Quick and Dirty WCF Service

Going to cover how to create and consume a WCF service.

Create

1. Create a new project, select "Web" project type and then choose "WCF Service Application".
2. Add a new WCF Service. This will add an interface and a .svc file with a code behind. 3. With the interface, define a method signature you want as your service.

using System.ServiceModel;

namespace MyService
{
    [ServiceContract]
    interface IWorkerService
    {
        [OperationContract]
        string DoWork(string workItem);
    }
}

This is called your "Contract".

4. Implement interface (contract) in the code behind of the .svc.

using System;

namespace MyService
{
    public class WorkerService : IWorkerService
    {
        public string DoWork(string workItem)
        {
            return string.Format("Work item: '{0}' received at: {1}", workItem, DateTime.Now);
        }
    }
}

That's it, your service is all set. Because you selected the web template, your service can be accessed via http by default.

Consume

1. Create a new Application, doesn't matter what kind.
2. Right-click on the References folder and select Add Service Reference...
3. In the Add Service Reference dialog, click the Discover button.
4. Your service should be discovered: 5. Accept the default Namespace and click OK.
6. Now you can instantiate and run this method:

ServiceReference1.WorkerServiceClient client = new ServiceReference1.WorkerServiceClient();
string result = client.DoWork("Some info.");

So you can see how this is much like creating a web service.

More Info: MSDN: Getting Started Tutorial (WCF)

XDocument - Selecting a multiple elements

Say we want to select all Person elements in this XML:

<Persons>
  <Person>
    <PersonId>1</PersonId>
    <PersonName>Mark</PersonName>
  </Person>
  <Person>
    <PersonId>2</PersonId>
    <PersonName>Matt</PersonName>
  </Person>
</Persons>

You can use the following code:

string returnValue = string.Empty;
XDocument ds = XDocument.Load("MyXml.xml");
var people = ds.Element("Persons").Elements("Person");

foreach (var singlePerson in people)
{
    returnValue += singlePerson.Element("PersonName").Value + "\r\n";
}

Console.WriteLine(returnValue);

The result will be:
Mark
Matt


More Info: MSDN: XContainer.Elements Method

XDocument - Selecting a single element value

XDocument is a new class that represents an XML document. It's a replacement to the XmlDocument and falls under the System.XML.LINQ namespace. When it comes time to selecting node values, you can say good-bye to XPath. Here is an example of selecting just one value from XML.

<Persons>
  <Person>
    <PersonId>1</PersonId>
    <PersonName>Mark</PersonName>
  </Person>
  <Person>
    <PersonId>2</PersonId>
    <PersonName>Matt</PersonName>
  </Person>
</Persons>

Say you want to select the first PersonName. You can write code like this:

XDocument ds = XDocument.Load("MyXml.xml");
string value = ds.Element("Persons").Element("Person").Element("PersonName").Value;

When you look for Element("Persons"), the XDocument is going to search for the FIRST match.

More Info: MSDN: XContainer.Element Method