[BUG] ValidationContex is not updated properly. about reactiveui.validation HOT 7 CLOSED

ReactiveUI.Validation with the fix is now shipped to NuGet as ^1.6.4.

from reactiveui.validation.

Thanks for reporting this! Curious if BindValidation is not showing validation errors in this case If yes, then probably the issue is in this class https://github.com/reactiveui/ReactiveUI.Validation/blob/main/src/ReactiveUI.Validation/Helpers/ReactiveValidationObject.cs

GitHub

reactiveui/ReactiveUI.Validation

Validation helpers for ReactiveUI based solutions, functioning in reactive way. - reactiveui/ReactiveUI.Validation

from reactiveui.validation.

Yes, just tried with the BindValidation and it works correctly. I updated the repo with the BindVlidation example.

from reactiveui.validation.

But I'm not sure that the problem is ReactiveValidationObject. Feels like it's some synchronization problem. In my observations, if we take IDataErrorInfo and make it rely on ValidationContext with some simple code like this

public string? this[string columnName]
{
    get
    {
        var temp = ValidationContext.Validations
            .OfType<IPropertyValidationComponent<ClassicValidationViewModel>>()
            .Where(validation => !validation.IsValid && validation.ContainsPropertyName(columnName))
            .Select(validation => validation.Text?.ToSingleLine()).FirstOrDefault();
        return temp;
    }
}

We get the same problem as with ReactiveValidationObject that uses INotifyDataErrorInfo
During the debug, when we change CustomerCode in viewmodel lets say to empty and the IDataErrorInfo is firing, we see that the ValidationContext.Validations.IsValid is true

from reactiveui.validation.

I encountered this too, and I think it indeed has to do with INotifyDataErrorInfo implementation in ReactiveValidationObject. AFAIK the WPF framework expects the validation change events to explicitly contain the changing property name as a parameter of DataErrorsChangedEventArgs, but now that event is triggered with a string.Empty only when ValidationContext.ValidationStatusChange occurs.

It should trigger the ErrorsChanged -event with affected main property whenever any validator error changes, not just the state. That way two validators (e.g. not empty, and must meet some format requirement) can be indicated and triggered correctly.

A workaround could be to add a protected RaiseErrorChanged(Expression<...> viewModelProperty) to the ReactiveValidationObject so you could listen to the error message changes from a specific ValidationRule and trigger a new ErrorChanged event with the property name.

from reactiveui.validation.

Looking into this now. Most likely we are hitting https://stackoverflow.com/a/24837028/11351183

Stack Overflow

UI not calling INotifyDataErrorInfo.GetErrors()

I have a model implementing both INotifyPropertyChanged and INotifyDataErrorInfo. The Property changed event fires when ever I have a property modified, but for some reason when I raise the Error e...

from reactiveui.validation.

This issue has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.

from reactiveui.validation.