Control's Custom Validations (CalendarDatePicker)

[Lonnewolf46]

Hello there, I hope everyone is having a nice day, afternoon or night. I stumbled across some issues that I have not yet been able to solve and can't still figure out; so maybe someone here can point me in the right direction.
Using the CommunityToolkit.Mvvm

Basically, they revolve around two issues:
Issue 1: Validations on CalendarDatePicker
I thought of doing a Custom Validation in case the user tried to input a date higher than todays, so I got to it and ended up with this in the ViewModel:

Does not work
[ObservableProperty]
[NotifyDataErrorInfo]
[CustomValidation(typeof(PacientsAddViewModel), nameof(ValidateBirth)")]
private DateTime? _nacimientoParam;

And updating it to this code from bellow, it works, which leads me to Issue 2, which is that, even when it does validate, it does it once and the UI never updates again, but the validation function still prints the console logs, which tells me that it is going through there.

Works once
[Required]
[ObservableProperty]
[NotifyDataErrorInfo]
[CustomValidation(typeof(PacientsAddViewModel), nameof(ValidateBirth)")]
private DateTime? _birthParam;

The [Required] works wonderfully though, which leads me to believe I am missing something when it comes to Custom Validators, and also, doing this exact same thing on TextBox works with no issues (even without the Required tag), but for CalendarDatePicker and NumericUpDown I couldn't make it work.

I tried to find information and ended up here as a last resort, believe me, I don't like to come bother in Github forums, maybe this is not the right one; if so, please tell me and I'll go there.

First validation

Second validation, after doing it right once.

Thank you!!!

[timunie]

Can you show your custom validation impl?

[Lonnewolf46]

Thank you for replying, and I'd like to apologize beforehand for any obvious novice issues this may have; it's my first time with MVVM and Avalonia, but all in all, it's been quite a gentle learning experience compared to others I had.

This is similar to the one I tested with TextBox and worked.
This is the function:

public static ValidationResult ValidateBirth(DateTime? date, ValidationContext context)
    {
        PacientsAddViewModel instance = (PacientsAddViewModel) context.ObjectInstance;
        if(date == null)
        {
            Console.WriteLine("Null, nothing to check");
            return ValidationResult.Success;
        }

        if (instance.EsFuturo(date.Value))//EsFuturo is basically a boolean on date > DateTime.Now;
        {
            Console.WriteLine("Returning error");
            return new ValidationResult("Invalid birthdate", new[] {nameof(BirthParam)});
        }
        Console.WriteLine("All good");
        return ValidationResult.Success;
    }

Once again, thanks.

[timunie]

works perfectly on my end. Maybe debug into EsFuturo ?

Only change I did additinally is

-   public static ValidationResult ValidateBirth(DateTime? date, ValidationContext context)
+   public static ValidationResult? ValidateBirth(DateTime? date, ValidationContext context)
    {
        MainWindowViewModel instance = (MainWindowViewModel) context.ObjectInstance;
        if(date == null)
        {
            Console.WriteLine("Null, nothing to check");
            return ValidationResult.Success;
        }

        if (date.Value > DateTime.Today)//EsFuturo is basically a boolean on date > DateTime.Now;
        {
            Console.WriteLine("Returning error");
            return new ValidationResult("Invalid birthdate", new[] {nameof(BirthParam)});
        }
        Console.WriteLine("All good");
        return ValidationResult.Success;
    }

[Lonnewolf46]

Even then, nothing; but now I have an idea as to why it is giving me these issues. It is likely due to another library that may have interfered with the UI. The validation is happening and "Has Errors" throws the corresponding errors and, after checking the content; it seems that it all goes as planned.

Anyways, I'll mark your answer as the good one, because it led me to finding the issue.
Thank you for your help.

[timunie]

Extract it into a minimum sample and see if it reproduces. Then add the dep. That you think could be interfering and check again.