using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.SharePoint;
using Microsoft.SharePoint.Client;
namespace ClientObjectModel
{
class Program
{
static void Main(string[] args)
{

//Add user custom action to Site Actions menu using Client Object Model

string siteURL = "http://serverName:1111/sites/SPSiteDataQuery/";
ClientContext context = new ClientContext(siteURL);

UserCustomActionCollection collUserCustomAction =context.Web.UserCustomActions;
UserCustomAction userCustomAction = collUserCustomAction.Add();
userCustomAction.Location = "Microsoft.SharePoint.StandardMenu";
userCustomAction.Sequence = 100;
userCustomAction.Group = "SiteActions";
userCustomAction.Title = "Custom Site Action";
userCustomAction.Url = "/_layouts/settings.aspx";
userCustomAction.Update();
context.Load(userCustomAction);
context.ExecuteQuery();
}
}
}