: Use .Must() to define custom logic for specific properties.
using FluentValidation; var builder = WebApplication.CreateBuilder(args); // Register all validators from the assembly containing ProductValidator builder.Services.AddValidatorsFromAssemblyContaining (); var app = builder.Build(); Use code with caution. Handling Validation Errors Gracefully fluentvalidation
: It offers superior control over how validation errors are formatted and returned to the client. Getting Started: Installation and Setup Getting Started: Installation and Setup When a validation
When a validation fails, you want to return a standardized error response. Many developers use to ensure the API fails gracefully. You can create a global exception handler or a validation filter to catch ValidationException and return a 400 Bad Request with structured error details. Advanced Features FluentValidation goes beyond simple null checks: var builder = WebApplication.CreateBuilder(args)
In your Program.cs , you can register all validators in your assembly so they are automatically available via Dependency Injection:
: Compare values across different fields, such as ensuring an EndDate is after a StartDate . Summary Table: Comparison at a Glance Data Annotations FluentValidation Location Directly on Model properties Separate Validator class Complexity Best for simple checks Excellent for complex logic Unit Testing Difficult/Clunky Clean Code Models become cluttered Models remain "POCO"