Externally validate autocomplete

[mdmontesinos]

We've already discussed supporting fluent validations on the autocomplete component in #5129.

Meanwhile, I was wondering if it's possible to trigger the internal validation of the component from an external event.

In this way, I could still combine (kind of) my fluent validations for all the simple text fields with the custom validation for the autocomplete components. Therefore, when trying to submit the form, all the fields (regular or autocomplete) should trigger validation and display their corresponding messages.

EDIT: The autocomplete validation is usually triggered by the submit button and the validation displays. However, I require clearing the value of the second autocomplete when the first one changes and, in this case, submitting the form does not trigger the validation of the second autocomplete and results in allowing a null/empty string value passing through.

For example:

<Form @onsubmit="@Submit" autocomplete="off">
    <Validations @ref="fluentValidations" Model="@model" Mode="ValidationMode.Auto" ValidateOnLoad="false" HandlerType="typeof(FluentValidationHandler)">
        <Div>
            <Validation>
                <Field>
                    <FieldLabel For="@nameof(model.Name)" RequiredIndicator>Nombre</FieldLabel>
                    <FieldBody>
                        <TextEdit ElementId="@nameof(model.Name)" Placeholder="Nombre" @bind-Text="@model.Name">
                            <Feedback>
                                <ValidationError />
                            </Feedback>
                        </TextEdit>
                    </FieldBody>
                </Field>
            </Validation>
        </Div>
        <small>Dirección</small>
        <Div>
            <Div>
                <Field>
                    <FieldLabel RequiredIndicator>País</FieldLabel>
                    <FieldBody>
                        <Autocomplete @ref="countryAutocomplete" TItem="string"
                                      TValue="string"
                                      Data="@AddressDataService.GetCountries()"
                                      TextField="@(( item ) => item)"
                                      ValueField="@(( item ) => item)"
                                      Placeholder="País"
                                      MinLength="0"
                                      FreeTyping="false"
                                      Validator="@(e => AutocompleteValidator(e, "Debe seleccionar el país"))"
                                      @bind-Search="@selectedCountry"
                                      @bind-SelectedText="@selectedCountry"
                                      SelectedValueChanged="OnSelectedCountryChanged"
                                      Immediate="true">
                            <NotFoundContent>No se han encontrado países</NotFoundContent>
                        </Autocomplete>
                    </FieldBody>
                </Field>
                <Field>
                    <FieldLabel RequiredIndicator>Provincia</FieldLabel>
                    <FieldBody>
                        <Autocomplete @ref="stateAutocomplete" TItem="string"
                                      TValue="string"
                                      Data="@AddressDataService.GetStates()"
                                      TextField="@(( item ) => item)"
                                      ValueField="@(( item ) => item)"
                                      Placeholder="Provincia"
                                      MinLength="0"
                                      FreeTyping="false"
                                      Validator="@(e => AutocompleteValidator(e, "Debe seleccionar la provincia"))"
                                      @bind-Search="@selectedState"
                                      @bind-SelectedText="@selectedState"
                                      SelectedValueChanged="OnSelectedStateChanged"
                                      Disabled="@(string.IsNullOrWhiteSpace(Clinic.Address.Country))"
                                      Immediate="true">
                            <NotFoundContent>No se han encontrado provincias</NotFoundContent>
                        </Autocomplete>
                    </FieldBody>
                </Field>
            </Div>
        </Div>
    </Validations>


    <Div>
        <Button Type="ButtonType.Submit">
            Guardar
        </Button>
    </Div>
</Form>

@code {
    Autocomplete<string, string>? countryAutocomplete;
    Autocomplete<string, string>? stateAutocomplete;

    Validations? fluentValidations;

    private bool AutocompleteValidator(ValidatorEventArgs e, string message)
    {
        if (e.Value == null || e.Value.ToString() == string.Empty)
        {
            e.Status = ValidationStatus.Error;
            e.ErrorText = message;
        }

        return e.Status == ValidationStatus.Error;
    }

    private async Task Submit()
    {
        if (!(await fluentValidations!.ValidateAll()))
        {
            return;
        }

        if (!countryAutocomplete.Validate() || !stateAutocomplete.Validate())
        {
            return;
        }
        //...
    }