Add update and delete list items programmatically in sharepoint-client object model

Add update and delete list items programmatically in sharepoint-client object model:

Insert the following namespace

using Microsoft.SharePoint;
using Microsoft.SharePoint.Client;

Use the following code.

   ClientContext ccsite;
   List listobj;
   ListItemCollection _icoll; 
   public MainPage()
        {
           InitializeComponent();

           ccsite = new ClientContext(ApplicationContext.Current.Url);
           ccsite.Load(ccsite.Web);
           listobj = ccsite.Web.Lists.GetByTitle("ListName");
           ccsite.Load(listobj);
        
            CamlQuery qry = new CamlQuery();
            qry.ViewXml = "<View/>";

            _icoll = listobj.GetItems(qry);
            ccsite.Load(_icoll);         
            ccsite.ExecuteQueryAsync(new ClientRequestSucceededEventHandler(success), null);
        }

  private void success(object sender,ClientRequestSucceededEventArgs arg)
   {
         Dispatcher.BeginInvoke(datacon);
   }

  private void datacon()
        {
            //For insert new data
            ListItem litem = listobj.AddItem(new ListItemCreationInformation());
            litem["ColumnName1"] = "One";
            litem["ColumnName2"] = "Two";
            litem.Update();
            ccsite.ExecuteQueryAsync(new ClientRequestSucceededEventHandler(succed), null);

            //For Update list data
            foreach (ListItem item in _icoll)
            {
                if (Convert.ToString(item["Likes"]) == "88")
                {
                    int id = Convert.ToInt16(item["ID"]);
                    ListItem litem = listobj.GetItemById(id);
                    litem["ColumnName1"] = "Yourdata";
                    litem.Update();
                    ccsite.ExecuteQueryAsync(new ClientRequestSucceededEventHandler(succed), null);
                }
            }

            //For Delete List item
            foreach (ListItem item in _icoll)
            {
                if (Convert.ToString(item["ColumnName1"]) == "YourData")
                {
                    int id = Convert.ToInt16(item["ID"]);
                    ListItem litem = listobj.GetItemById(id);
                    litem.DeleteObject();
                    ccsite.ExecuteQueryAsync(new ClientRequestSucceededEventHandler(succed), null);
                }
            }

              
        }

        private void succed(object sender, ClientRequestSucceededEventArgs arg)
        { }