1. MIS 324 -- Professor Sandvig MIS 324 Professor Sandvig
9/20/2018
Forms & Validation
MIS 324
Professor Sandvig

2. Overview What is validation Server & client validation
Validation tools in .NET MVC:
Model – DataAnnotations
View – HTML helpers
Controller - model

3. What is Validation Checking user inputs for: Datatype Length Required
Suspicious code:
HTML & Javascript

4. Why Validate Accidental user errors: Malicious hacking attempts
Missing fields
Invalid values
, phone, address, etc.
Malicious hacking attempts

5. Accidental user errors
Missing fields
Invalid credit card
Invalid mail address
Invalid dates
Invalid

6. Malicious Attacks Web forms expose your site to the world.
Typically writing user inputs to database.
Database contains valuable information
Customer information
Credit card info
Etc.

7. Malicious Attacks Hackers try to exploit security vulnerabilities
Sql Injection
Enter invalid data to throw exceptions
Expose code
Expose database info

8. Counter Measures Check format: Stronger measures: Email, phone, zip, …
Send with code
Send text message
Validate address against database
Checksum:
Credit cards
WWU student Id
ISBNs

9. Client and Server validation
Browser
HTML5 and JavaScript
Advantage:
Fast, no trip required to server
Disadvantage:
Easily circumvented
Save form to desktop, remove validation, submit

10. Server Validation Form data submitted to server
Data validated on server
Advantage:
Secure
Disadvantage:
Requires roundtrip to server
More complicated to implement

11. .NET MVC Validation Provides tools for easy validation: Client:
Javascript & HTML5
Server:
rechecks, rejects invalid data

12. .NET MVC Validation DataAnnotations
Decorate model with validation attributes
Required
Data type
length
Credit card
Etc.
Easy to implement both client and server validation

13. .Net MVC Validation Validation Attributes: Required StringLength Range
RegularExpression
CreditCard
CustomValidation
Address
FileExtension
MaxLength
MinLength
Phone

14. .NET MVC Validation Model: public class Student {
public int StudentId { get; set; }
[Required]
public string StudentName { get; set; }
[Range(5,50)]
public int Age { get; set; } }

15. .NET MVC Validation View: Client-side validation:
Include script libraries

16. .NET MVC Validation Model: Server-side validation:
Example: Calculator/MultiplyCalc

17. Summary Form Validation Important Time consuming
Accidental errors
Malicious attacks
Time consuming
.NET MVC provides convenient tools