When it comes to developing a web or mobile application , data validation plays a very important role in our application.In Asp.net we can easily apply validation to web application by using Data Annotation attribute classes to model class.

Data Annotation attribute classes are available in System.ComponentModel.DataAnnotations namespace and this namespace is availlable to Asp.net projects like Asp.net web application & website ,if not available you can easily add referance for this namespace by searching .

Data Annotations help us to define the rules to the model classes or properties for data validation and displaying suitable messages to end users.

Data Annotation Validator Attributes

 

DataType
Specify the datatype of a property

DisplayName
specify the display name for a property.

DisplayFormat
specify the display format for a property like different format for Date proerty.

Required
Specify a property as required.

ReqularExpression
validate the value of a property by specified regular expression pattern.

Range
validate the value of a property with in a specified range of values.

StringLength
specify min and max length for a string property.

MaxLength
specify max length for a string property.

Bind
specify fields to include or exclude when adding parameter or form values to model properties.

ScaffoldColumn
specify fields for hiding from editor forms.

Designing the model with Data Annotation

  1. using System.ComponentModel;
  2. using System.ComponentModel.DataAnnotations;
  3. using System.Web.Mvc;
  4. namespace Employee.Models
  5. {
  6. [Bind(Exclude = “EmpId”)]
  7. public class Employee
  8. {
  9. [ScaffoldColumn(false)]
  10. public int EmpId { get; set; }
  11. [DisplayName(“Employee Name”)]
  12. [Required(ErrorMessage = “Employee Name is required”)]
  13. [StringLength(100,MinimumLength=3)]
  14. public String EmpName { get; set; }
  15. [Required(ErrorMessage = “Employee Address is required”)]
  16. [StringLength(300)]
  17. public string Address { get; set; }
  18. [Required(ErrorMessage = “Salary is required”)]
  19. [Range(3000, 10000000,ErrorMessage = “Salary must be between 3000 and 10000000”)]
  20. public int Salary{ get; set; }
  21. [Required(ErrorMessage = “Please enter your email address”)]
  22. [DataType(DataType.EmailAddress)]
  23. [Display(Name = “Email address”)]
  24. [MaxLength(50)]
  25. [RegularExpression(@“[a-z0-9._%+-]+@[a-z0-9.-]+\.[a-z]{2,4}”, ErrorMessage = “Please enter correct email”)]
  26. public string Email { get; set; }
  27. }
  28. }

Once we have define validation to the model by using data annotations, these are automatically used by Html Helpers in views. For client side validation to work, please ensure that below two <SCRIPT> tag references are in the view.

  1. <script src=“@Url.Content(“~/Scripts/jquery.validate.min.js“)” type=“text/javascript”></script>
  2. <script src=“@Url.Content(“~/Scripts/jquery.validate.unobtrusive.min.js“)” type=“text/javascript”></script>

Presenting the model in the view

  1. @model Employee.Models
  2. @{
  3. ViewBag.Title = “Employee Details”;
  4. Layout = “~/Views/Shared/_Layout.cshtml”;
  5. }
  6. @using (Html.BeginForm())
  7. {
  8. <div class=“editor-label”>
  9. @Html.LabelFor(m => m.EmpName)
  10. </div>
  11. <div class=“editor-field”>
  12. @Html.TextBoxFor(m => m.EmpName)
  13. @Html.ValidationMessageFor(m => m.EmpName)
  14. </div>
  15. <div class=“editor-label”>
  16. @Html.LabelFor(m => m.Address)
  17. </div>
  18. <div class=“editor-field”>
  19. @Html.TextBoxFor(m => m.Address)
  20. @Html.ValidationMessageFor(m => m.Address)
  21. </div>
  22. <div class=“editor-label”>
  23. @Html.LabelFor(m => m.Salary)
  24. </div>
  25. <div class=“editor-field”>
  26. @Html.TextBoxFor(m => m.Salary)
  27. @Html.ValidationMessageFor(m => m.Salary)
  28. </div>
  29. <div class=“editor-label”>
  30. @Html.LabelFor(m => m.Email)
  31. </div>
  32. <div class=“editor-field”>
  33. @Html.TextBoxFor(m => m.Email)
  34. @Html.ValidationMessageFor(m => m.Email)
  35. </div>
  36. <p> <input type=“submit” value=“Save” />
  37. </p>
  38. }

Controller

[HttpPost]
public ActionResult Add_Employee( Employee e)
{

if (ModelState.IsValid)
{
// your database logic code
}
return View();
}

Summary

In this blog I try to expose the Data Annotations with example. for any query you can comment below

 

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