RIATasks: A Simple Silverlight CRUD Example (using View Model)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Services;

namespace RIATasks.Web
{
    [WebService(Namespace = "http://OpenLightGroup.org/")]
    [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
    [System.ComponentModel.ToolboxItem(false)]
    public class WebService : System.Web.Services.WebService
    {
        #region GetCurrentUserID
        private int GetCurrentUserID()
        {
            int intUserID = -1;
            if (HttpContext.Current.User.Identity.IsAuthenticated)
            {
                // Get the current user
                intUserID = Convert.ToInt32(HttpContext.Current.User.Identity.Name);
            }
            return intUserID;
        }
        #endregion

        // Web Methods

        #region GetTasks
        [WebMethod]
        public List<Task> GetTasks()
        {
            // Create a collection to hold the results
            List<Task> colResult = new List<Task>();

            RIATasksDBDataContext DB = new RIATasksDBDataContext();

            var colTasks = from Tasks in DB.Tasks
                           where Tasks.UserID == GetCurrentUserID()
                           select Tasks;

            // Loop thru the Tasks
            foreach (var item in colTasks)
            {
                // Create a Task
                Task tmpTask = new Task();

                // Set only the TaskID and the Name
                // We do this because Description could be 
                // a large amount of data that will slow down
                // the application and we don't need it now
                tmpTask.TaskID = item.TaskID;
                tmpTask.TaskName = item.TaskName;

                // Add to the final results
                colResult.Add(tmpTask);
            }

            return colResult;
        }
        #endregion

        #region GetTask
        [WebMethod]
        public Task GetTask(int TaskID)
        {
            RIATasksDBDataContext DB = new RIATasksDBDataContext();

            var result = (from Tasks in DB.Tasks
                          where Tasks.TaskID == TaskID
                          where Tasks.UserID == GetCurrentUserID()
                          select Tasks).FirstOrDefault();

            return result;
        }
        #endregion

        #region DeleteTask
        [WebMethod]
        public string DeleteTask(int TaskID)
        {
            string strError = "";
            RIATasksDBDataContext DB = new RIATasksDBDataContext();

            try
            {
                var result = (from Tasks in DB.Tasks
                              where Tasks.TaskID == TaskID
                              where Tasks.UserID == GetCurrentUserID()
                              select Tasks).FirstOrDefault();

                if (result != null)
                {
                    DB.Tasks.DeleteOnSubmit(result);
                    DB.SubmitChanges();
                }
            }
            catch (Exception ex)
            {
                strError = ex.Message;
            }

            return strError;
        }
        #endregion

        #region UpdateTask
        [WebMethod]
        public string UpdateTask(Task objTask)
        {
            string strError = "";
            RIATasksDBDataContext DB = new RIATasksDBDataContext();

            try
            {
                var result = (from Tasks in DB.Tasks
                              where Tasks.TaskID == objTask.TaskID
                              where Tasks.UserID == GetCurrentUserID()
                              select Tasks).FirstOrDefault();

                if (result != null)
                {
                    result.TaskDescription = objTask.TaskDescription;
                    result.TaskName = objTask.TaskName;

                    DB.SubmitChanges();
                }
            }
            catch (Exception ex)
            {
                strError = ex.Message;
            }

            return strError;
        }
        #endregion

        #region InsertTask
        [WebMethod]
        public Task InsertTask(Task objTask)
        {
            RIATasksDBDataContext DB = new RIATasksDBDataContext();

            try
            {
                Task InsertTask = new Task();

                InsertTask.TaskDescription = objTask.TaskDescription;
                InsertTask.TaskName = objTask.TaskName;
                InsertTask.UserID = GetCurrentUserID();

                DB.Tasks.InsertOnSubmit(InsertTask);
                DB.SubmitChanges();

                // Set the TaskID 
                objTask.TaskID = InsertTask.TaskID;
            }
            catch (Exception ex)
            {
                // Log the error
                objTask.TaskID = -1;
                objTask.TaskDescription = ex.Message;
            }

            return objTask;
        }
        #endregion
    }
}