Saturday, February 28, 2015

How to create instance of generic class using reflection

In this post I am going to show how to create instance of generic class using c# reflection.The trick is to use the MakeGenericType to make the argument(s) and then call create Instance. Here is a code snippet:

Type d1 = typeof(List<>);
 
Type[] typeArgs = { typeof(string) };
 
Type makeme = d1.MakeGenericType(typeArgs);
 
object o = Activator.CreateInstance(makeme);
 
List<string> itsMe = o as List<string>;

Thursday, February 26, 2015

How to host wcf service in IIS using Tcp protocol

In this post I am going to show you how to host WCF service in IIS using TCP protocol.By default, the TCP WCF activation service is not enabled on your machine. You can follow these steps to enable the TCP activation for WCF services:
  1. Go to Control Panel | Programs | Turn Windows features on or off.
  2. Expand the Microsoft .Net Framework 3.5.1 node on Windows 7
  3. Check the checkbox for Windows Communication Foundation Non-HTTP Activation on Windows 7
getfile
Next,Create the IIS application to host the WCF application using TCP protocol.Follow these steps
  1. Open run command and type inetmgr
  2. Create a new application and point to physical folder.
  3. Select the DefaultAppPoll  and make sure your default app pool is a .NET 4.0.X application pool.
  4. Right-click on web application, select Manage Application | Advanced Settings, and then add net.tcp to Enabled Protocols.(Make sure you use all lowercase letters and separate it from the existing HTTP protocol with a comma)
image
Now the service is hosted in IIS using the TCP protocol.

Tuesday, February 24, 2015

Todo App using Web API and Knockout

In this post I am going to show you how to develop a todo app using knockoutjs and microsoft Web API.

What is knockoutjs

”Knockout is a standalone JavaScript implementation of the Model-View-ViewModel pattern with templates. The underlying principles are therefore: a clear separation between domain data, view components and data to be displayed.”-Wikipedia

Knockout is built around three core features:

  1. Observables and dependency tracking
  2. Declarative bindings
  3. Templating

Before diving to example code first go through the following http://knockoutjs.com/documentation/observables.html#mvvm_and_view_models

Open visual studio and create a new Web API application

image

Open Package Manager console and install knockoutjs as shown in below image

image

Right click the Model folder and add a new class named TodoItem and paste following code.

 public class TodoItem
    {
        public int Id { get; set; }
        public string Title { get; set; }
        public bool Done { get; set; }
    }

Right click the model folder again and add a new Interface class and paste following code

 public interface ITodoRepository
    {
        IEnumerable<TodoItem> GetAll();
        void AddTodo(TodoItem item);
    }
}

Add a new class inside model folder and paste following code inside it

 public class TodRepository : ITodoRepository
    {
        private static List<TodoItem> _localTodos;
        private int MaxId()
        {
            return _localTodos.Max(x => x.Id) + 1;
        }
        public TodRepository()
        {
            _localTodos = new List<TodoItem>() {
                    new TodoItem{Id=1,Title="Todo Item 1",Done=false},
                    new TodoItem{Id=2,Title="Todo Item 2",Done=false},
                    new TodoItem{Id=3,Title="Todo Item 3",Done=true},
                };

        }


        public IEnumerable<TodoItem> GetAll()
        {
            return _localTodos;
        }

        public void AddTodo(TodoItem item)
        {
           
            var id = MaxId();
            TodoItem newTodo = new TodoItem() { Id = id, Title = item.Title, Done = item.Done };
            _localTodos.Add(newTodo);
        }

        public void Delete(int id)
        {
            var taskToDeleted = _localTodos.Find(x => x.Id == id);
            _localTodos.Remove(taskToDeleted);
        }

    }

Go to controller folder and rename the ValuesController to TodoController and paste the following code.

 public class TodoController : ApiController
    {
        // GET api/values
        private ITodoRepository _repo;
        public TodoController()
        {
            _repo = new TodRepository();
        }
        public IEnumerable<TodoItem> Get()
        {
            return _repo.GetAll();
        }

        public void Post([FromBody]TodoItem value)
        {
            _repo.AddTodo(value);
        }

    }

Till now I have not done nothing related to knockoutjs.Let’s start the second part

Opend Index.cshtml and remove everything from it and paste following markup

<h1>Todo App</h1>
<div class="row">

    <form role="form">
        <div class="form-group">
            <label for="email">Title:</label>
            <input type="text" class="form-control" data-bind="value: taskName" id=" txttitle" placeholder="Enter Title">
        </div>

        <button type="submit" data-bind="click:addTask" class="btn btn-default">Submit</button>
    </form>
    <hr />
    <div class="col-md-6">
        <table class="table">
            <thead>
                <tr>
                    <th>Title</th>
                    <th>Completed?</th>
                </tr>
            </thead>
            <tbody data-bind="foreach:todos">
                <tr>
                    <td data-bind="text:Title"></td>
                    <td><input type="checkbox" data-bind="checked:Done" /> </td>
                    <td>
                        <a href="#" title="Delete the task" data-bind="click:$parent.deleteTodo" class="glyphicon glyphicon-trash"></a>
                    </td>


                </tr>
            </tbody>
        </table>
    </div>
</div>


 

The basic layout of the html is simple, and taken from the inspiring example applications. The noteworthy parts are the data-bind attributes that are sprinkled in the appropriate places:

There is a input textbox which has the same value as the viewModels taskName and there is button which will fire addTask function on viewmodel.

Right click the project and add new javascript file inside scripts folder named todoApp.js and add following code

function TodoItem(Id, Title, Done) {
    var self = this;
    self.Id = Id;
    self.Title = ko.observable(Title);
    self.Done = ko.observable(Done);
    self.Done.subscribe(function () {


    });
}
function TodoViewModel() {

    var self = this;
    self.todos = ko.observableArray([]);
    self.taskName = ko.observable();

    self.addTask = function () {
        var todoItem = new TodoItem(0, self.taskName(), false);
        self.todos.push(todoItem);
        $.ajax({
            type: "POST",
            url: "/api/todo",
            data: ko.toJSON(todoItem),
            dataType: "json",
            contentType: "application/json",
            success: function (data) {

            }

        });

    };
    self.deleteTodo = function (data) {
        self.todos.remove(data);
        $.ajax({
            type: "DELETE",
            url: "/api/todo/" + data.Id,
            dataType: "json",
            contentType: "application/json",
            success: function () {
               
            }

        });
    };
    self.init = function () {
        $.getJSON("/api/todo", function (data) {
            $.each(data, function (index, item) {
                self.todos.push(new TodoItem(item.Id, item.Title, item.Done));
            });
        });
    };

}
$(document).ready(function () {

    var viewModel = new TodoViewModel();
    viewModel.init();
    ko.applyBindings(viewModel);
});

open _Layout.cshtml and add following script

    <script src="~/Scripts/knockout-3.2.0.js"></script>
    <script src="~/Scripts/todoApp.js"></script>

Monday, February 23, 2015

How to enable CORS in web API2

In this post I am going to show you a very simple and useful tips that how to enable CORS in web API2.
What is CORS
Cross-origin resource sharing (CORS) is a mechanism that allows many resources (e.g. fonts, JavaScript, etc.) on a web page to be requested from anotherdomain outside the domain from which the resource originated
How to enable in CORS in web API2
In Visual Studio, from the Tools menu, select Library Package Manager, then select Package Manager Console. In the Package Manager Console window, type the following command:
Install-Package Microsoft.AspNet.WebApi.Cors
Open the file App_Start/WebApiConfig.cs. Add the following code to the WebApiConfig.Register method.
 public static void Register(HttpConfiguration config)
        {
            // New code
            config.EnableCors();

            config.Routes.MapHttpRoute(
                name: "DefaultApi",
                routeTemplate: "api/{controller}/{id}",
                defaults: new { id = RouteParameter.Optional }
            );
        }

Sunday, February 22, 2015

How to convert DataSet to List

In this post I am going to show you a very useful c# code snippet that convert DataSet to List<T>.

 

   public static List<T> ToCollection<T>(this DataTable dt)
        {
            List<T> lst = new List<T>();
            Type tClass = typeof(T);
            PropertyInfo[] pClass = tClass.GetProperties();
            List<DataColumn> dc = dt.Columns.Cast<DataColumn>().ToList();
            T cn;
            foreach (DataRow item in dt.Rows)
            {
                cn = (T)Activator.CreateInstance(tClass);
                foreach (PropertyInfo pc in pClass)
                {
                  
                   DataColumn d = dc.Find(c => c.ColumnName == pc.Name);
                   if (d != null)
                   {
                       if (item[pc.Name] != DBNull.Value)
                       {
                           pc.SetValue(cn, (item[pc.Name]), null);
                       }
                   }   
                }
                lst.Add(cn);
            }
            return lst;
        }

Tuesday, February 17, 2015

Self host web API

In this post I will show you how to create web api that run outside IIS application.
Open visual studio and create a console application
image

Add the Web API and OWIN Packages

From the Tools menu, click Library Package Manager, then click Package Manager Console. In the Package Manager Console window, enter the following command:
Install-Package Microsoft.AspNet.WebApi.OwinSelfHost
image
Right click  the project and add new class named Startup.cs and add following code snippet in it
public class Startup 
    { 
        // This code configures Web API. The Startup class is specified as a type
        // parameter in the WebApp.Start method.
        public void Configuration(IAppBuilder appBuilder) 
        { 
            // Configure Web API for self-host. 
            HttpConfiguration config = new HttpConfiguration(); 
            config.Routes.MapHttpRoute( 
                name: "DefaultApi", 
                routeTemplate: "api/{controller}/{id}", 
                defaults: new { id = RouteParameter.Optional } 
            ); 

            appBuilder.UseWebApi(config); 
        } 
    } 

Next, add a Web API controller class. In Solution Explorer, right click the project and select Add / Class to add a new class named HelloController and add following code snippet
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Web.Http;

namespace SelfHostWebApi
{
    public class HelloController : ApiController
    {
        // GET api/values/5 
        public string Get(int id)
        {
            return "Hello API";
        }
    }
}
Open Program.cs and add following code inside main method
using Microsoft.Owin.Hosting;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Net.Http;
using System.Text;
using System.Threading.Tasks;

namespace SelfHostWebApi
{
    class Program
    {
        static void Main(string[] args)
        {
            string baseAddress = "http://localhost:9000/";

            // Start OWIN host 
            using (WebApp.Start<Startup>(url: baseAddress))
            {
                // Create HttpCient and make a request to api/values 
                HttpClient client = new HttpClient();

                var response = client.GetAsync(baseAddress + "api/hello").Result;

                Console.WriteLine(response);
                Console.WriteLine(response.Content.ReadAsStringAsync().Result);
            }

            Console.ReadLine();
        }
    }
}

Your self hosted web api is ready.When you run the application you will see following output if everything works fine
image


How to create Fibonacci series using Linq

In this post I am going to show you how to generate fiboancci number series using Linq.

What is Fibonacci series : The Fibonacci Sequence is the series of numbers: 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, ... The next number is found by adding up the two numbers before it.

 public static IEnumerable<int> Fib(int n)
        {
            List<int> fibs = new List<int>();
            Enumerable.Range(0, n)
                .ToList()
                .ForEach(f => fibs.Add((f <= 1 ? 1 : fibs[f - 2] + fibs[f - 1])));
            return fibs;


        }

How to create chat application using microsoft asp.net signalr


open visual studio and create a new MVC application image
Select Empty MVC application
image
Open Package Manager Console and install SignalR
image
Right click on project and add new class ChatHub and inherit from Hub class that resides in Microsoft.AspNet.SignalR
image
public class ChatHub:Hub
    {
       //this method is called when client send message
        public void sendMessage(string message)
        {
           //this method brodcast message to all connected client
            Clients.All.newMessage(message);
        }
    }
Right click on project and add new class named Startup and add following code inside it
 public class Startup
    {
        public void Configuration(IAppBuilder app)
        {
            app.MapSignalR();
        }
    }
Create a new html page and add following markup inside it.You can see that I have added three JavaScript lib :jquery,jqery-signalr* and  signalr/hubs.Signalr/hubs contains functions for interacting with server side hub class and also it generated automatically by signalr framework
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
    <title></title>
    <script src="Scripts/jquery-1.6.4.min.js"></script>
    <script src="Scripts/jquery.signalR-2.2.0.js"></script>
    <script src="signalr/hubs"></script>
    <script>
        $(document).ready(function () {
            var chatHub = $.connection.chatHub;
            chatHub.client.newMessage = function (data) {
                $("#messages").append("<li>" + data + "</li>");
            };
            chatHub.connection.start().done(function () {
                $("#btnSend").click(function () {
                    chatHub.server.sendMessage($("#txtMessage").val());
                });

            });

        });
    </script>
</head>
<body>
    <label for="txtMessage">Message</label>
    <input type="text" name="txtMessage" id="txtMessage" />
    <input type="button" value="send" id="btnSend" />
    <hr />
    <ul id="messages"></ul>
</body>
</html>

Access to the Hubs from outside of the Hub class

The Clients dynamic property of the Hub gives you access to all clients connected to the hub within the hub class. However, what if you would like to push data to the clients from outside of the Hub class.Use following code snippet and replace HubClass with your own class and get access of the signalr clients and server dynamic properties/methods.

var myHub = GlobalHost.ConnectionManager.GetHubContext<HubClass>();

Compare Linq and Ruby Part1

Linq Where equivalent in Ruby

One of the most used (just guessing) LINQ methods would be Where(), in .NET allows you to provide a Lambda that is used to filter a collection of objects

 var ints = new[] {
 	13, 42, 96, 2, 83
 };
 var evens = ints.Where(x = > x % 2 == 0);
 foreach(int i in evens) {
 	Console.WriteLine(i);
 }

And in Ruby this functionality would be achieved with select.

ints = [13, 42, 96, 2, 83]
evens = ints.select { | x | x % 2 == 0 }
puts evens

Linq OrderBy expression equivalent in Ruby

To sort a sets of elements in c# with Linq we use OrderBy

var words = new[] {
	"Perl", "c#", "ruby", "java"
};
var ordered = words.OrderBy(x = > x);
ordered.ToList().ForEach(Console.WriteLine);

And in Ruby this functionality would be achieved with sort.

 words = ["Perl", "c#", "ruby", "java"] 
 ordered = words.sort 
 puts ordered

Linq Select expression equivalent in Ruby

In .NET to convert a set of items to another set one would use the Select() method. This method is also useful for creating projections of a collection

 var words = new[] {
 	"Hello", "Word"
 };
 var shouting = words.Select(x = > x.ToUpper();

and the ruby equivalent is map

words = % w {
	Hello World
}
shouting = words.map { | x | x.upcase
}
puts shouting

Saturday, February 7, 2015

How to post data using HttpClient

In this post I will show you how to post data to web api using HttpClient.

  private static async Task PostJSON()
        {
            HttpClient httpClient = new HttpClient();
            HttpContent content = new StringContent(@"{ ""Username"": """ + "etc." + @"""}");
            content.Headers.ContentType = new MediaTypeHeaderValue("application/json");
            HttpResponseMessage response =
                await httpClient.PostAsync("http://myapi.com/authentication", content);
            string statusCode = response.StatusCode.ToString();
        }

        /// <summary>
        /// Post Key/Value
        /// </summary>
        /// <returns></returns>
        private static async Task Post()
        {
            HttpClient client = new HttpClient();

            var values = new Dictionary<string, string>();
            values.Add("author", "santosh");
            values.Add("text", "singh");
            var content = new FormUrlEncodedContent(values);
            var response = await client.PostAsync("http://localhost:4500/quote", content);
        }