FluentValidation in .net

Steps

• Create a DTO.
• Create a custom validator of AbstractValidator type.
• Create rules.
• Informed location of custom validators to dot net.
• Injected validator in controller.
• Executed ValidatorAsync.
• Received result.
• Check result Is not Valid.
• Return error response.

Validation Result

• Validation successful – IsValid true.
• Validation failed – IsValid false.
• List of validation failure received.

ValidationFailure

• Property Name
• Error Message
• Property Value
• Custom State
• Severity
• Error Code

Model Binding & Custom Validator

• FluentValidation Custom validator will only run once asp.net model binding is successful.
• When asp.net model binding is failed, error is stored in ModelState.
• FluentValidation custom validator is automatically validate the model after model binding by framework when [ApiController] attribute is applied and FluentValidation is registered.