Creating and Consuming Your First WCF Service

Introduction

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

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[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.

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[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:

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 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:

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<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" andcontract="WcfSample.IStock".

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

Creating a Client to Consume Service

To create a client, I will create a web application. Please follow these steps.

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:
4. 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:
   
   
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   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); 
   Label1.Text = sb.ToString(); 

5. Here are a few screenshots from our final application: