Tenekon.Extensions.FluentValidation.Blazor

Scoped, nestable FluentValidation for Blazor forms. Use it to validate the form root, a nested model, or a routed region of a form without giving up Blazor's EditContext flow.

Note

Status: 1.0-alpha. The public API is intended to be stable, but changes may occur as the library matures.

Note

Repository rename: this repository used to be called Tenekon.FluentValidation.Extensions. It was renamed to Tenekon.Extensions.FluentValidation.Blazor to match the single package it ships.

Why This Package

Blazor's built-in validation flow is centered around a single EditContext, but real forms often split into nested components, repeating items, and scoped sub-regions.

This package lets you:

• validate the whole form with FluentValidation
• attach validators to nested models and collection items
• keep nested validators connected to the parent form lifecycle
• limit validation to selected branches of the model when needed

Installation

Install the package:

dotnet add package Tenekon.Extensions.FluentValidation.Blazor

If you want to resolve validators from dependency injection by using ValidatorType, also install:

dotnet add package FluentValidation.DependencyInjectionExtensions

If you prefer, you can skip the DI extensions package and pass a validator instance through the Validator parameter instead.

Quickstart

1. Register your validators

using FluentValidation;

builder.Services.AddValidatorsFromAssemblyContaining<PersonValidator>();

2. Create a model and validator

using FluentValidation;

public sealed class Person
{
    public string? Name { get; set; }
}

public sealed class PersonValidator : AbstractValidator<Person>
{
    public PersonValidator()
    {
        RuleFor(x => x.Name).NotEmpty();
    }
}

3. Use EditModelValidatorRootpath inside your form

Add the package namespace to _Imports.razor or directly in the component:

@using Microsoft.AspNetCore.Components.Forms
@using Tenekon.Extensions.FluentValidation.Blazor

Then wire the validator into your EditForm:

<EditForm Model="_model" OnValidSubmit="HandleValidSubmit">
    <EditModelValidatorRootpath ValidatorType="typeof(PersonValidator)" />

    <label for="name">Name</label>
    <InputText id="name" @bind-Value="_model.Name" />
    <ValidationMessage For="() => _model.Name" />

    <button type="submit">Save</button>
</EditForm>

@code {
    private readonly Person _model = new();

    private Task HandleValidSubmit()
    {
        return Task.CompletedTask;
    }
}

If you want to bypass DI, use Validator="new PersonValidator()" instead of ValidatorType="typeof(PersonValidator)".

Which Component Should I Use?

Component	Use it when
EditModelValidatorRootpath	You want to validate the main model of the current form or cascaded EditContext.
EditModelValidatorSubpath	You want to validate a nested object or a repeated item inside the main model.
EditModelValidatorRoutes	You want a validator to act only on selected branches of the model. Use it inside EditModelValidatorRootpath or EditModelValidatorSubpath.
EditModelScope	You want to create a scoped validation region with its own EditContext behavior.

For worked examples of all four components, see the Validator Components Cookbook.

Compatibility And Dependencies

• Target frameworks: net8.0, net9.0, net10.0
• FluentValidation: 12.x
• Blazor forms integration: the package selects the matching Microsoft.AspNetCore.Components.Forms version for each target framework
• Internal dependency: FastExpressionCompiler 5.x

Documentation

• Cookbook: start here for usage patterns and copyable scenarios.
• Architecture: read this when you want the mental model behind root, subpath, routes, and scope behavior.
• Motivation: read this when you want the design rationale and why the package is split into rootpath, subpath, routes, and scope.

Development

git clone https://github.com/tenekon/Tenekon.Extensions.FluentValidation.Blazor.git
cd Tenekon.Extensions.FluentValidation.Blazor
dotnet test

Questions, feedback, and design discussion are welcome in the Tenekon Community Discord.

License

MIT License. See LICENSE for details.