WPF : Use NpgSQL Entity Framework - wpf

Question

I would like to upgrade my app made using Windows Forms to WPF. I face an issue with the Postgres Entity Framework v6.
Under Winforms, it works perfectly. I use the app.config file to set the connection up.
Unfortunately, it does not under WPF. I installed the NuGet package System.Configuration.ConfigurationManager. I get an error
'System.Configuration.ConfigurationErrorsException'
'System.Windows.Markup.XamlParseException' in PresentationFramework.dll
when calling the MainContext constructor.
Winforms - app.config:
<?xml version="1.0" encoding="utf-8"?>
<configuration>
<configSections>
<section name="entityFramework"
type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />
</configSections>
<startup>
<supportedRuntime version="v5.0" sku=".NETFramework,Version=v5.0" />
</startup>
<entityFramework>
<providers>
<provider invariantName="System.Data.SqlClient"
type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer" />
<provider invariantName="Npgsql"
type="Npgsql.NpgsqlServices, EntityFramework6.Npgsql" />
</providers>
<defaultConnectionFactory type="Npgsql.NpgsqlConnectionFactory, EntityFramework6.Npgsql" />
</entityFramework>
<connectionStrings>
<add name="Default"
connectionString="host=localhost;port=5432;database=MyDatabase;user id=MyUserName;password=MyPassword"
providerName="Npgsql" />
</connectionStrings>
<system.data>
<DbProviderFactories>
<remove invariant="Npgsql" />
<add name="Npgsql Provider" invariant="Npgsql" description=".NET Framework Data Provider for PostgreSQL" type="Npgsql.NpgsqlFactory, Npgsql, Version=4.1.3.0, Culture=neutral, PublicKeyToken=5d8b90d52f46fda7" />
</DbProviderFactories>
</system.data>
<runtime>
....
</runtime>
</configuration>
The DbContext class :
public class MainContext : DbContext, IDbContext
{
public MainContext() : base(nameOrConnectionString: "Default") // <== Here is the crash
{
this.Configuration.LazyLoadingEnabled = false;
}
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
base.OnModelCreating(modelBuilder);
}
public DbSet<Agent> agents { get; set; }
}
Updated :
After hours, i found a solution for the System.data exception. Declare the section <system.data> in the section configSections like below
<configSections>
<section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />
<section name="system.data" type="System.Data.Common.DbProviderFactoriesConfigurationHandler, System.Data, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />
</configSections>
Unfortunetly now i got another error :
Exception :
ArgumentException : The specified invariant name 'Npgsql' wasn't found in the list of registered .NET Data Providers.
Inner Exception :
"The ADO.NET provider with invariant name 'Npgsql' is either not registered in the machine or application config file, or could not be loaded. See the inner exception for details."
Final Update :
Finaly i found the problem. I created a WPF project instead WPF .Net Framework project
Thank you for your help.