Understanding MVC Validation with an Example
In this example, we will use annotations. The order that we follow in this example is: First, we will create the controller, then the model, and after that, the view followed by output.
Controller
This is the syntax for creating a controller. Here we are creating a student controller:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
namespace MvcApplicationDemo.Controllers
{
public class StudentsController : Controller
{
// GET: Students
public ActionResult Index()
{
return View();
}
}
}
Model
Here we are creating a student model:
using System.ComponentModel.DataAnnotations;
namespace MvcApplicationDemo.Models
{
public class Student
{
public int ID { get; set; }
// -- Validating Student Name
[Required(ErrorMessage ="Name is required")]
[MaxLength(12)]
public string Name { get; set; }
// -- Validating Contact Number
[Required(ErrorMessage = "Contact is required")]
[DataType(DataType.PhoneNumber)]
[RegularExpression(@"^\(?([0-9]{3})\)?[-. ]?([0-9]{3})[-. ]?([0-9]{4})$", ErrorMessage = "Not a valid Phone number")]
public string Contact { get; set; }
// -- Validating Email Address
[Required(ErrorMessage ="Email is required")]
[EmailAddress(ErrorMessage = "Invalid Email Address")]
public string Email { get; set; }
}
}
View
Now this will be the view that is visible to the user on the front end:
@model MvcApplicationDemo.Models.Student
@{
ViewBag.Title = "Index";
}
<h2>Index</h2>
@using (Html.BeginForm())
{
@Html.AntiForgeryToken()
<div class="form-horizontal">
<h4>Student</h4>
<hr />
@Html.ValidationSummary(true, "", new { @class = "text-danger" })
<div class="form-group">
@Html.LabelFor(model => model.Name, htmlAttributes: new { @class = "control-label col-md-2" })
<div class="col-md-10">
@Html.EditorFor(model => model.Name, new { htmlAttributes = new { @class = "form-control" } })
@Html.ValidationMessageFor(model => model.Name, "", new { @class = "text-danger" })
</div>
</div>
<div class="form-group">
@Html.LabelFor(model => model.Contact, htmlAttributes: new { @class = "control-label col-md-2" })
<div class="col-md-10">
@Html.EditorFor(model => model.Contact, new { htmlAttributes = new { @class = "form-control" } })
@Html.ValidationMessageFor(model => model.Contact, "", new { @class = "text-danger" })
</div>
</div>
<div class="form-group">
@Html.LabelFor(model => model.Email, htmlAttributes: new { @class = "control-label col-md-2" })
<div class="col-md-10">
@Html.EditorFor(model => model.Email, new { htmlAttributes = new { @class = "form-control" } })
@Html.ValidationMessageFor(model => model.Email, "", new { @class = "text-danger" })
</div>
</div>
<div class="form-group">
<div class="col-md-offset-2 col-md-10">
<input type="submit" value="Create" class="btn btn-default" />
</div>
</div>
</div>
}
<div>
@Html.ActionLink("Back to List", "Index")
</div>
@section Scripts {
@Scripts.Render("~/bundles/jqueryval")
}
Output
We can see in the below attached screenshot that it validates the empty fields and displays the message that these fields are required.
In the below-attached screenshot, we are validating the entered data.
Frequently Asked Questions
1. Write some features of ASP.NET.
Answer: It can separate server-side code with the HTML layout and uses C# and VB.NET as languages to make the website.
2. What is a round trip?
Answer: It is the trip of a web page from client to server and then again from server to client.
3. Name some page events in ASP.NET.
Answer: Some page events in ASP.NET are preinit, init, PreLoad, Load, Render, PreRender, etc.
4. How many types of validations are there in ASP.NET?
Answer: There are mainly two validations in ASP.NET: client-side and server-side.
Key Takeaways
In this blog, we have learned about MVC validations by explaining the base class validator, the standard annotations used during validation, and examples with Model, View, Controller.
If you want to learn about Webform LinkButton in ASP.Net, look at this blog. Here, you will get the idea of what they are and the Features Of ASP Net with examples.
Recommended Readings:
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