How to get Item from ListItem with Client Object model

Question

I'm trying to printOut some items from a ListItem. But when run the code I get following exception:

"Invalid usage of query execution. The query should be executed by using ExecuteQuery method on the client context object".

This is the code Block:

  static void Main(string[] args)
    {
        try
        {
            ClientContext _clientContext = new ClientContext("http://spweb.reply.eu/sites/RC1/1003/");
        _clientContext.Credentials = new NetworkCredential("mossuser","Reply.96","replynet");
        SP.List list = _clientContext.Web.Lists.GetByTitle("Contenuti");
        CamlQuery query = new SP.CamlQuery();
        query.ViewXml = "@<View><Query><Where><Eq><FieldRef Name='tt_network_id' /><Value Type='Text'>clu_noe</Value></Eq></Where></Query></View>"; 
        var itemts= list.GetItems(query);
        _clientContext.Load(itemts);
        _clientContext.ExecuteQuery();
            Console.Write(itemts.Count().ToString());
        }
        catch (Exception e)
        {

            Console.Write(e.Message);
        }


        }

Answer 1

I guess you're missing call to clientContext.Load(List) in your code, try this

try
    {
        ClientContext _clientContext = new ClientContext("http://spweb.reply.eu/sites/RC1/1003/");
    _clientContext.Credentials = new NetworkCredential("mossuser","Reply.96","replynet");
    SP.List list = _clientContext.Web.Lists.GetByTitle("Contenuti");
    CamlQuery query = new SP.CamlQuery();
    query.ViewXml = "@<View><Query><Where><Eq><FieldRef Name='tt_network_id' /><Value Type='Text'>clu_noe</Value></Eq></Where></Query></View>"; 
    var itemts= list.GetItems(query);
    _clientContext.Load(list);
    _clientContext.Load(itemts);
    _clientContext.ExecuteQuery();
        Console.Write(itemts.Count().ToString());
    }
    catch (Exception e)
    {

        Console.Write(e.Message);
    }

Find out more here http://msdn.microsoft.com/en-us/library/ee857094.aspx#SP2010ClientOM_Object_Identity

Answer 2

Remove the () after itemts.Count

static void Main(string[] args) 
{ 
    try 
    { 
      ClientContext _clientContext = new ClientContext("http://spweb.reply.eu/sites/RC1/1003/"); 
      _clientContext.Credentials = new NetworkCredential("mossuser","Reply.96","replynet"); 
      SP.List list = _clientContext.Web.Lists.GetByTitle("Contenuti"); 
      CamlQuery query = new SP.CamlQuery(); 
      query.ViewXml = "@<View><Query><Where><Eq><FieldRef Name='tt_network_id' /><Value Type='Text'>clu_noe</Value></Eq></Where></Query></View>";  
      var itemts= list.GetItems(query); 
      _clientContext.Load(itemts); 
      _clientContext.ExecuteQuery(); 
      Console.Write(itemts.Count.ToString()); 
    } 
    catch (Exception e) 
    { 
      Console.Write(e.Message); 
    } 
} 

Answer 3

static void Main(string[] args)
    {
        try
        {
            ClientContext _clientContext = new ClientContext("http://spweb.reply.eu/sites/RC1/1003/");
        _clientContext.Credentials = new NetworkCredential("mossuser","Reply.96","replynet");
        SP.List list = _clientContext.Web.Lists.GetByTitle("Contenuti");
        _clientContext.Load(list);
        _clientContext.ExecuteQuery();
        CamlQuery query = new SP.CamlQuery();
        query.ViewXml = "@<View><Query><Where><Eq><FieldRef Name='tt_network_id' /><Value Type='Text'>clu_noe</Value></Eq></Where></Query></View>"; 
        var itemts= list.GetItems(query);
        _clientContext.Load(itemts);
        _clientContext.ExecuteQuery();
            Console.Write(itemts.Count().ToString());
        }
        catch (Exception e)
        {

            Console.Write(e.Message);
        }


        }

You have to load each item before doing any operation on them. thus only you can get it be executed. You forget to load _clientContext.Load(list); _clientContext.ExecuteQuery();
Thank you..