Creating and Consuming Your First WCF Service

Introduction

In this article, I will examine how to create and consume a WCF service. WCF is a next-generation programming platform and runtime system for building, configuring and deploying service-oriented applications. For more details, please see here.

Creating a WCF Service

I will create a stock service to demonstrate a WCF service. To create a WCF service, please follow these steps:

1. Launch Visual Studio 2008.
2. Click on File -> new -> project, then select WCF service application.
3. It will create a WCF service application template.

I will delete the default contract and then create an IStock contract as shown below.

Using the Code

[ServiceContract]

    public interface IStock

    {

        [OperationContract]

        Stock GetStock(string Symbol);  

    }

The above contract has one method that returns a stock object for a given symbol. Here is our Stock class that has Symbol, Date, Company and Close properties respectively.

[DataContract]

    public class Stock

    {

        [DataMember]

        public string Symbol { get; set; }

        [DataMember]

        public DateTime Date { get; set; }

        [DataMember]

        public string Company { get; set; }

        [DataMember]

        public decimal Close { get; set; }

    }

Next, I will delete the default service and create a Stock service that will implement the Istock contract as shown below:

 public class Stocks : IStock

    {

        #region IStock Members

        public Stock GetStock(string Symbol)

        {

            Stock st = null;

            switch (Symbol.ToUpper())

            {

                case "GOOG":

                    st = new Stock { Symbol = Symbol, Date = DateTime.Now,

                          Company = "Google Inc.", Close = 495 };

                    break;

                case "MSFT":

                    st = new Stock { Symbol = Symbol, Date = DateTime.Now,

                          Company = "Microsoft Corporation", Close = 25 };

                    break;

                case "YHOO":

                    st = new Stock { Symbol = Symbol, Date = DateTime.Now,

                          Company = "Yahoo! Inc.", Close = 17 };

                    break;

                case "AMZN":

                    st = new Stock { Symbol = Symbol, Date = DateTime.Now,

                          Company = "Amazon.com, Inc.", Close = 92 };

                    break;

            }

            return st;

        }

        #endregion

    }

In the above service, I implemented IStock contract that has a GetStock method which returns stock object for a given Symbol.

Now, I will have the following endpoints in my web.config:

<service behaviorConfiguration="WcfSample.Service1Behavior" name="WcfSample.Stocks">

<endpoint address="" binding="wsHttpBinding" contract="WcfSample.IStock">

<identity>

 <dns value="localhost"/>

 </identity>

</endpoint>

<endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange"/>

</service>

In the above configuration, we have address="" which is localhost, binding="wsHttpBinding" and contract="WcfSample.IStock".

Now I will compile the service and build a client to consume the service.

Creating a Client to Consume Service

1. Right Click on Solution -> Add -> new project, then select ASP.NET web application.
2. It will create a web application template.
3. Now, I will add the service reference. To add a service reference, select client application, then add a service reference. Since our client is in a same solution, I will click discover and service in the solution as shown below:
   
   
   

In default.aspx, I will create a simple UI, a textbox to enter the stock symbol and a button to call the service to get stock information. Here is our code behind:
ServiceReference2.StockClient sc = new ServiceReference2.StockClient();
ServiceReference2.Stock st = sc.GetStock(TextBox1.Text.Trim());
StringBuilder sb = new StringBuilder();
sb.AppendFormat("<B>Company:</B> {0}<br />", st.Company);
sb.AppendFormat("<B>Date: </B>{0}<br />", st.Date);
sb.AppendFormat("<B>Close: </B>{0}<br />", st.Close);
sb.AppendFormat("<B>Symbol: </B>{0}<br />", st.Symbol);

12.Label1.Text = sb.ToString();

  
Here are a few screenshots from our final application:

Summary

In this article, we examined how to create and consume a WCF service. As you can see, creating and consuming WCF service with Visual studio 2008 is pretty simple.

http://www.aspnettutorials.com/tutorials/advanced/introduction-to-wcf-vb.aspx