Simple Validations

In this type we will see how to use model state and the validation HTML helpers

Class

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

namespace MvcTextApplication.Models

{

public class Person

{

public int Id { get; set; }

public string Name { get; set; }

public int Age { get; set; }

public string email { get; set; }

public DateTime DOB { get; set; }

}

Controller:

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Web.Mvc;

using MvcTextApplication.Models;

namespace MvcTextApplication.Controllers

{

public class PersonController : Controller

{

List<Person> people = new List<Person>();

public ActionResult Index()

{

Person per= new Person();

per.Id = 1;

per.Name = "Guugeaaa";

per.email = "Sample@gmail.com";

per.DOB = DateTime.Now;

people.Add(per);

List<Person> fundlistnew;

fundlistnew = people;

var movies = fundlistnew;

return View(movies.ToList());

}

NOTE: Create View by right click on this Action method

public ActionResult Create()

{

return View();

}

[AcceptVerbs(HttpVerbs.Post)]

public ActionResult Create([Bind(Exclude = "Id")] Person person)

{

// Validation logic

if (person.Name == null)

ModelState.AddModelError("Name", "Name is required not null.");

if (person.Age == null)

ModelState.AddModelError("Age", "Age is required.");

if (person.DOB == null)

ModelState.AddModelError("DOB", "DOB is required.");

if (person.email == null)

{

ModelState.AddModelError("Email", "Email is required.");

}

else

{

if (!System.Text.RegularExpressions.Regex.IsMatch(person.email, @"^[\w-\.]+@([\w-]+\.)+[\w-]{2,4}$"))

{

ModelState.AddModelError("Email", "Email format is invalid.");

}

//ModelState.IsValid to check whether the Person has any validation errors.

// Calling this method evaluates any validation attributes that have been applied to the object.

// If the object has validation errors, the Create method redisplays the form.

if (!ModelState.IsValid)

{

return View("Create", person);

}

//people.Add(person);

return RedirectToAction("Index");

}

HTML

Index Action method View

<p>

<%: Html.ActionLink("Create New", "Create") %>

</p>

<table>

<tr>

<th></th> <th>Name</th><th> Age</th> <th> email</th> <th>DOB</th>

</tr>

<% foreach (var item in Model) { %>

<tr>

<td>

<%: String.Format("{0:g}", item.DOB) %>

</td>

</tr>

<% } %>

</table>

Create Action method View

<h2>Create</h2>

<%= Html.ValidationSummary("Create was unsuccessful. Please correct the errors and try again.") %>

</ul>

<% using (Html.BeginForm()) { %>

<legend>Person</legend>

<%: Html.LabelFor(model => model.Name) %>

</div>

<%: Html.EditorFor(model => model.Name) %>

<%: Html.ValidationMessage("Name","*") %>

</div>

<%: Html.LabelFor(model => model.Age) %>

</div>

<%: Html.EditorFor(model => model.Age) %>

<%: Html.ValidationMessage("Age", "*") %>

</div>

<%: Html.LabelFor(model => model.email) %>

</div>

<%: Html.EditorFor(model => model.email) %>

<%: Html.ValidationMessage("Email", "*")%>

</div>

<%: Html.LabelFor(model => model.DOB) %>

</div>

<%: Html.EditorFor(model => model.DOB) %>

<%: Html.ValidationMessage("DOB", "*")%>

</div>

<p>

</p>

</fieldset>

<% } %>

<div>

<%: Html.ActionLink("Back to List", "Index") %>

</div>

OUTPUT

Note: Html.ValidationMessage is used when we need to show error message as validation summary for that we must include <%= Html.ValidationSummary()%> otherwise error will not shown or we need to replace Html.ValidationMessage with Html.ValidationMessagefor to show inline error messages. Here we passed a lambda expression that specifies the Address property. In this case we do not need to explicitly specify name/id of the helper method will take it from the property name

e.g. <%: Html.ValidationMessageFor(model => model.Name) %>

Validations Using Data Annotation Validators

System.ComponentModel.DataAnnotations namespace to specify validation for individual fields in the data model. These attributes define common validation patterns, such as range checking and required fields.

The advantage of using the Data Annotation validators is that they enable you to perform validation simply by adding one or more attributes

Class :

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.ComponentModel.DataAnnotations;

namespace MvcTextApplication.Models

{

public class PersonType

{

public int Id { get; set; }

[Required(ErrorMessage = "Name is required")]

[StringLength(10)]

[Display(Name = "PersonName")]

public string Name { get; set; }

[Required(ErrorMessage = "Age is required")]

[Range(15, 35, ErrorMessage = "Age must be between 15 and 35")]

[Display(Name = "PersonAge")]

public int Age { get; set; }

[Required(ErrorMessage = "Email is required")]

[RegularExpression(@"^[\w-\.]+@([\w-]+\.)+[\w-]{2,4}$", ErrorMessage = "Invalid Email Address")]

public string email { get; set; }

[Required(ErrorMessage = "DOB is required")]

[DisplayFormat(DataFormatString = "{0:c}")]

[Display(Name = "DateOfBirth")]

[RegularExpression(@"(0[1-9]|[12][0-9]|3[01])[- /.](0[1-9]|1[012])[- /.](19|20)\d\d", ErrorMessage = "Invalid date e.g. 17/04/1981")]

public DateTime DOB { get; set; }

}

Note : In above class attribute [Display(Name = "")] will display Text on Create Page shown in fig below e.g. property Name will be displayed as PersonName.

Controller :

using System.Web.Mvc;

using MvcTextApplication.Models;

namespace MvcTextApplication.Controllers

{

public class PersonTypeController : Controller

{

List<PersonType> people = new List<PersonType>();

// GET: /Person/

public ActionResult Index()

{

PersonType per = new PersonType();

per.Id = 1;

per.Name = "Guggeaaa";

per.Age = 30;

per.email = "Sample@gmail.com";

per.DOB = DateTime.Now;

people.Add(per);

List<PersonType> fundlistnew;

fundlistnew = people;

var objperson = fundlistnew;

return View(objperson.ToList());

}

NOTE: Create View by right click on this Action method

public ActionResult Create()

{

return View();

}

NOTE: Don’t Create View from this Action method this method comes into action on postback

[AcceptVerbs(HttpVerbs.Post)]

public ActionResult Create(PersonType person)

{

// When our HTML form is posted back to the server, the this method will be called. Because the action method accepts a “Person” //object as a parameter, ASP.NET MVC will create a Person object and automatically map the incoming form input values to it.

// it will also check to see whether the DataAnnotation validation attributes for the Person object are valid.

//If everything is valid, then the ModelState.IsValid check within our code will redirect to Index Action method otherwise errors .

// The error messages are then displayed within our view because our Create form has <%= Html.ValidationMessageFor() %> helper method calls next to each <%= Html.TextBoxFor() %> helper.

if (!ModelState.IsValid)

{

return View("Create", person);

}

////people.Add(person);

return RedirectToAction("Index");

}

HTML:

Index Action method View

<h2>Index</h2>

<p>

<%: Html.ActionLink("Create New", "Create") %>

</p>

<table>

<tr>

<th>Name</th><th> Age</th> <th> email </th> <th> DOB </th>

</tr>

<% foreach (var item in Model) { %>

<tr>

<td>

<%: Html.ActionLink("Edit", "Edit", new { id=item.Id }) %> |

<%: Html.ActionLink("Details", "Details", new { id=item.Id }) %> |

<%: Html.ActionLink("Delete", "Delete", new { id=item.Id }) %>

</td>

</tr>

<% } %>

</table>

Create Action method View

<h4>Create</h4>

<% using (Html.BeginForm()) { %>

<legend>PersonType</legend>

<%: Html.LabelFor(model => model.Name) %>

</div>

<%: Html.EditorFor(model => model.Name) %>

<%: Html.ValidationMessageFor(model => model.Name) %>

</div>

<%: Html.LabelFor(model => model.Age) %>

</div>

<%: Html.EditorFor(model => model.Age) %>

<%: Html.ValidationMessageFor(model => model.Age) %>

</div>

<%: Html.LabelFor(model => model.email) %>

</div>

<%: Html.EditorFor(model => model.email) %>

<%: Html.ValidationMessageFor(model => model.email) %>

</div>

<%: Html.LabelFor(model => model.DOB) %>

</div>

<%: Html.EditorFor(model => model.DOB) %>

<%: Html.ValidationMessageFor(model => model.DOB) %>

</div>

<p>

</p>

</fieldset>

<% } %>

<div>

<%: Html.ActionLink("Back to List", "Index") %>

</div>

OutPut

**************************************************

**************************************************

Custom Annotations Validation Attribute :

Create CheckAgeAttribute Class IN Model Folder. In this class we are checking age of person.where CheckAge is attribute name

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.ComponentModel.DataAnnotations;

public class CheckAgeAttribute : ValidationAttribute

{

private int _maxAGE;

public CheckAgeAttribute(int MaxAge)

{

_maxAGE = MaxAge;

}

public override bool IsValid(object value)

{

if (value == null) return true;

var dateofbirth = (DateTime)value;

double AgeValue = DateTime.Now.Subtract(dateofbirth).TotalDays / 365;

if (AgeValue < _maxAGE) return false;

return true;

}

Let’s take above class Person Type

public class PersonType

{

public int Id { get; set; }

[Required(ErrorMessage = "Name is required")]

[StringLength(10)]

[Display(Name = "PersonName")]

public string Name { get; set; }

[Required(ErrorMessage = "Age is required")]

[Range(15, 35, ErrorMessage = "Age must be between 15 and 35")]

[Display(Name = "PersonAge")]

public int Age { get; set; }

[Required(ErrorMessage = "Email is required")]

[RegularExpression(@"^[\w-\.]+@([\w-]+\.)+[\w-]{2,4}$", ErrorMessage = "Invalid Email Address")]

public string email { get; set; }

[Required(ErrorMessage = "DOB is required")]

[DisplayFormat(DataFormatString = "{0:c}")]

[Display(Name = "DateOfBirth")]

[CheckAge(18,ErrorMessage="You are not 18 years older" ) ]

public DateTime DOB { get; set; }

}

Out Put:

Enabling Client-side Validation

Just put Three highlighted yellow Lines at top of page

<h4>Create</h4>

<% Html.EnableClientValidation();%>

<% using (Html.BeginForm()) { %>

<legend>PersonType</legend>

<%: Html.LabelFor(model => model.Name) %>

</div>

<%: Html.EditorFor(model => model.Name) %>

<span class="validation-summary-error"> <%: Html.ValidationMessageFor(model => model.Name) %></span>

</div>

<%: Html.LabelFor(model => model.Age) %>

</div>

<%: Html.EditorFor(model => model.Age) %>

<span class="validation-summary-error"> <%: Html.ValidationMessageFor(model => model.Age) %></span>

</div>

<%: Html.LabelFor(model => model.email) %>

</div>

<%: Html.EditorFor(model => model.email) %>

<span class="validation-summary-error"> <%: Html.ValidationMessageFor(model => model.email) %></span>

</div>

<%: Html.LabelFor(model => model.DOB) %>

</div>

<%: Html.EditorFor(model => model.DOB) %>

<span class="validation-summary-error"> <%: Html.ValidationMessageFor(model => model.DOB) %></span>

</div>

<p>

</p>

</fieldset>

<% } %>

<div>

<%: Html.ActionLink("Back to List", "Index") %>

</div>

Validations with the IDataErrorInfo Interface :

Class :

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.ComponentModel.DataAnnotations;

using System.ComponentModel;

namespace MvcTextApplication.Models

{

public partial class Employee : IDataErrorInfo

{

private string _firstName;

private string _email;

private Dictionary<string, string> _errors = new Dictionary<string, string>();

public string FirstName {

get { return _firstName; }

set {

if (String.IsNullOrEmpty(value))

_errors.Add("FirstName", "First Name is required");

_firstName = value;

}

public string Email

{

get { return _email; }

set

{

if (String.IsNullOrEmpty(value))

{

_errors.Add("Email", "Email is required");

}

else

{

if (!System.Text.RegularExpressions.Regex.IsMatch(value, @"^[\w-\.]+@([\w-]+\.)+[\w-]{2,4}$"))

{

_errors.Add("Email", "Email format is invalid.");

}

_email = value;

}

public string Error

{

get { return String.Empty; }

}

public string this[string columnName]

{

get {

if (_errors.ContainsKey(columnName))

return _errors[columnName];

return String.Empty;

}

Model :

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.ComponentModel.DataAnnotations;

using System.ComponentModel;

namespace MvcTextApplication.Models

{

public partial class Employee : IDataErrorInfo

{

private string _firstName;

private string _email;

private Dictionary<string, string> _errors = new Dictionary<string, string>();

public string FirstName {

get { return _firstName; }

set {

if (String.IsNullOrEmpty(value))

_errors.Add("FirstName", "First Name is required");

_firstName = value;

}

public string Email

{

get { return _email; }

set

{

if (String.IsNullOrEmpty(value))

{

_errors.Add("Email", "Email is required");

}

else

{

if (!System.Text.RegularExpressions.Regex.IsMatch(value, @"^[\w-\.]+@([\w-]+\.)+[\w-]{2,4}$"))

{

_errors.Add("Email", "Email format is invalid.");

}

_email = value;

}

public string Error

{

get { return String.Empty; }

}

public string this[string columnName]

{

get {

if (_errors.ContainsKey(columnName))

return _errors[columnName];

return String.Empty;

}

Controller :

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Web.Mvc;

using MvcTextApplication.Models;

namespace MvcTextApplication.Controllers

{

public class EmaployeeController : Controller

{

// GET: /Emaployee/

public ActionResult Create()

{

return View();

}

[AcceptVerbs(HttpVerbs.Post)]

public ActionResult Create(Employee emp)

{

if (!ModelState.IsValid)

{

return View("Create", emp);

}

////people.Add(person);

return RedirectToAction("Index");

}

View:

<h2>Create</h2>

<% using (Html.BeginForm()) { %>

<%: Html.ValidationSummary(true) %>

<legend>Employee</legend>

<%: Html.LabelFor(model => model.FirstName) %>

</div>

<%: Html.EditorFor(model => model.FirstName) %>

<span class="validation-summary-error"> <%: Html.ValidationMessageFor(model => model.FirstName) %></span>

</div>

<%: Html.LabelFor(model => model.Email) %>

</div>

<%: Html.EditorFor(model => model.Email) %>

<span class="validation-summary-error"> <%: Html.ValidationMessageFor(model => model.Email) %></span>

</div>

<p>

</p>

</fieldset>

<% } %>

<div>

<%: Html.ActionLink("Back to List", "Index") %>

</div>

OutPut:

Play With Coding Techniques

Tuesday, June 5, 2012

MVC- Validations

Validations Using Data Annotation Validators

Custom Annotations Validation Attribute :

Validations with the IDataErrorInfo Interface :

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