Implement Search Screen using knockoutjs, jQuery, and ASP.NET MVC3

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Introduction

Here, I am trying to give steps for how to use knockoutjs viewmodel, jQuery AJAX request in an ASP.NET MVC3 project.

I am taking a practical example to show this behaviour. This example will have simple UI screen with search textbox and button. When click on search button, AJAX request will go to server and will call action method of controller class which will return results in json format, then we will see how json result will bind to viewmodel and HTML controls.

Following is the flow of information across the different layers:

Implementation

Model

Create model class Employee.

class Employee
    {
        public int EmployeeID { get; set; }
        public string Name { get; set; }
        public string Address { get; set; }
        public string Phone { get; set; }
        public string Dept { get; set; }
    } 

Controller

• Create Controller class in controller folder, i.e., EmployeeController
• Implement Action method “Search” which will search on empname.

public JsonResult Search(string EmpName)
        {
            var emplist = PrepareEmpList();

            var searchedlist= from emp in emplist
                            where emp.Name.Contains(EmpName)
                            select emp;

            return Json(new { Items = searchedlist});
        }

        private static List PrepareEmpList()
        {
            var emplist = new List();
            //create list of employee
            for (int i = 0; i < 20; i++)
            {
                var emp = new Employee();
                emp.EmployeeID = i;
                emp.Name = string.Format("Employee-{0}", i);
                emp.Address = string.Format("ABC New Delhi- 1{0}", i);
                if (i % 2 == 0)
                    emp.Dept = "IT";
                else
                    emp.Dept = "Admin";

                emplist.Add(emp);
            }
            return emplist;
        }

In the above code, controller has action method “Search” which has code to search on supplied search condition and send back result in json object.

View

@{
    ViewBag.Title = "Employee Search";
    Layout = "~/Views/Shared/_Layout.cshtml";
}
@section head{
<script src="../Scripts/knockout-2.0.0.js"></script>
}

<h2>
    Employee List</h2>

<div>
Search:<input type="text" data-bind="value:empname" />

<input type="button" id='btnSearch' title="Search" value="Search"/>
</div>

<table style="border-style:solid;border-width:1px">
    <thead style="background-color:Gray">
        <tr>
            <th>
                ID
            </th>
            <th>
                Name
            </th>
             <th>
                Address
            </th>
            <th>
                Phone
            </th>
        </tr>
    </thead>
    <tbody data-bind="foreach: employeemodel.employees">
        <tr>
            <td data-bind="text: EmployeeID">
            </td>
            <td data-bind="text: Name">
            </td>
        </tr>
    </tbody>
</table>

<input type="text" data-bind="value:empname" />

This is input text box which binds to empname property of knockoutjs viewmodel which is defined in JavaScript file.

<tbody data-bind="foreach: employeemodel.employees">

This will use for looping in viewmodel’s observable collection.

Note: “data-bind” attribute is used to bind knockoutjs viewmodel.

View Model

Viewmodel is defined in JavaScript file. This viewmodel also has a search function which sends an AJAX request to the Search action method on the server and receives JSON result.

Employee.js

var employeemodel;
$(document).ready(function () {

    //initializing viewmodel
    employeemodel = new viewModel();
    //binding for ko
    ko.applyBindings(employeemodel);
    //bind event
    $("#btnSearch").click({ handler: employeemodel.search });
    //call search method
    //employeemodel.search();

});

function viewModel() {
    var self = this;
    self.employees = ko.observableArray([]);
    self.empname = ko.observable('');
    self.search = function () {
        $.ajax({
            url: "Employee/Search",
            data: { EmpName: self.empname },
            type: "POST",
            success: function (response) {
                //bind data
                self.employees(response.Items);
            }
        });
    }
}

Output