Month: May 2012

ModelState Errors in MVC through JSON

On May 15, 2012

Normally, when you used HttpPost/Form submission to post the view through the controller then you can have the model validation applied automatically through @Html.ValidationSummary()

But how do you get the ModelState errors through Json? You can still use LINQ to get the model errors from the ModelState and pass it through JSON

Code Snippet

public ActionResult JsonRegister(MemberModel.RegistrationModel model)
        {
            string error = string.Empty;
            if (!ModelState.IsValid)
            {
                IEnumerable<System.Web.Mvc.ModelError> modelerrors = ModelState.SelectMany(x => x.Value.Errors);
                foreach (var modelerror in modelerrors)
                {
                    error += modelerror.ErrorMessage + “\n”;
                }
            }
            return Json(new { success = false, errors = error }, JsonRequestBehavior.AllowGet);
        }

SlideRocket – Cloud

By fransiscuss

On May 14, 2012

In Uncategorized

This is the cloud version of Microsoft Power Point. It is created by the company that I’m working for at the moment. I’m blogging this not because I’m working for them but I’m blogging this based on my personal opinion

It is a powerful web application and It really works as it allows you to use Slide Rocket to share and collaborate your presentation slides with everyone and you don’t need to carry your power point slides file or your laptop. It supports mobile device as well such as an iPad. You just need a connection to the internet

For the standard functionality (Create a presentation slides), it is FREE for life but when you want to use versioning for your presentation, or when you want to have more security control over your presentation, or even to analyse who has accessed your slide and when was it then you need to have monthly subscription. Check it out guys

http://www.sliderocket.com

ps: some guy is using this web application for their resume! and it’s impressive!

http://www.sliderocket.com/blog/2012/05/creative-resume-idea/?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+SliderocketMissionControl+%28SlideRocket+Mission+Control%29

Dependency Injection using Simple Injector Tutorial

By fransiscuss

On May 14, 2012

In .NET

This is a simple tutorial in how to use Dependency Injection using SimpleInjector (You can get this package from NuGet)

In this case, I use SimpleInjector to manage my Data Context – I want my Data Context to be per request (Unit of Work per request). The concept of this dependency Injection is to have a global container where you can resolve your object from

1. Create an extension method to the Simple Injector

Code Snippet

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using SimpleInjector;
using System.Diagnostics;
using System.Linq.Expressions;
///<summary>
/// Extension methods for registering types on a per web request basis.
///</summary>
public static partial class SimpleInjectorPerWebRequestExtensions
{
    [DebuggerStepThrough]
    public static void RegisterPerWebRequest<TService, TImplementation>(
        this Container container)
        where TService : class
        where TImplementation : class, TService
    {
        Func<TService> instanceCreator =
            () => container.GetInstance<TImplementation>();
        container.RegisterPerWebRequest<TService>(instanceCreator);
    }
    [DebuggerStepThrough]
    public static void RegisterPerWebRequest<TService>(
        this Container container,
        Func<TService> instanceCreator) where TService : class
    {
        var creator =
            new PerWebRequestInstanceCreator<TService>(instanceCreator);
        container.Register<TService>(creator.GetInstance);
    }
    [DebuggerStepThrough]
    public static void RegisterPerWebRequest<TConcrete>(this Container container)
        where TConcrete : class
    {
        container.Register<TConcrete>();
        container.ExpressionBuilt += (sender, e) =>
        {
            if (e.RegisteredServiceType == typeof(TConcrete))
            {
                var transientInstanceCreator = Expression.Lambda<Func<TConcrete>>(
                    e.Expression, new ParameterExpression[0]).Compile();
                var creator = new PerWebRequestInstanceCreator<TConcrete>(
                    transientInstanceCreator);
                e.Expression = Expression.Call(Expression.Constant(creator),
                    creator.GetType().GetMethod(“GetInstance”));
            }
        };
    }
    [DebuggerStepThrough]
    public static void DisposeInstance<TService>() where TService : class
    {
        object key = typeof(PerWebRequestInstanceCreator<TService>);
        var instance = HttpContext.Current.Items[key] as IDisposable;
        if (instance != null)
        {
            instance.Dispose();
        }
    }
    private sealed class PerWebRequestInstanceCreator<T> where T : class
    {
        private readonly Func<T> instanceCreator;
        internal PerWebRequestInstanceCreator(Func<T> instanceCreator)
        {
            this.instanceCreator = instanceCreator;
        }
        [DebuggerStepThrough]
        public T GetInstance()
        {
            var context = HttpContext.Current;
            if (context == null)
            {
                // No HttpContext: Let’s create a transient object.
                return this.instanceCreator();
            }
            object key = this.GetType();
            T instance = (T)context.Items[key];
            if (instance == null)
            {
                context.Items[key] = instance = this.instanceCreator();
            }
            return instance;
        }
    }
}

2. Modify Global.asax – The class name will be MvcApplication in MVC Project

Code Snippet

 #region “Dependency Injection”
        private static Container Container;
        public static T GetInstance<T>() where T : class
        {
            return Container.GetInstance<T>();
        }
        protected void RegisterDependency()
        {
            //Create a main containers
            var container = new Container();
            // 2. Configure the container (register)
            container.RegisterPerWebRequest<IUnitOfWork>(() => new UnitOfWork(new PosDataContext()));
            container.Register<ITableRepository, TableRepository>();
            container.Verify();
            Container = container;
        }
        #endregion
        protected void Application_Start()
        {
            AreaRegistration.RegisterAllAreas();
            RegisterGlobalFilters(GlobalFilters.Filters);
            RegisterRoutes(RouteTable.Routes);
            BundleTable.Bundles.RegisterTemplateBundles();
            RegisterDependency();
        }
        protected void Application_EndRequest(object src, EventArgs e)
        {
            ServiceStack.MiniProfiler.Profiler.Stop();
            SimpleInjectorPerWebRequestExtensions.DisposeInstance<IUnitOfWork>();
        }

3. Consume it from the controller – Call the container in the Global.asax to resolve the object (GetInstance function)

Code Snippet

public ActionResult Index()
        {
            ViewBag.Title = “Tables”;
            return View(MvcApplication.GetInstance<IUnitOfWork>().TableRepository.Get(e => e.Active));
        }

IoC Container Benchmarks

By fransiscuss

On May 13, 2012

In .NET

I found this benchmark for different IoC in .NET. Personally I’ve been using Unity, Ninject and SimpleInjector. I like SimpleInjector because it is very simple and surprisingly it is quite fast compared with the rest. Performance is just one of the aspect of IoC but it doesn’t always mean everything

http://www.palmmedia.de/Blog/2011/8/30/ioc-container-benchmark-performance-comparison

http://www.iocbattle.com/

Debugging Knockout

By fransiscuss

On May 10, 2012

In Javascript

I’ve been learning Knockout recently and I found that sometimes it is hard to find out how your View Model is being formed especially when you create the view from Model in MVC

To inspect your view model, you can use firebug console and run below command, this will give you a full navigated View Model and allow you to drill down

console.group(“Dumping view model”);
console.dir(ko.toJS(new JobResultViewModel()));
console.groupEnd();

alternatively you can also put this code in your template

Feel free to let me know if you have any other way to debug