Input Validation for ASP.NET Core CASENET Practice Questions (Page 7)

Questions 31–35

1. 31application · medium

   A development team is building an ASP.NET Core MVC registration form for a financial application. The form collects a username, email, and account balance. The team must ensure that the username is required and between 3 and 20 characters, the email is a valid email format, and the account balance is non-negative. They also need to prevent overposting attacks. Which approach should they use?

   • AApply [Required], [StringLength(3, 20)], [EmailAddress], and [Range(0, double.MaxValue)] data annotations to the model properties and use a view model for binding.
   • BApply data annotations to the entity model and bind the entity directly in the action method.
   • CUse [Remote] attributes on each property to validate them asynchronously on the client side.
   • DManually validate each property in the controller action using if statements and return a generic error message.
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2. 32foundation · easy

   In an ASP.NET Core API controller decorated with [ApiController], what happens automatically when model validation fails?

   • AA 500 Internal Server Error is returned.
   • BA 400 Bad Request response with a ProblemDetails body is returned.
   • CThe action method is still executed with null values.
   • DThe model is automatically corrected and retried.
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4. 33application · medium

   In an ASP.NET Core MVC application, a booking form has `StartDate` and `EndDate` properties. The business rule requires that `EndDate` must be later than `StartDate`. The team wants to enforce this rule during model binding so that ModelState.IsValid becomes false when the rule is violated. Which approach should they take?

   • AImplement IValidatableObject on the model class and add the comparison logic in the Validate method.
   • BPerform the comparison in the controller action after checking ModelState.IsValid.
   • CAdd a [Compare] attribute to the EndDate property with the StartDate property name.
   • DCreate a custom validation attribute and apply it to the StartDate property only.
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5. 34expert · hard

   An ASP.NET Core MVC application has a model with `StartDate`, `EndDate`, and `MaxDurationDays`. The team needs to enforce two rules: EndDate must be after StartDate, and the duration must not exceed MaxDurationDays. They also need to ensure that validation errors are associated with the EndDate field so they display next to it. Which approach should they use?

   • AUse [Compare] and [Range] attributes on the properties.
   • BImplement IValidatableObject and return validation results with memberNames set to "EndDate".
   • CPerform the validation in the controller action and add errors to ModelState with the key "EndDate".
   • DCreate two custom validation attributes and apply them to the EndDate property.
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6. 35expert · hard

   An ASP.NET Core Web API controller is decorated with [ApiController]. The team wants to customize the validation error response to include a custom error code and a correlation ID, while still using the ProblemDetails format. What is the most appropriate way to achieve this?

   • AOverride the default behavior by configuring a custom InvalidModelStateResponseFactory in the AddControllers options.
   • BAdd a custom middleware that intercepts all 400 responses and modifies the body.
   • CDisable the automatic response and manually check ModelState.IsValid in every action.
   • DUse an exception filter to modify the response after it is generated.
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