Error while creating context in Entity Framework - wpf

Question

I am developing a WPF application that uses Entity Framework v.6 with the approach Code First to build and manage a local database which is created on the client computer itself.
When I install the application on a client computer and launch it, I receive the following error when the context tries to create the database:
Expansion of |DataDirectory| failed while processing the connection string. Ensure that |DataDirectory| is set to a valid fully-qualified path.
In app.config I have set the following configuration of Entity Framework:
<entityFramework>
<defaultConnectionFactory type="System.Data.Entity.Infrastructure.LocalDbConnectionFactory, EntityFramework">
<parameters>
<parameter value="mssqllocaldb"/>
</parameters>
</defaultConnectionFactory>
<providers>
<provider invariantName="System.Data.SqlClient" type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer"/>
</providers>
</entityFramework>
My context class contains the following code:
class EntityContext : DbContext
{
public DbSet<Car> Cars { get; set; }
public DbSet<Trip> Trips { get; set; }
public DbSet<Volunteer> Volunteers { get; set; }
public DbSet<Motivation> Motivations { get; set; }
public DbSet<PaymentType> PaymentTypes { get; set; }
public EntityContext() : base("StaccoDataBase")
{
System.Data.Entity.Database.SetInitializer(new CreateDatabaseIfNotExists<EntityContext>());
}
}
I have tried to fix the problem setting the |DataDirectory| in the App.xaml.cs as follows:
protected override void OnStartup(StartupEventArgs e)
{
base.OnStartup(e);
AppDomain currentDomain = AppDomain.CurrentDomain;
currentDomain.SetData("DataDirectory", Directories.DBDirectory);
}
But the issue still persists.
I would really appreciate if someone can help me.

Answer 1

Just a wild guess - what if you used this connection string:
Data Source=(LocalDb)\\MSSQLLocalDB; AttachDBFilename=|DataDirectory|StaccoDataBase.mdf; integrated security=SSPI
First of all, use the |DataDirectory| directly in your connection string (don't "inject" it via that string.Format() call), and secondly, add the .mdf extension to the database file you want to attach.
Also, I'd store this connection string in the app.config - don't create it at runtime, because the constructor call here:
public EntityContext() : base("StaccoDataBase")
will try to find StaccoDataBase as a connection string name in your config file.
So use this:
app.config:
<configuration>
.....
<connectionStrings>
<add name="StaccoDataBase"
connectionString="Data Source=(LocalDb)\\MSSQLLocalDB;AttachDBFilename=|DataDirectory|StaccoDataBase.mdf; integrated security=SSPI"
providerName="System.Data.SqlClient" />
<connectionStrings>
.....
</configuration>