ASP.NET MVC shipped both client- and server-side validation support.

1. Validations in MVC Eyal Vardi CEO E4D Solutions LTDMicrosoft MVP Visual C#blog: www.eVardi.com

2. Agenda Data Annotations Validation Self Validation Models Custom Validation Entity Level Validation Client-Side Validation Remote Validation

3. Validation Scenario (WWWH) When to validate? During data input On submitting data After submission What to validate? Property Entity Domain Operation Where to validate? Server Only Client + Server How do we write logic? Attributes Add code in operation Custom validation class

4. Model Data Annotations Specify validation for individual fields in the data model. System.ComponentModel.DataAnnotations Provide both client and server validation checks with no additional coding required by you. public class ProductMD{ [StringLength(50), Required] public object Name { get; set; } [Range(0, 9999)] public object Weight { get; set; }}

5. Metadata Classes The MetadataTypeAttributeattribute enables you to associate a class with a data-model partial class. [MetadataTypeAttribute( typeof( Employee.EmployeeMetadata ) )] publicpartialclassEmployee } internalsealedclassEmployeeMetadata } [StringLength(60)] [RoundtripOriginal] public string AddressLine { get; set; } } }

6. Server Validation public ActionResult Edit( Contact contact ){ if (ModelState.IsValid) { // The model Valid. } else { ModelState.AddModelError( "*", "contract not valid" ); } return View(contact); } Validate Model

7. Server Validation [AcceptVerbs(HttpVerbs.Post)]public ActionResult Edit( int id, FormCollection collection ){ Product prd = GetProduct(id); if ( ! TryUpdateModel( prd ) ) { return View(prd); } // Persist changes back to database _db.SaveChanges(); // Perform HTTP redirect to details page for the saved Dinner return RedirectToAction("Details", new { id = prd.ProductID });} Validate Product

8. Validation Attributes Metadata Validation Attributes: [Required] [Exclude] [DataType] [Range] [StringLength(60)] [RegularExpression] [AllowHtml] [Compare] [MetadataTypeAttribute( typeof( Employee.EmployeeMetadata ) )] publicpartialclassEmployee } internalsealedclassEmployeeMetadata } [StringLength(60)] [RoundtripOriginal] public string AddressLine { get; set; } } }

9. Self Validation Models Validation Order: Property attributes Class attributes Validate interface If you have any DataAnnotations attributes on your properties that fail then your Validate implementation will not be called.

10. Self Validation Models public class UserModel : IValidatableObject{ public int Age { get; set; } public IEnumerable<ValidationResult> Validate( ValidationContext vc ) { if( Age < 18 ) { yield return new ValidationResult( "User age should be higher then 18", new string[] { "Age" }); } }}

11. CustomValidation Attribute The custom class must: Public, static method At lest 1 parameter Returns ValidationResult public class MyValidator { public static ValidationResultValidationAddress(short value,ValidationContextcontext) { ValidationResultresult = ( value >= 0.0 && value <= 100.0 ) ? ValidationResult.Success: new ValidationResult("Is out of range"); return result; } }

12. CustomValidation Attribute [MetadataTypeAttribute( typeof( Employee.EmployeeMetadata ) )] publicpartialclassEmployee } internalsealedclassEmployeeMetadata } [CustomValidation( typeof(MyValidator) , "ValidationAddress")] public short AddressNum { get; set; } } }

13. Custom Validation Attribute Derived from ValidationAttributein order to have library of custom validation attributes. public class EvenNumberAttribute : ValidationAttribute{ protected override ValidationResult IsValid( object value , ValidationContext validationContext ) { return ( (short) value % 2 == 0 ? ValidationResult.Success : new ValidationResult("...") ); } }

14. Client-Side Validation

15. Client-Side Validation <script src="@Url.Content("~/jquery1.4.4.min.js")" type="text/javascript" /><script src="@Url.Content("~/jquery.validate.min.js")" type="text/javascript"/> <script src="@Url.Content("~/jquery.validate.unobtrusive.min.js")" ... /> @HtmlHelper.EnableClientValidation = true; // By default define in config file. @using (Html.BeginForm()) { @Html.ValidationSummary(true) <fieldset> <legend>TimeCard</legend> <div class="editor-label"> @Html.LabelFor(model => model.Username) </div> <div class="editor-field"> @Html.EditorFor(model => model.Username) @Html.ValidationMessageFor(model => model.Username) </div> </fieldset> }

16. public class Contact{ [StringLength(4)] public string Name { get; set; }} Model <div class="editor-field"> @Html.TextBoxFor(m => m.Name) @Html.ValidationMessageFor(m => m.Name)</div> View <div class="editor-field"> <input name="Name" id="Name"type="text" value="" data-val="true | false" data-val-length="Error Message" data-val-length-max="4" /> <span class="field-validation-valid" data-valmsg-for="Name" data-valmsg-replace="true | false" /></div> <div class="editor-field"> <input name="Name" id="Name"type="text" value="" /> <span class="field-validation-valid" /></div> <div class="editor-field"> <input name="Name" id="Name"type="text" value="" data-val="true | false" data-val-length="Error Message" data-val-length-max="4" /> <span class="field-validation-valid" /></div> HTML Client Attribute

17. IClientValidatable Enables MVC to discover at run time whether a validator has support for client validation. public sealed class DateRangeAttribute : ValidationAttributeIClientValidatable{ public IEnumerable<ModelClientValidationRule> GetClientValidationRules( ModelMetadata metadata, ControllerContext context) { return new[]{ new ModelClientValidationRangeDateRule( FormatErrorMessage( metadata.GetDisplayName() ), _minDate, _maxDate) }; } }

18. public class ModelClientValidationRangeDateRule : ModelClientValidationRule { public ModelClientValidationRangeDateRule( string errorMessage, DateTime minValue, DateTime maxValue) { ErrorMessage = errorMessage; ValidationType = "rangedate"; ValidationParameters["min"] = minValue.ToString("yyyy/MM/dd"); ValidationParameters["max"] = maxValue.ToString("yyyy/MM/dd"); } } <input id="Foo_Date"class="date" name="Foo.Date" type="text" value="…" data-val="true" data-val-rangedate="Error Message" data-val-rangedate-max="2010/12/20" data-val-rangedate-min="2010/12/02" data-val-required="The Date field is required." /> <span class="field-validation-valid" data-valmsg-for="Foo.Date" data-valmsg-replace="true" />

19. JQuery Date Range Validation (function ($) { $.validator.addMethod('rangeDate', function (value, element, param){ if(!value) returntrue; try{ vardateValue = $.datepicker.parseDate("dd/mm/yy", value); } catch(e) { return false; } returnparam.min <= dateValue && dateValue <= param.max; }); // The adapter to support ASP.NET MVC unobtrusive validation $.validator.unobtrusive.adapters.add('rangedate', ['min', 'max'], function(options) { varparams = { min: $.datepicker.parseDate("yy/mm/dd", options.params.min), max: $.datepicker.parseDate("yy/mm/dd", options.params.max) }; options.rules['rangeDate'] = params; if (options.message) { options.messages['rangeDate'] = options.message; } }); } (jQuery));

20. JQuery Date Range Validation $(document).ready( function () { function getDateYymmdd(value) { if (value == null) return null; return $.datepicker.parseDate("yy/mm/dd", value); } $('.date').each( function () { var minDate = getDateYymmdd( $(this).data("val-rangedate-min")); var maxDate = getDateYymmdd( $(this).data("val-rangedate-max")); $(this).datepicker( { dateFormat: "dd/mm/yy", minDate : minDate, maxDate : maxDate }); }); });

21. IClientValidatable

22. Remote Validator Remote Validator JQuery publicclassContact { [Remote("UserNameAvailable", "My")] publicstringUserName { get; set; } } Model public JsonResult UserNameAvailable(string username) { if (MyRepository.UserNameExists(username)) ... return Json( “message” , JsonRequestBehavior.AllowGet);} MyController <input ... data-val-remote="UserName is invalid." data-val-remote-additionalfields="*.UserName" data-val-remote-url="/Validation/IsUID_Available" />

23. Remote Validator

24. Summary New validation features Data annotations & ValidationContext Self validation, IValidatebleObject Client validation Remote validation Unobtrusive client validation