The Digital Tool Factory Blog

The Problem:

So, you’re coding away, and you run your asp.net mvc 4 site and you get the following error: The system cannot find the path specified

The Cause:

Most likely you have not already specified the database in the web.config, it’s a simple fix.

The Solution:

Just add this code into the web.config

<add name=”BlogProphetsiteContext” connectionString=”Server=.SQLEXPRESS;Database=BlogProphetsite;Trusted_Connection=true;MultipleActiveResultSets=true” providerName=”System.Data.SqlClient” />

and all will be good. For some reason it does not automatically generate one for you.

The Problem

So, you are tooling around in asp.net mvc 3 Entity Framework Code First, and you make a change to your underlying model.  you then get the following error when Entity Framework tries to recreate the database in Sql Server or Sql Server Express

Model compatibility cannot be checked because the database does not contain model metadata. Ensure that IncludeMetadataConvention has been added to the DbModelBuilder conventions.

The Cause

You still have some lock on the database in some way, perhaps you still have the database open in Visual Studio (it is very easy to do this in Visual Studio 2010) or perhaps you have it open in a Sql Server Management Studio window.  Perhaps Windows just doesn’t like you.  In any case, it’s that database is open, and Entity Framework Code First will not drop the database if anyone is still using it.

The Solution

You have to release all locks and holds on the database before Entity Framework Code First will drop the database.  To do that, open up Sql Server Management Studio and paste in the following code

USE [master]
GO

/****** Object: Database [MyDBname] Script Date: 02/24/2012 13:54:40 ******/
ALTER DATABASE [MyDBname] SET SINGLE_USER WITH ROLLBACK IMMEDIATE
ALTER DATABASE [MyDBname] SET SINGLE_USER WITH NO_WAIT
DROP DATABASE [MyDBname]
GO

That will isolate your database (please note that “MyDBName” is where you should put your database name) and allow Entity Framework CodeFirst to drop and recreate the database and implement your changes.  Doing this WILL drop the database, so be careful.

The Problem

You want to create urls that look something like http://SomeSite.com/Categories/Industrial/Fasteners/3.8-MM-Titanium-Wrench-Bolts/ so your site can rank extra high when people search for those profitable 3.8 MM Titanium Wrench Bolts. And in natural, RESTful fashion, your site and database is structured so that the Wrench Bolts are in a subcategory of Fasteners, which are part of the Industrial Category

The Cause:

None really, I’m just listing how one does this sort of thing.

The Solution

Firstly you have to define your route in your global.asax file, in the Register Routes section

routes.MapRoute(
“ItemInd”, // Route name
“Categories/{CategoryName}/{SubCategoryName}/{id}”, // URL with parameters
new { controller = “Product”, action = “Details”, CategoryName = “”, SubCategoryName = “”, id = “” } // Parameter defaults
);

a
Then you have to set your Route Values
Here is an ActionLink helper –

@Html.ActionLink(p.Name, “Details”, new { controller = “Product”, action = “Details”, CategoryName = p.SubCategory.Category.Name, SubCategoryName = p.SubCategory.Name, id = p.Name })

And if you want to use the URL.Action helper, here is what that would look like.

<a href=”@Url.Action(“Details”, “Product”, new { controller = “Product”, action = “Details”, CategoryName = p.SubCategory.Category.Name, SubCategoryName = p.SubCategory.Name, id = p.Name })”>Some Text</a>

as you might suspect, the new { controller = “Product”, action = “Details”, CategoryName = p.SubCategory.Category.Name, SubCategoryName = p.SubCategory.Name, id = p.Name } maps exactly to the corresponding parts in the global.asax file.

This wasn’t really a how to fix problem, but really more about using asp.net mvc 3 RouteValues.  I’ve found a lack of documentation on how to make relatively complicated urls, so I thought this would be a start!