implement search screen using knockoutjs

Implement Search screen using knockoutjs, Jquery and asp.net mvc3

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Neeraj Kaushik

This article demonstrates implementation of knockoutjs observable viewmodel and how to bind viewmodel with html controls.

http://dotnetdlr.com/2012/03/28/implement-search-screen-using-knockoutjs-jquery-and-asp-net-mvc3-2/

Here I am trying to explain steps for how to use knockoutjs viewmodel, jquery ajax request in asp.net mvc3 project.

I am taking practical example to show 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 flow of information across different layers:

Let’s start implementation.

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}); }

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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 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

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</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 is bind 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 java script file. This viewmodel also has search function which sends ajax request to “Search” action method on server and receive 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",

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success: function (response) { //bind data self.employees(response.Items); self.DeptId(response.DeptId); } });

}}

Output

You can find code here.

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implement search screen using knockoutjs

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