Async Validations

[danbaechtold]

Validation with async Validator functions don't work (when e.Status is set asynchroniously):

<Validations @ref="validations" ValidateOnLoad="false" StatusChanged="OnValidationsChanged">
    <Field>
        <FieldLabel>Label</FieldLabel>
        <Validation Validator="@ValidateFunc">
            <TextEdit @bind-Text="@Text">
                <Feedback>
                    <ValidationError>Error</ValidationError>
                </Feedback>
            </TextEdit>
        </Validation>
    </Field>
</Validations>

private async void ValidateFunc(ValidatorEventArgs e)
{
    // e.Status = ValidationStatus.Success; // THIS WORKS

    bool valid = await RemoteValidateFunc(e.Value);
    e.Status = ValidationStatus.Success; // THIS DOESN'T WORK (StatusChanged not fired)

    // validations.ValidateAll(); // WORKAROUND (but invalidates all blank fields)
}

It would be very helpful if this could be supported - or is there another way this should be done?

[stsrki]

For this scenario I should probably refactor Validator and convert it to EventCallback instead of plain event. It makes sense as it should be more flexible, especially for this kind of situations.

But since it's probably a larger change, and breaking change I will schedule it for one of next milestones.

[CPlusPlus17]

Is there a workaround? I'm facing multiple problems to get this working:

• I'm using fluent validations
• One validation uses a REST endpoint

The HttpClient only work as async, waiting with .Result isn't supported with Blazor.

validations.ValidateAll()

Throws an

Object reference not set to an instance of an object.

at this stage in the code path. So I'm out of solutions for the moment?

[stsrki]

The first prototype of async validation #1958