Gaute's .net weblog - ASP.NET

Changing the ASP.NET MVC DefaultControllerFactory with a custom using StructureMap and Common Service Locator.

Gaute Magnussen — Fri, 12 Jun 2009 11:18:17 GMT

This blog post is about changing the DefaultControllerFactory to a custom one to allow constructor dependency injection. In this post I use Structuremap, CommonServiceLocator and I use a slightly changed version of the CommonServiceLocator.StructureMapAdatpter.

The DefaultControllerFactory needs a constructor without any input parameters. I want to get rid of dependencies in my code, so I put all my interface dependencies in the constructor and want to use structuremap to handle this for me. I have used this in a semi-large project, but in this blog post I will use an example with only one dependency and only one page.

Lets get started:

I start by creating a new ASP.NET MVC project. I then delete all controllers and views except for my home controller and my index view.

Then I add a Tools folder and a PersonRepository class in my new folder. This only has a default constructor and a get method that returns a Person, a simple object with only a name Property. I also extract an interface from PersonRepository called IPersonRepository.

In my homecontroller I create a constructor that takes a Ipersonrepository as a parameter. This is my HomeController now:

using System.Web.Mvc; using DIControllerFactoryExample.Tools; namespace DIControllerFactoryExample.Controllers
{ public class HomeController
: Controller { private readonly IPersonRepository
personRepository; public HomeController(IPersonRepository
personRepository) { this.personRepository = personRepository;
} public ActionResult
Index() { var personid = 1;
ViewData.Model = personRepository.Get(personid); return View();
} } }

I compile, run and get a: "No parameterless constructor defined for this object." exception. Just as planned.
Now, the fun begins. Getting this to work.

I start by adding a solution folder called Lib, and adding StructureMap.dll and Microsoft.Practices.ServiceLocation.dll and reference them in the solution. These can be found at the locations in the top of this blog post.

Then I add 3 new files to my Tools folder.
StructureMapServiceLocator.cs, DefaultStructureMapRegistry.cs, CommonServiceLocatorControllerFactory.cs

These files look like this:

using StructureMap.Configuration.DSL; namespace DIControllerFactoryExample.Tools
{ public class DefaultStructureMapRegistry
: Registry { public DefaultStructureMapRegistry()
{ ForRequestedType<IPersonRepository>().TheDefaultIsConcreteType <PersonRepository>();
} } }using System; using System.Collections.Generic; using Microsoft.Practices.ServiceLocation; using StructureMap; namespace DIControllerFactoryExample.Tools
{ public class StructureMapServiceLocator
: ServiceLocatorImplBase { private IContainer
container; public StructureMapServiceLocator(IContainer
container) { this.container = container;
} protected override object DoGetInstance(Type
serviceType, string key)
{ return string.IsNullOrEmpty(key)
? container.GetInstance(serviceType) : container.GetInstance(serviceType, key); } protected override IEnumerable<object>
DoGetAllInstances(Type serviceType) { foreach (object obj in container.GetAllInstances(serviceType))
{ yield return obj;
} } } }

using System; using System.Web.Mvc; using Microsoft.Practices.ServiceLocation; namespace DIControllerFactoryExample.Tools
{ public class StructureMapServiceLocatorControllerFactory
: DefaultControllerFactory { protected override IController
GetControllerInstance(Type controllerType) { var controller = ServiceLocator.Current.GetInstance(controllerType) as Controller; return controller;
} } }

I also add the following to the Application_Start method in my Global.asax.cs:

var
registry = new DefaultStructureMapRegistry();
var container = new Container(registry);
ServiceLocator.SetLocatorProvider(() => new StructureMapServiceLocator(container));
var locator = new StructureMapServiceLocatorControllerFactory();
ControllerBuilder.Current.SetControllerFactory(locator);

I compile, reload and everything works. That's is. Good luck;)

EDIT: Did a small fix in the code i global.asax, check out this post

The full Visual Studio solution can be downloaded here:

DIControllerFactoryExample.zip (463.5 KB)

Adding a custom route to ASP.NET MVC to allow old .aspx urls to work.

Gaute Magnussen — Fri, 05 Jun 2009 16:43:20 GMT

I have recently been working on a project where we reimplement an old web application with a new one. Since there has been an page on the same address before, there are also some old applications in other places linking to pages on the old site. For instance, the login.aspx file is linked to in a lot of places.

I will in my example use a link to the page login.aspx in my solution.

To get these links to work, I had (as far as I'm aware of) two options. To make a login.aspx and redirect in this file and add login.aspx to global.asax IgnoreRoute, or to map a new route in global.asax and redirect to my new login. The latter is the solution i went for.

To accomplish this all I had to do was to add the following to RegisterRoutes method in global asax:

routes.MapRoute("Handle login", "login.aspx", new { controller = "Login", action = "Index", id = "" });

Very easy, and now, every request for http://myapp/login.aspx is handled by http://myapp/login/index/

"String was not recognized as a valid DateTime" from Telerik Calendar Datepicker

Gaute Magnussen — Tue, 28 Oct 2008 20:20:13 GMT

Today I got an error on a web application after upgrading it from .Net 2.0 and Visual Studio 2005 to .Net 3.5. The project uses Telerik radcontrol, a few releases old version. After upgrading, every page that uses the radcontrol DatePicker failed to load, and the dreaded "Yellow screen of death" was shown instead.

It wasen't my code that failed, it was the radcontrols own prerender-event that threw the exception. Since I don't have the source code for this control and due to the fact that the fault only appaired on one test server without Visual Studio installed, it was hard to debug. Luckily a colleague had experienced a similair problem some weeks ago, and I remembered that changing the locale settings helped him (He is swedish, and used a swedish locale in an otherwise homogenic norwegian development team).

I logged in to the server and tried to change the system locale of the admin user. No help.
I tried to change the user running the application pool from NETWORK SERVICE to the admin I logged in as. Suddenly everything worked.

I did however want to run the process as NETWORK SERVICE and not administrator or have to make another account just for this reason. Therefore I wanted to change the network services locale settings, but since this is a user you can't log in as, this seemed hard.

Luckily I found this blog post: IIS6: Changing the Locale ID when Regional Settings Won't Work
I followed the description to change the settings. For some reason this didn't quite work. Probably due to a typo. I tried to export the regedit settings for HKEY_USERS\S-1-5-20 and just manually change the sShortDate, from the English setting and to norwegian settings. Now everything is working again!

Stay away from DataBinder.Eval, use explicit casting

Gaute Magnussen — Wed, 03 Sep 2008 18:42:36 GMT

All most every ASP.NET website I have seen, uses Databinder.Eval(Container.DataItem, "colum1") in repeaters to get the data passed in and show it on screen. The problem with Databinder.Eval is that it uses reflection to evaluate the item. This is time consuming and unnecessary, so instead, one should use casting to obtain the same effect. Try not to do it this way:

<asp:repeater
id="rptAccounts" runat="server">
    <itemtemplate>         <%#
Databinder.Eval(Container.DataItem, "colum1")
%> <br />     </itemtemplate> </asp:repeater>

But use this one instead:

<asp:repeater
id="rptAccounts" runat="server">

    <itemtemplate>

        <%# ((BusinessObjects.Object)Container.DataItem).Column1
%> <br />

    </itemtemplate>

</asp:repeater>





This will also give you a compiler warning if the members of a class should change,
and

not just runtime fail such as the first example. If you are not using business

objects, but a DataTable, you can  cast

to datarow and get the column right out of there like this:











<asp:repeater
id="rptAccounts" runat="server">
    <itemtemplate>         <%#
((DataRow)Container.DataItem)["Column1"]
%> <br />     </itemtemplate> </asp:repeater> 


This both increases speed and makes the application more robust to runtime errors.
A win-win situation:)

Calendar control

Gaute Magnussen — Fri, 25 Jul 2008 16:20:21 GMT

I have been struggling a couple of hours to get the calendar control in .Net to meet my requirements. What I needed was a control to select a date, so a DateTimePicker would be great. This does not exist in the ASP framework, so I needed to use the calendar control or buy some third party tool.

My requirements was that only dates within a given time frame should be clickable. The next and previous month button should also only be clickable if there were clickable dates in these months. The solution came to me in a dream, no actually a colleague got me on the idea. The answer was in the events.

Heres the code:

private void calDueDate_DayRender(object sender,
System.Web.UI.WebControls.DayRenderEventArgs e) { DateTime dt = Convert.ToDateTime(
dueDate ); if(
dt <= DateTime.Today.AddDays(30) ){ e.Day.IsSelectable = false;
} } private void calDueDate_VisibleMonthChanged(object sender,
System.Web.UI.WebControls.MonthChangedEventArgs e) { DateTime dt = Convert.ToDateTime(
pageTask.DueDate); if(
dt <= DateTime.Today){ calDueDate.NextMonthText= "" calDueDate.NextMonthText= ">";
} else{
calDueDate.NextMonthText = "";
calDueDate.PrevMonthText = "<";
} } private void calDueDate_Load(object sender,
System.EventArgs e) { calDueDate.PrevMonthText = "";
}

I must say, the AJAX Calendar looks pretty sweet as well: http://ajax.asp.net/ajaxtoolkit/Calendar/Calendar.aspx