Update List Items Client Object Model

“Client” in the namespace.  For example, in the server object model you have:
·         Microsoft.SharePoint.SPSite
·         Microsoft.SharePoint.SPWeb
·         Microsoft.SharePoint.SPList
In the client object model you have:
·         Microsoft.SharePoint.Client.Site
·         Microsoft.SharePoint.Client.Web
     ·         Microsoft.SharePoint.Client.List

NameSpace:


Microsoft.SharePoint.Client.dll
Microsoft.SharePoint.Client.Runtime.dll


Example Code:

ClientContext context = new ClientContext("http://peakfinders.com");
List list = context.Web.Lists.GetByTitle("yourlistname");
CamlQuery query = new CamlQuery();
query.ViewXml = "<View/>";
ListItemCollection items = list.GetItems(query);

context.Load(items);

context.ExecuteQuery();

foreach(ListItem item in items)
    if ((item.Id % 2) == 0)
    {
        item["Title"] += "**";
        item.Update();
    }

context.ExecuteQuery();