SharePoint 2010 Working with Dates in CAML

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using Microsoft.SharePoint.Client;

namespace ClientObjectModelAndDate
{
    public partial class DemoForm : System.Windows.Forms.Form
    {
        public DemoForm()
        {
            InitializeComponent();
        }

        private string ListTitle = "Client Object Model - CAML Tasks";

        private void CreateDataButton_Click(object sender, EventArgs e)
        {
            // Open context
            ClientContext clientContext = new ClientContext(UrlText.Text);
            List list = clientContext.Web.Lists.GetByTitle(ListTitle);
            clientContext.Load(list);

            try
            {
                // Try get task list
                clientContext.ExecuteQuery();
            }
            catch (ServerException)
            {
                // Create task list
                ListCreationInformation listCreationInformation = new ListCreationInformation();
                listCreationInformation.Title = ListTitle;
                listCreationInformation.TemplateType = (int)ListTemplateType.Tasks;

                list = clientContext.Web.Lists.Add(listCreationInformation);

                clientContext.ExecuteQuery();
            }

            // insert data
            DateTime date = DateTime.Today.AddMonths(2);
            for (int i = 1; i <= 5; i++)
            {
                for (int j = 1; j <= 3; j++)
                {
                    ListItemCreationInformation info = new ListItemCreationInformation();
                    ListItem item = list.AddItem(info);
                    item["Title"] = "A task item";
                    item["DueDate"] = date;

                    item.Update();

                    clientContext.ExecuteQuery();
                }

                date = date.AddMonths(-1); // Decrement Month on each outer loop
            }
        }

        private void ShowAllDataButton_Click(object sender, EventArgs e)
        {
            // Load Data
            ClientContext context = new ClientContext(UrlText.Text);
            List list = context.Web.Lists.GetByTitle(ListTitle);
            CamlQuery query = new CamlQuery();
            query.ViewXml = "<View/>";
            ListItemCollection items = list.GetItems(query);

            context.Load(list);
            context.Load(items);

            context.ExecuteQuery();

            // Show Data
            DataTable table = new DataTable();
            table.Columns.Add("Id");
            table.Columns.Add("Title");
            table.Columns.Add("DueDate");

            foreach (ListItem item in items)
                table.Rows.Add(item.Id, item["Title"], item["DueDate"]);

            grid1.DataSource = table;
        }

        private void ShowThisMonthDataButton_Click(object sender, EventArgs e)
        {
            // Prepare start and end dates
            DateTime startDate = new DateTime(DateTime.Today.Year, DateTime.Today.Month, 1);
            DateTime endDate = startDate.AddMonths(1).AddMinutes(-1);

            // Format dates
            string startDateFx = startDate.ToString("yyyy-MM-ddTHH:mm:ssZ");
            string endDatFx = endDate.ToString("yyyy-MM-ddTHH:mm:ssZ");

            // Load Data for this Month
            ClientContext clientContext = new ClientContext(UrlText.Text);
            List list = clientContext.Web.Lists.GetByTitle(ListTitle);
            CamlQuery query = new CamlQuery();
            query.ViewXml = @"<View>" +
            "<Query>" +
                "<Where>" +
                    "<And>" +
                        "<Geq>" +
                            "<FieldRef Name='DueDate'/>" +
                            "<Value Type='DateTime' IncludeTimeValue='FALSE'>" + startDateFx + "</Value>" +
                        "</Geq>" +
                        "<Leq>" +
                            "<FieldRef Name='DueDate'/>" +
                            "<Value Type='DateTime' IncludeTimeValue='FALSE'>" + endDatFx + "</Value>" +
                        "</Leq>" +
                    "</And>" +
                "</Where>" +
            "</Query>" +
            "</View>";
            ListItemCollection listItems = list.GetItems(query);
            clientContext.Load(listItems, items => items.Include(
                                                            item => item["Id"],
                                                            item => item["Title"],
                                                            item => item["DueDate"]
                                                            ));
            clientContext.ExecuteQuery();

            // Show Data
            DataTable table = new DataTable();
            table.Columns.Add("Id");
            table.Columns.Add("Title");
            table.Columns.Add("DueDate");

            foreach (ListItem item in listItems)
                table.Rows.Add(item.Id, item["Title"], item["DueDate"]);

            grid2.DataSource = table;
        }
    }
}