How to dynamically pass connectionstrings in EF5 - wpf

Question

I'm struggling with a project, converted to .net 4.5.
I have some functions like this:
Public Shared Function Load(iJaar As Integer, iKwartaal As Integer) As List(Of LoonDetail_121)
Dim oLoonDetails As New List(Of LoonDetail_121)
Try
Dim oDB As New SDWMasterSDWDBEntities(DBConnections.ConnStringPrisma)
Dim dStartDate As New Date(iJaar, ((iKwartaal - 1) * 3) + 1, 1)
Dim dEndDate As New Date(iJaar, ((iKwartaal - 1) * 3) + 4, 1)
oLoonDetails = oDB.LoonDetail_121.Where(Function(x) x.EindPeriode_121 >= dStartDate And
x.EindPeriode_121 < dEndDate).ToList
Catch ex As Exception
Throw New Exception(GetCurrentMethod.Name & " " & ex.Message)
End Try
Return oLoonDetails
End Function
When I convert this function to EF5, I get errors, since my SDCDBLonenEntities is not inherited anymore from ObjectContext, but it is inherited from DbContext.
Before, EF automatically created a constructor where I can pass my Connection String.
This is very easy, because I use different connectionstrings, depending on my Solution Configuration (Debug/Release).
In EF5, the constructor doesn't accept Connectionstrings anymore.
I tried to create a partial class of my Entity, and create my own constructor, but I can't get this working:
Partial Public Class SDWMasterSDWDBEntities
Inherits DbContext
Public Sub New(sConnString As String)
MyBase.New(sConnString)
End Sub
End Class
For another project, I adapted my Project-file to use different app.config files for each solution configuration, but that was a p.i.t.a to maintain and for me not a clean solution.
So my question is: How can I use EF5 with my own personal Connectionstrings?
These are my Connection Strings by the way:
#If DEBUG Then
Friend ConnStringSDW As String = "metadata=res://*/Entities.SDWDB.csdl|res://*/Entities.SDWDB.ssdl|res://*/Entities.SDWDB.msl;provider=System.Data.SqlClient;provider connection string='data source=SDWDB01\SDWSQL;initial catalog=SDWDB_DEV;persist security info=True;user id=usr;password=pwd;multipleactiveresultsets=True;App=EntityFramework'"
#Else
Friend ConnStringSDW As String = "metadata=res://*/Entities.SDWDB.csdl|res://*/Entities.SDWDB.ssdl|res://*/Entities.SDWDB.msl;provider=System.Data.SqlClient;provider connection string='data source=SDWDB01\SDWSQL;initial catalog=SDWDB_PROD;persist security info=True;user id=usr;password=pwd;multipleactiveresultsets=True;App=EntityFramework'"
#End If
And I get the error "The entity type SDW_USERS_MASTER is not part of the model for the current context.", when I execute this function:
Public Shared Function LoadAll() As List(Of SDW_USERS_MASTER)
Dim oUsers As New List(Of SDW_USERS_MASTER)
Try
Using oDB As New SDWMaster.SDWMasterSDWDBEntities(DBConnections.ConnStringSDW)
oUsers = (From tmpUsers In oDB.SDW_USERS_MASTER
Select tmpUsers).ToList.OrderBy(Function(x) x.Login).ToList
End Using
Catch ex As Exception
Debug.Print(ex.Message)
Throw New Exception(GetCurrentMethod.Name & " " & ex.Message)
End Try
Return oUsers
End Function

Answer 1

Create a new partial class with the same name as your context, then overload the constructor. So, if your context class is named "myContext", then you would have:
Imports System
Imports System.Data.Entity
Imports System.Data.Entity.Infrastructure
Imports System.Data.Objects
Imports System.Data.Objects.DataClasses
Imports System.Linq
Partial Public Class myContext
Inherits DbContext
Public Sub New(connectionString As String)
MyBase.New(connectionString)
End Sub
End Class