Introduction to Client side programming in SharePoint 2010

SharePoint 2010 provides 3 new client-side object models: Managed, Silverlight and JavaScript. It provides libraries for each and they are located in the below locations.

Managed Object Model	Microsoft.SharePoint.Client.dll Microsoft.SharePoint.ClientRuntime.dll	ISAPI folder
Silverlight client object model	Microsoft.SharePoint.Client.Silverlight.dll Microsoft.SharePoint.Client.Silverlight.Runtime.dll	LAYOUTS\ClientBin folder
JavaScript client object model	SP.js	LAYOUTS folder

Each client object model interacts with SharePoint through a Windows Communication Foundation (WCF)

service named Client.svc, which is located in the ISAPI directory. Every request sent as a single Extensible Markup Language (XML) request to the Client.svc service. The results of the server-side calls are then sent back to the calling client in the form of a JavaScript Object Notation (JSON) object.

Server object model	Managed Model	Silverlight Model	Javascript Model
SPContext	ClientContext	ClientContext	ClientContext
SPSite	Site	Site	Site
SPWeb	Web	Web	Web
SPList	List	List	List
SPListItem	ListItem	ListItem	ListItem
SPField	Field	Field	Field

Here is a code sample:

//Server Object Model

SPSite siteCollection = SPContext.Current.Site;

string siteCollectionURL= siteCollection.Url;

//Managed Client Object Model

using (ClientContext clientContext = new ClientContext("Site URL"))

{

Site siteCollection = clientContext.Site;

clientContext.Load(siteCollection);

clientContext.ExecuteQuery();

string siteCollectionURL = siteCollection.Url;

}

//Silverlight Client Object Model

using (ClientContext clientContext = new ClientContext("Site URL"))

{

Site siteCollection = clientContext.Site;

clientContext.Load(siteCollection);

clientContext.ExecuteQuery();

string siteCollectionURL = siteCollection.Url;

}

//JavaScript Client Object Model

var siteCollection;

function getSiteCollection

{

var clientContext = new SP.ClientContext("/");

siteCollection = clientContext.get_site;

clientContext.load(site);

clientContext.executeQueryAsync(success, failure);

}

function success {

string siteCollectionURL = siteCollection.get_url;

}

function failure {

alert("Failure!");

}


Also you can check SharePoint object model articles.