Does Volo.Abp.Validation support validating only a single property in a DTO?

[LenFon]

During form validation, in some cases, when entering a value in a specific form field, I need to immediately validate whether the input is valid. However, I have not found any method in Volo.Abp.Validation that can fulfill this requirement.

[maliming]

hi

Can you share more info about your use case?

[maliming]

hi

We will validate the object in the interceptor, and it isn't easy to use user-defined parameter.
You can directly use the FluentValidation's Validator class for validation instead of using ABP's ObjectValidator.

[LenFon]

In my scenario, the frontend project (such as WPF or MAUI) uses Volo.Abp.Validation directly, without relying on interceptors. If I were to use FluentValidation directly, switching to another validation library in the future would become cumbersome and tightly coupled. In contrast, Volo.Abp.Validation provides an abstraction layer that meets our validation requirements while reducing the need to learn and depend on external libraries. It offers better maintainability and flexibility, especially in frontend applications where form-level validation is manually controlled.

[LenFon]

Would it be possible to add a public string[]? OnlyValidateProperties { get; } property to ObjectValidationContext?
With this addition, I can implement the rest of the logic by customizing IObjectValidator and IObjectValidationContributor accordingly.

[LenFon]

public class ObjectValidationContext
{
    .......

    public string[]? OnlyValidateProperties { get; }

    public ObjectValidationContext([NotNull] object validatingObject, string[]? onlyValidateProperties = default)
    {
          ......
          OnlyValidateProperties = onlyValidateProperties;
    }
}

//ObjectValidator.cs
public virtual async Task<List<ValidationResult>> GetErrorsAsync(object validatingObject, string? name = null, bool allowNull = false, string[]? onlyValidateProperties = default)
{
........
     var context = new ObjectValidationContext(validatingObject, onlyValidateProperties);
.........
}


//FluentObjectValidationContributor.cs
public virtual async Task AddErrorsAsync(ObjectValidationContext context)
{
     var type = typeof(ValidatorHelper<>).MakeGenericType(context.ValidatingObject.GetType());
     var validatorHelper = (IValidatorHelper)Activator.CreateInstance(type, _serviceProvider)!;

     await validatorHelper.AddErrorsAsync(context);
}

private interface IValidatorHelper
{
    Task AddErrorsAsync(ObjectValidationContext context);
}

private class ValidatorHelper<T>(IServiceProvider  serviceProvider) : IValidatorHelper
{
    private readonly IValidator<T>? _validator = serviceProvider.GetService<IValidator<T>>();

    public async Task AddErrorsAsync(ObjectValidationContext context)
    {
        if (_validator == null)
        {
            return;
        }

        var result = context.OnlyValidateProperties is null || context.OnlyValidateProperties.Length == 0
               ? await _validator.ValidateAsync((T)context.ValidatingObject)
               : await _validator.ValidateAsync((T)context.ValidatingObject, options =>
               {
                     options.IncludeProperties(context.OnlyValidateProperties);
               });

        if (!result.IsValid)
        {
             context.Errors.AddRange(
                result.Errors.Select(error =>new ValidationResult(error.ErrorMessage, [error.PropertyName]))
              );
        }
    }
}

[LenFon]

//DataAnnotationObjectValidationContributor.cs

protected virtual void ValidateObjectRecursively(List<ValidationResult> errors, object? validatingObject, int currentDepth, string[]? OnlyValidateProperties = default)
{
........
    if (currentDepth == 1 && onlyValidateProperties is not null && onlyValidateProperties.Length > 0)
    {
        AddErrors(errors, validatingObject, onlyValidateProperties);
    }
    else
    {
        AddErrors(errors, validatingObject);
    }
.......
}


public void AddErrors(List<ValidationResult> errors, object validatingObject, string[]? onlyValidateProperties = default)
{
   var properties = TypeDescriptor.GetProperties(validatingObject).Cast<PropertyDescriptor>()
         .WhereIf(onlyValidateProperties is not null && onlyValidateProperties.Length > 0,w => onlyValidateProperties!.Contains(w.Name));

.......
}