Binding and Behavior | WCF Tutorial pdf

Binding

Simple definition for Binding describes how the client will communicate with service. We can understand with an example.
Consider a scenario say, I am creating a service that has to be used by two type of client. One of the client will access SOAP using http and other client will access Binary using TCP. How it can be done? With Webser vice it is very difficult to achieve, but in WCF its just we need to add extra endpoint in the configuration file. 
<system.serviceModel>
   <services>
     <service name="MathService"
       behaviorConfiguration="MathServiceBehavior">
     <endpoint address="http://localhost:8090/MyService/MathService.svc" 
       contract="IMathService"
         binding="wsHttpBinding"/>
<endpoint address="net.tcp://localhost:8080/MyService/MathService.svc" 
contract="IMathService"
         binding="netTcpBinding"/> 
     </service>
   </services>
   <behaviors>
     <serviceBehaviors>
       <behavior name="MathServiceBehavior">
         <serviceMetadata httpGetEnabled="True"/>
         <serviceDebug includeExceptionDetailInFaults="true" />
       </behavior>
     </serviceBehaviors>
   </behaviors>
 </system.serviceModel>
See how simple it is in WCF. Microsoft is making everything simple.cording to its scope:
common behaviors affect all endpoints globally, service behaviors affect only service-related aspects, endpoint behaviors affect only endpoint-related properties, and operation-level behaviors affect particular operations.

Example:

In the below configuration information, I have mentioned the Behavior at Service level. In the service behavior I have mention the servieMetadata node with attribute httGetEnabled='true'.
This attribute will specifies the publication of the service metadata. Similarly we can add more behavior to the service.
<system.serviceModel>
   <services>
       <service name="MathService"
       behaviorConfiguration="MathServiceBehavior">
       <endpoint address="" contract="IMathService"
         binding="wsHttpBinding"/>
     </service>
   </services>
   <behaviors>
     <serviceBehaviors>
       <behavior name="MathServiceBehavior">
         <serviceMetadata httpGetEnabled="True"/>
         <serviceDebug includeExceptionDetailInFaults="true" />
       </behavior>
     </serviceBehaviors>
   </behaviors>
 </system.serviceModel>   
Note: 
Application can be controlled either through coding, configuring or through combination of both.
Specification mention in the configuration can also be overwritten in code.

Contracts

In WCF, all services are exposed as contracts. Contract is a platform-neutral and standard way of describing what the service does. Mainly there are four types of contracts available in WCF
Service Contract Service contracts describe the operation that service can provide. For Eg, a Service provide to know the temperature of the city based on the zip code, this service is called as Service contract.
It will be created using Service and Operational Contract attribute.
To know more on Service contract see Service contract tutorial.

Data Contract

Data contract describes the custom data type which is exposed to the client. This defines the data types, that are passed to and from service. Data types like int, string are identified by the client because it is already mention in XML schema definition language document, but custom created class or data types cannot be identified by the client e.g. Employee data type. By using DataContract we can make client to be aware of Employee data type that are returning or passing parameter to the method.
To know more on DataContract see DataContract tutorial.

Message Contract

 Default SOAP message for mat is provided by the WCF runtime for communication between Client and service. If it is not meeting your requirements then we can create our own message format. This can be achieved by using Message Contract attribute.
To know more on Message Contract see Message contract tutorial.

Fault Contract

Suppose the service I consumed is not working in the client application. I want to know the real cause of the problem. How I can know the error? For this we are having Fault Contract. Fault Contract provides documented view for error occurred in the service to client. This helps us to easy identity, what error has occurred.