I had to repeat the event subscription and handler for the remaining 24 collections of bool-s, to which other RadioButton groups are tied.

Deleted the previous answer, so that the eyes are not callous.

Answer 2 · 2018-10-01T18:30:57

I do not know why you did not manage to remake an example for your version. There it was necessary to create a separate class for the radio button, plus recall the use of delegates in C #.

Create a class that will correspond to one radio button

 public class RadioButtonViewModel : INotifyPropertyChanged { private readonly string _template; private readonly Func<string, bool> _checkEqualsTemplate; private readonly Action<string> _assigningValue; //ctor public RadioButtonViewModel(string template, Func<string, bool> checkEqualsTemplate, Action<string> assigningValue) { if (String.IsNullOrEmpty(template)) throw new ArgumentNullException(nameof(template)); _template = template; _checkEqualsTemplate = checkEqualsTemplate ?? throw new ArgumentNullException(nameof(checkEqualsTemplate)); _assigningValue = assigningValue ?? throw new ArgumentNullException(nameof(assigningValue)); } public bool RadioButtonValue { get => _checkEqualsTemplate(_template); set => _assigningValue(_template); } public void RaisePropertyChanged() { PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(RadioButtonValue))); } public event PropertyChangedEventHandler PropertyChanged; }

The view model will be such a surrogate property remains in place.

 public class MainViewModel : INotifyPropertyChanged, IDataErrorInfo { //ctor public MainViewModel() { SetRadioButtons(); AnimalType = "NotAnimal"; } private void SetRadioButtons() { RadioButtons = new List<RadioButtonViewModel> { new RadioButtonViewModel("NotAnimal", OnCheckRadioButton, OnAssignToRadioButton), new RadioButtonViewModel("Cow", OnCheckRadioButton, OnAssignToRadioButton), new RadioButtonViewModel("Dog", OnCheckRadioButton, OnAssignToRadioButton), new RadioButtonViewModel("Cat", OnCheckRadioButton, OnAssignToRadioButton), }; } //метод проверяющий private bool OnCheckRadioButton(string arg) { return AnimalType.Equals(arg); } //метод присваивающий private void OnAssignToRadioButton(string obj) { AnimalType = obj; } //коллекция для привязки к радиокнопкам public List<RadioButtonViewModel> RadioButtons { get; set; } //суррогатное поле :) private string _AnimalType; public string AnimalType { get => _AnimalType; set { _AnimalType = value; //возбуждаем у каждой событие PropertyChanged foreach (var rb in RadioButtons) { rb.RaisePropertyChanged(); } //не забываем о значимом для нас свойстве OnPropertyChanged("Name"); } } private string _Name; public string Name { get => _Name; set { _Name = value; OnPropertyChanged(); } } //IDEI public string Error => String.Empty; public string this[string columnName] { get { //если выбрана первая радиокнопка - проверка не нужна! if (RadioButtons[0].RadioButtonValue) return String.Empty; if (String.IsNullOrEmpty(Name) || Name.Trim().Length <= 3) { return "Кличка не может быть короче 4-х символов"; } return String.Empty; } } //INPC public event PropertyChangedEventHandler PropertyChanged; private void OnPropertyChanged([CallerMemberName]string propertyName = null) { PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName)); } }

Very little had to change. Xaml such

 <Grid> <Grid.RowDefinitions> <RowDefinition Height="*" /> <RowDefinition Height="2*" /> </Grid.RowDefinitions> <StackPanel Grid.Row="0" Margin="20"> <RadioButton Content="Не животное" GroupName="Animal" IsChecked="{Binding RadioButtons[0].RadioButtonValue, Mode=TwoWay}"></RadioButton> <RadioButton Content="Корова" GroupName="Animal" IsChecked="{Binding RadioButtons[1].RadioButtonValue, Mode=TwoWay}"></RadioButton> <RadioButton Content="Собака" GroupName="Animal" IsChecked="{Binding RadioButtons[2].RadioButtonValue, Mode=TwoWay}"></RadioButton> <RadioButton Content="Кошка" GroupName="Animal" IsChecked="{Binding RadioButtons[3].RadioButtonValue, Mode=TwoWay}"></RadioButton> </StackPanel> <StackPanel Grid.Row="1"> <TextBlock Text="Кличка" Margin="100,0,0,0" /> <TextBox Width="200" Height="23" Text="{Binding Name, ValidatesOnDataErrors=True, UpdateSourceTrigger=PropertyChanged}"/> </StackPanel> </Grid>

The whole example can be downloaded here.

But I needed a much simpler solution that I found on my own.
But it was the experiments on your answer proposed earlier that helped me find this solution.

Validation of IDataErrorInfo for properties representing arrays bool []

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