entity framework code first migrations from seperate windows class library - entity-framework

Question

i have a solution that contains an MVC project and windows class library project that uses entity framework and is a data access layer. I tried to enable migrations with the following package manager console line
Enable-Migrations -ProjectName PortlandRoad.DAL -ContextTypeName PortlandRoadDBContext -Force
I try to update the database using the following line
Update-Database -Verbose -Force
if i do this with the mvc project as the startup project it works, but uses the connection string in the mvc project web.config. If i do this with the dAL project as the startup project i get the following error :
A file activation error occurred. The physical file name '\PortlandRoadDB.mdf' may be incorrect. Diagnose and correct additional errors, and retry the operation.
CREATE DATABASE failed. Some file names listed could not be created. Check related errors.
the app.config file for my DAL project is as follows :
<?xml version="1.0" encoding="utf-8"?>
<configuration>
<configSections>
<!-- For more information on Entity Framework configuration, visit http://go.microsoft.com/fwlink/?LinkID=237468 -->
<section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=5.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />
<!--<section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=5.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />-->
</configSections>
<connectionStrings>
<add name="DefaultConnection" connectionString="Data Source=(LocalDb)\v11.0;Initial Catalog=PortlandRoadDB;Integrated Security=SSPI;AttachDBFilename=|DataDirectory|\PortlandRoadDB.mdf" providerName="System.Data.SqlClient" />
</connectionStrings>
<entityFramework>
<defaultConnectionFactory type="System.Data.Entity.Infrastructure.LocalDbConnectionFactory, EntityFramework">
<parameters>
<parameter value="v11.0" />
</parameters>
</defaultConnectionFactory>
</entityFramework>
</configuration>
can anybody tell me how to correct this so that the migrations work specifically for the dal project and are not dependent on the MCV project being the startup project
thanks

Answer 1

I've the same issue in a WPF project.
I think that you have two options.
Option 1
At startup in you windows project try to specify the correct path to your database using
AppDomain.CurrentDomain.SetData("DataDirectory","your\physical\path");
With this, you will have the same error but your migrations can still being applied to your principal database.
option 2
Find a way to replace dynamically this |DataDirectory| in your app.config file before starting your application. (.bat , or .ps or ...).
another option: The bad one.
Before running your migration change the path to you DataDirectory to a physical temporary one in your app.config (this file will help you keep up to date migrations history)
before launching your application replace the temporary file path by |DataDirectory| and change this parameter in your startup with the App.config
With this work around, if your are planning to deploy your application, you will keep track of all migrations in order to anticipate futures database modifications.
Voilà.

Answer 2

Could it be that you're using "|DataDirectory|" in the connection string in the DAL project? Since "|DataDirectory|" is an Asp.Net folder and the DAL project is not an Asp project it probably doesn't recognize that as a directory and it probably doesn't exist thing the DAL project.