如何有条件地验证 ASP.NET 核心 Web ZDB974238714CA8DE634A7CE1D08 中的整个 model？

Question

I am using net core 3.1 in my Web-Application. I am stuck in a situation where I want to validate a model conditionally. Below is my models:

Studen tModel:

public class StudentModel 
{
  public int StudenId {get; set;}
  public string StudenName {get; set;}
  public bool HasSiblings {get; set;}
  public List<SiblingModel> SiblingDetails {get; set;}
}

Sibling Model

public class SiblinModel
{
  public int SiblingId {get; set;}
  [Required]
  public string SiblingName {get; set;}
}

Now, I want to validate SiblingModel only if HasSibling in StudentModel is set to true.

Note : I do not want to use IValidatableObject and then validate each and every property of SiblingModel. I have used the above models only for example. In the actual model, I have validation for around 10-12 fields. So writing validation checks for each and every attribute would be a tedious task.

Is there a way through which I can validate the entire model conditionally ie if HasSibling is set to true then only validate Sibling Model.

Also, I am using action filter in my project to check for validations in each and every request automatically.

public class ValidationFilterAttribute : ActionFilterAttribute
{

    public override void OnActionExecuting(ActionExecutingContext context)
    {

        if (!context.ModelState.IsValid)
        {

            ApiResponseModel<IEnumerable<ValidationErrorModel>> apiResponseModel = new ApiResponseModel<IEnumerable<ValidationErrorModel>>();

            apiResponseModel.ResponseCode = (int)HttpStatusCode.BadRequest;
            apiResponseModel.ResponseMessage = string.Join(" ",
                context.ModelState.Values.Where(E => E.Errors.Count > 0)
                .SelectMany(E => E.Errors)
                .Select(E => E.ErrorMessage)
                .ToArray());
            apiResponseModel.ResponseData = null;

            context.Result = new OkObjectResult(apiResponseModel);
        }
    }
}

So is there any way around or I have to manually write Validations check using IValidatableObject.

Answer 1

Well, your question is ambiguous:

Is there a way through which I can validate the entire model conditionally ie if HasSibling is set to true then only validate Sibling Model.

If you want to validate the entire model based on a property, using ActionFilter is a good choice. If you want conditionally validate a property based on another property below solution works.

Here is an example of RequiredIf attribute:

public sealed class RequiredIfAttribute : ValidationAttribute
{
    private readonly RequiredAttribute _innerRequiredAttribute = new RequiredAttribute();
    private readonly string _dependentPropertyName;
    private readonly object[] _targetValues;

    public RequiredIfAttribute(string dependentPropertyName, params object[] targetValues)
    {
        _dependentPropertyName = dependentPropertyName;
        _targetValues = targetValues;
    }

    protected override ValidationResult IsValid(object value, ValidationContext validationContext)
    {
        var containerType = validationContext.ObjectInstance.GetType();
        var field = containerType.GetProperty(_dependentPropertyName);

        if (field == null)
            return ValidationResult.Success;

        // get the value of the dependent property
        var dependentValue = field.GetValue(validationContext.ObjectInstance, null);

        foreach (var obj in _targetValues)
        {
            // compare the value against the target value
            if (dependentValue.GetHashCode().Equals(obj.GetHashCode()))
            {
                // match => means we should try validating this field
                if (!_innerRequiredAttribute.IsValid(value))
                    // validation failed - return an error
                    return new ValidationResult(ErrorMessage, new[] { validationContext.MemberName });
            }
        }
        return ValidationResult.Success;
    }
}

And in your model:

public class StudentModel 
{
  public int StudenId {get; set;}

  public string StudenName {get; set;}

  public bool HasSiblings {get; set;}

  [RequiredIf(nameof(HasSiblings), true)]
  public List<SiblingModel> SiblingDetails {get; set;}
}