Single Page Application Using KNOCKOUT ASP.NET

Surya Prakash
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In this article, I will discuss how to create a sample single-page application using KNOCKOUT & ASP.NET. This application shows a list of users based on types like Users, Admin Users, Super Admin Users & shows user details upon selection of a user.

For building this app, one should have basic knowledge of KNOCKOUT, the SAMMY library, WCF Restful Services and JavaScript.

Before we jump into the article let's have a look at the standard definition of KNOCKOUT.

Knockout is a JavaScript library that helps you to create rich, responsive display and editor user interfaces with a clean underlying data model. Any time you have sections of UI that update dynamically (e.g., changing depending on the user's actions or when an external data source changes), KO can help you implement it more simply and maintainably.

Sammy.js is an excellent lightweight routing JavaScript library. You can do things like this to route when used in pair with Knockout (from the tutorials web site or KnockoutJS):

Create WCF Restful Service
Create ASP.NET web site
Define ViewModel
Define View
Define Styles
Output screen

1. Create WCF Restful Service

We will define two methods:

GetUsers: returns a list of users based on usertype
GetUserData: returns a list of users based on userid & usertype

These services would return a JSON object. Here is the code below. To know more about how to build a restful service, see my article at http://www.codeproject.com/Articles/275279/Developing-WCF-Restful-Services-with-GET-and-POST

I have defined my service as ServiceOne.svc, so my interface would we something like this:

[ServiceContract]
    public interface IServiceOne
    {
        [OperationContract(Name = "GetUsers")]
        [WebInvoke(Method = "GET", UriTemplate = "GetUsers/utypeid/{userTypeId}", RequestFormat = WebMessageFormat.Json,
           ResponseFormat = WebMessageFormat.Json)]

myCustomObject GetUsers(string userTypeId);

        [OperationContract(Name = "GetUserData")]
        [WebInvoke(Method = "GET", UriTemplate = "GetUserData/utypeid/{userTypeId}/uid/{userId}", RequestFormat = WebMessageFormat.Json,
           ResponseFormat = WebMessageFormat.Json)]

users GetUserData(string userTypeId, string userid);

    }

Also, to work on this I define two classes, named myCustomObject and users.

Here is the definition for them:

    public class myCustomObject
    {
        public string userTypeId { get; set; }

public List<users> users { get; set; }

}

    public class users
    {
        public string userid { get; set; }

public string usertypeid { get; set; }

public string firstname { get; set; }

public string lastname { get; set; }

public string address { get; set; }

}

The following is the implementation for the methods defined in the interface. I have avoided use of a DB since this is a sample, so I have just defined static values.

public class ServiceOne : IServiceOne

{

public myCustomObject GetUsers(string userTypeId)

{

myCustomObject myObj = new myCustomObject();

myObj.userTypeId = userTypeId;

List<users> usersList = new List<users>();

if (userTypeId == "Users")

{

usersList.Add(new users() { usertypeid = "Users", userid = "1", firstname = "user fname 1", lastname = "user lname 1", address = "user address 1" });

usersList.Add(new users() { usertypeid = "Users", userid = "2", firstname = "user fname 2", lastname = "user lname 2", address = "user address 2" });

}

else if (userTypeId == "AdminUsers")

{

usersList.Add(new users() { usertypeid = "AdminUsers", userid = "3", firstname = "admin user fname 1", lastname = "admin user lname 1", address = "admin user address 1" });

usersList.Add(new users() { usertypeid = "AdminUsers", userid = "4", firstname = "admin user fname 2", lastname = "admin user lname 2", address = "admin user address 2" });

}

else if (userTypeId == "SuperAdminUsers")

{

usersList.Add(new users() { usertypeid = "SuperAdminUsers", userid = "5", firstname = "super admin user fname 1", lastname = "super admin user lname 1", address = "super admin user address 1" });

usersList.Add(new users() { usertypeid = "SuperAdminUsers", userid = "6", firstname = "super admin user fname 2", lastname = "super admin user lname 2", address = "super admin user address 2" });

}

myObj.users = usersList;

return myObj;

}

public users GetUserData(string userTypeId, string userid)

{

List<users> usersList = new List<users>();

usersList.Add(new users() { usertypeid = "Users", userid = "1", firstname = "user fname 1", lastname = "user lname 1", address = "user address 1" });

usersList.Add(new users() { usertypeid = "Users", userid = "2", firstname = "user fname 2", lastname = "user lname 2", address = "user address 2" });

usersList.Add(new users() { usertypeid = "AdminUsers", userid = "3", firstname = "admin user fname 1", lastname = "admin user lname 1", address = "admin user address 1" });

usersList.Add(new users() { usertypeid = "AdminUsers", userid = "4", firstname = "admin user fname 2", lastname = "admin user lname 2", address = "admin user address 2" });

usersList.Add(new users() { usertypeid = "SuperAdminUsers", userid = "5", firstname = "super admin user fname 1", lastname = "super admin user lname 1", address = "super admin user address 1" });

usersList.Add(new users() { usertypeid = "SuperAdminUsers", userid = "6", firstname = "super admin user fname 2", lastname = "super admin user lname 2", address = "super admin user address 2" });

users obj = (from user in usersList.Where(val => val.userid == userid && val.usertypeid == userTypeId)

select user).First();

return obj;

}

Host your service in IIS & test it by using the URL; in my case it is as follows:

http://localhost/wcfrestservice/ServiceOne.svc/GetUsers/id/Users

By clicking it, you should be able to JSON object. Make sure that you don't run your application using Port No.

2. Create ASP.NET web site

Create an ASP.Net web site & add a new webpage name, userslist.aspx.

By this time you must understand that KnockOut follows a MVVM pattern i.e. Model, View, ViewModel pattern.

a. Add the following script reference to your page:


<script type="text/javascript" src="http://learn.knockoutjs.com/Scripts/CDNHosted/jquery-1.7.1.min.js"></script>

<script type="text/javascript" src="http://learn.knockoutjs.com/Scripts/Lib/knockout-2.1.0.js"></script>

<script src="http://learn.knockoutjs.com/scripts/lib/sammy.js" type="text/javascript"></script>

3. Define ViewModel

Let's add the following script code to the page; see the inline code comments:

<script type="text/javascript">
          function UsersViewModel() {
              // Data
              var self = this;

// defines usertypes
self.userTypes = ['Users', 'AdminUsers', 'SuperAdminUsers'];

// holds usertypeid, when usertype is selected
self.chosenuserTypeId = ko.observable();

// holds list of users for a selected usertype
self.chosenUserTypesData = ko.observable();

// hold userdata for a selected user
self.chosenUserData = ko.observable();

              // Behaviours
              self.goToUserType = function (usertypeid) { location.hash = usertypeid };
              self.goToUserData = function (userdata) { location.hash = userdata.usertypeid + '/' + userdata.userid };

// Client-side routes, can be defined by using SAMMY library
Sammy(function () {

// below segment is used to fetch userslist based on usertypeid
this.get('#:usertypeid', function () {

// sets selected usertypeid
self.chosenuserTypeId(this.params.usertypeid);

// destroy userdata, because at this point we need to have userslist instead of userdata
self.chosenUserData(null);

                      // make a call to wcf restful service, to fetchs users based on usertypeid
                      // response from service would contains "userslist", which is filled into chosenUserTypesData, whenever we statement "self.chosenUserTypesData"
                      $.get("http://localhost/wcfmailservice/ServiceOne.svc/GetUsers/Id/" + this.params.usertypeid, self.chosenUserTypesData);

});

// below segment is used to fetch userdata based on usertypeid & userid
this.get('#:usertypeid/:userid', function () {

// sets selected usertypeid
self.chosenuserTypeId(this.params.usertypeid);

// destroys userslist, because at this point we need to have userdata instead of userslist
self.chosenUserTypesData(null);

                      // make a call to wcf service, to fetch user data based on usertypeid & userid
                      $.get("http://localhost/wcfmailservice/ServiceOne.svc/GetUserData/utypeid/" + this.params.usertypeid + "/uid/" + this.params.userid, self.chosenUserData);
                  });

// when page load happens show default data, using sammy routing mechanism
this.get('', function () { this.app.runRoute('get', '#Users') });

}).run();

};

// allows to bind viewmodel defined above
ko.applyBindings(new UsersViewModel());

</script>

4. Define View

</ul>

<table class="userslist" data-bind="with: chosenUserTypesData">
        <thead><tr><th>First Name</th><th>Last Name</th><th>Address</th></tr></thead>
        <tbody data-bind="foreach: users">
            <tr data-bind="click: $root.goToUserData">
                <td data-bind="text: firstname"></td>
                <td data-bind="text: lastname"></td>
                <td data-bind="text: address"></td>
            </tr>
        </tbody>
    </table>

<div class="userData" data-bind="with: chosenUserData">
        <div class="userdetails">
            <p><label>First Name</label>: <span data-bind="text: firstname"></span></p>
            <p><label>Last Name</label>: <span data-bind="text: lastname"></span></p>

</div>
</div>

5. Define styles

.userTypes { background-color: #bbb; list-style-type: none; padding: 0; margin: 0; border-radius: 7px;

background-image: -webkit-gradient(linear, left top, left bottom, color-stop(0, #d6d6d6), color-stop(0.4, #c0c0c0), color-stop(1,#a4a4a4));

margin: 10px 0 16px 0;

font-size: 0px;

}

.userTypes li:hover { background-color: #ddd; }

.userTypes li:first-child { border-left: none; border-radius: 7px 0 0 7px; }

.userTypes li { font-size: 16px; font-weight: bold; display: inline-block; padding: 0.5em 1.5em; cursor: pointer; color: #444; text-shadow: #f7f7f7 0 1px 1px; border-left: 1px solid #ddd; border-right: 1px solid #888; }

.userTypes li { *display: inline !important; } /* IE7 only */

.userTypes .selected { background-color: #444 !important; color: white; text-shadow:none; border-right-color: #aaa; border-left: none; box-shadow:inset 1px 2px 6px #070707; }