Input Validation for MVC CASENET Practice Questions (Page 7)

Questions 31–35

1. 31application · medium

   An MVC application has a controller action that accepts JSON data from an AJAX request. When validation fails, the developer wants to return the validation errors to the client in a format that can be easily processed by JavaScript. Which approach is most appropriate?

   • AReturn an Ok response with the validation errors in the response body.
   • BThrow an exception and let the global exception handler return a generic error message.
   • CReturn a BadRequest response with the ModelState errors serialized as JSON.
   • DReturn a RedirectToAction response that displays the validation errors in a new view.
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2. 32application · medium

   A social media application has a registration form where users choose a username. The username must be unique across the entire user base. The team wants to provide immediate feedback to the user as they type, without submitting the entire form, but also wants to ensure the check is performed securely on the server. Which approach should be used?

   • AUse a [StringLength] attribute on the Username property to limit the length of the username.
   • BUse a JavaScript function that checks the username against a static list of taken usernames embedded in the page.
   • CUse the [Remote] attribute on the Username property and create a controller action that checks the database for uniqueness and returns a JSON result.
   • DUse a [RegularExpression] attribute on the Username property to ensure it matches a valid username pattern.
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4. 33application · medium

   An MVC application has a Booking model with CheckInDate and CheckOutDate properties. The business rule is that CheckOutDate must be later than CheckInDate. The developer also needs to ensure that CheckInDate is not in the past. Which approach correctly implements both rules with appropriate validation error messages?

   • AAdd [FutureDate] (a custom attribute) to CheckInDate and [GreaterThan("CheckInDate")] (a custom attribute) to CheckOutDate.
   • BAdd [DataType(DataType.Date)] to both properties and implement IValidatableObject on the Booking class to compare the two dates and check against DateTime.Now.
   • CPerform both checks in the controller action and add ModelState errors manually.
   • DAdd [Range(typeof(DateTime), "1/1/2020", "12/31/2099")] to CheckInDate and [Compare("CheckInDate")] to CheckOutDate.
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5. 34foundation · easy

   Which of the following is a common way to extract validation errors from ModelState for a JSON response?

   • AUse ModelState.ToJson()
   • BUse ModelState.Errors property
   • CSerialize the entire ModelState object directly
   • DIterate over ModelState and collect error messages into a dictionary
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6. 35application · medium

   A project management application has a form for creating a new task. The task model has a Title property that is required and must be between 5 and 100 characters. The team wants to enforce this rule using data annotations. Which combination of attributes should be applied to the Title property?

   • A[StringLength(100)] only
   • B[Required] and [RegularExpression(@"^.{5,100}$")]
   • C[Required] and [StringLength(100, MinimumLength = 5)]
   • D[Required] and [Range(5, 100)]
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