ValidatingViewModel

Class in Oadm.Sdk.Client.Validation · Oadm.Sdk.Client.dll

Base class of every form view model (host and plugins): an ObservableObject that reports field errors through INotifyDataErrorInfo from the rules registered on ValidatingViewModel.Validation. Setting a field property (one with a rule) marks it edited and shows its error; any property change re-runs the rules (rules may depend on other properties, e.g. a mode choice). Bind the submit button to ValidatingViewModel.IsFormValid (IsEnabled) and ValidatingViewModel.FormError (ToolTip.Tip, with ToolTip.ShowOnDisabled), or use the command’s CanExecute with FormValidator.IsValid and override ValidatingViewModel.OnValidationChanged to refresh it.

public abstract class ValidatingViewModel : ObservableObject, INotifyDataErrorInfo, IFormFieldVisits

Inherits ObservableObject
Implements INotifyDataErrorInfo, IFormFieldVisits

Guide: UI kit

Example

public MyViewModel()
{
    Validation.Rule(nameof(UserName), () => UserName.Trim().Length == 0 ? "Enter a user name." : null);
    Validation.Validate();
}

Constructors

ValidatingViewModel

ValidatingViewModel()

Protected: for classes that derive from it

Creates ValidatingViewModel.Validation; register the rules in the constructor of the derived class.

Properties

FormError

string? FormError { get; }

Why the form cannot be submitted (the first field error), for the submit button’s tooltip.

HasErrors

bool HasErrors { get; }

Any error is visible below its field.

IsFormValid

bool IsFormValid { get; }

No field error, shown or not: submit buttons are enabled.

Validation

FormValidator Validation { get; }

Protected: for classes that derive from it

The rules and the edited / submitted state of this form.

Methods

ErrorOf

string? ErrorOf(string propertyName)

The visible error of a property (tests, code-behind free views).

FieldLeft

void FieldLeft(string propertyName)

The user left the input of propertyName (FormField on lost focus): its error shows now, also when the field was never edited (an empty required field).

GetErrors

IEnumerable GetErrors(string? propertyName)

The shown errors of a property (INotifyDataErrorInfo).

OnValidationChanged

virtual void OnValidationChanged()

Protected: for classes that derive from it

Called after any error changed (refresh command CanExecute here).

Events

ErrorsChanged

event EventHandler<DataErrorsChangedEventArgs>? ErrorsChanged

The shown errors of a property changed (INotifyDataErrorInfo).