Advanced validation in Blazor using FluentValidation
You are probably familiar with the great FluentValidation validation library - defacto industry standard for any advanced validation scenarios in .NET.
There has been a few attempt to integrate FluentValidation with Blazor Forms:Blazored.FluentValidation, Accelist.FluentValidation.Blazor, just to name few, however none supports all of the advances scenarios like asynchronous validation, validation severity, rulesets.
I wonder why would anybody use FluentValidation in Blazor when it's advanced features are unsupported.
To solve this, I have released vNext.BlazorComponents.FluentValidation nuget package.
It's based on Chris Sainty's BlazorValidator with backward compatible API, but I have added support for:
- Asynchronous validation
async Task OnSubmited(EditContext editContext)
{
editContext.Validate();
var validationResult = await editContext.GetValidationResultAsync(); //make sure async valiation completes
if (validationResult.IsValid)
{
await JS.InvokeVoidAsync("alert", "Form Submitted Successfully!");
}
}2. Validation Severity
<FluentValidationValidator Severity="Severity.Error" />or alternatively:
bool overrideWarnings = false;
async Task OnSubmited(EditContext editContext)
{
editContext.Validate();
var validationResult = await editContext.GetValidationResultAsync();
bool isValid = validationResult.IsValid;
if (overrideWarnings)
{
isValid = validationResult.Any(e => e.Severity == Severity.Error);
}
if (isValid)
{
await JS.InvokeVoidAsync("alert", "Form Submitted Successfully!");
}
}
3. Custom validator factory:
<FluentValidationValidator ValidatorFactory="CreateValidator" />
IValidator CreateValidator(ValidatorFactoryContext ctx)
{
if (ctx.Model == Person.Address)
{
//set custom flags on the validotor
return new AddressValidator() { CheckPostalCode = false };
}
return (IValidator)ctx.ServiceProvider.GetService(ctx.ValidatorType);
}
4. Designed for extensibility
You can extent the FluentValidator component by inheriting from it and override virtual methods
virtual IValidator? GetValidator(FieldIdentifier fieldIdentifier = default);
virtual string MapValidationFailureToMessage(ValidationFailure failure, ValidationResult result, ValidationContext<object> validationContext);
virtual ValidationContext<object> CreateValidationContext(IValidator validator, FieldIdentifier fieldIdentifier = default);
virtual void ConfigureValidationStrategy(ValidationStrategy<object> options, IValidator validator, FieldIdentifier fieldIdentifier = default)Let me know if you need some other feature, I will surely consider adding it.
Check out also:
