Set dynamic connection string EF6

Question

I'm trying to set a connection string at runtime for EF6, using VB.NET

Partial Entities class - so I can pass in connection string.

Partial Public Class MyEntities
    Public Sub New(connectionString As String)
        MyBase.New(connectionString)
    End Sub
End Class

Code calling the class errors out

Dim entityConnectionStringBuilder = New EntityConnectionStringBuilder()

    entityConnectionStringBuilder.Provider = "System.Data.SqlClient"
    entityConnectionStringBuilder.ProviderConnectionString = "Server=myServer;Database=myDatabase;User Id=myUserId;Password=myPassword;"
    entityConnectionStringBuilder.Metadata = "res://*/MyModel.csdl|res://*/MyModel.ssdl|res://*/MyModel.msl"
    Using dbContext = New MyEntities(entityConnectionStringBuilder.ToString())
        Dim staffList = (From s In dbContext.Staffs).ToList

        For Each staff1 In staffList
            Console.WriteLine(String.Format("Staff {0}", staff1.username))
        Next

    End Using

Exception:

System.Data.Entity.Core.MetadataException was unhandled
  HResult=-2146232007
  Message=Schema specified is not valid. Errors: 
MyModel.ssdl(2,2) : error 0152: No Entity Framework provider found for the ADO.NET provider with invariant name 'System.Data.SqlClient'. Make sure the provider is registered in the 'entityFramework' section of the application config file. See http://go.microsoft.com/fwlink/?LinkId=260882 for more information.
  Source=EntityFramework
  StackTrace:
       at System.Data.Entity.Core.Metadata.Edm.StoreItemCollection.Loader.ThrowOnNonWarningErrors()
       at System.Data.Entity.Core.Metadata.Edm.StoreItemCollection.Loader.LoadItems(IEnumerable`1 xmlReaders, IEnumerable`1 sourceFilePaths)
       at System.Data.Entity.Core.Metadata.Edm.StoreItemCollection.Loader..ctor(IEnumerable`1 xmlReaders, IEnumerable`1 sourceFilePaths, Boolean throwOnError, IDbDependencyResolver resolver)
       at System.Data.Entity.Core.Metadata.Edm.StoreItemCollection.Init(IEnumerable`1 xmlReaders, IEnumerable`1 filePaths, Boolean throwOnError, IDbDependencyResolver resolver, DbProviderManifest& providerManifest, DbProviderFactory& providerFactory, String& providerInvariantName, String& providerManifestToken, Memoizer`2& cachedCTypeFunction)
       at System.Data.Entity.Core.Metadata.Edm.StoreItemCollection..ctor(IEnumerable`1 xmlReaders, IEnumerable`1 filePaths)
       at System.Data.Entity.Core.Metadata.Edm.MetadataCache.LoadStoreCollection(EdmItemCollection edmItemCollection, MetadataArtifactLoader loader)
       at System.Data.Entity.Core.Metadata.Edm.MetadataCache.<>c__DisplayClass5.<>c__DisplayClass7.<GetMetadataWorkspace>b__1()
       at System.Lazy`1.CreateValue()
       at System.Lazy`1.LazyInitValue()
       at System.Data.Entity.Core.Metadata.Edm.MetadataCache.<>c__DisplayClass5.<>c__DisplayClass7.<GetMetadataWorkspace>b__4()
       at System.Data.Entity.Core.Metadata.Edm.MetadataWorkspace.LoadAndCheckItemCollection[T](Func`1 itemCollectionLoader)
       at System.Data.Entity.Core.Metadata.Edm.MetadataWorkspace.<>c__DisplayClass16.<.ctor>b__f()
       at System.Lazy`1.CreateValue()
       at System.Lazy`1.LazyInitValue()
       at System.Data.Entity.Core.Metadata.Edm.MetadataWorkspace.GetItemCollection(DataSpace dataSpace, Boolean required)
       at System.Data.Entity.Core.Metadata.Edm.MetadataWorkspace.GetItemCollection(DataSpace dataSpace)
       at System.Data.Entity.Core.Objects.ObjectContext.InitializeMappingViewCacheFactory(DbContext owner)
       at System.Data.Entity.Core.Objects.ObjectContext..ctor(EntityConnection connection, Boolean isConnectionConstructor, ObjectQueryExecutionPlanFactory objectQueryExecutionPlanFactory, Translator translator, ColumnMapFactory columnMapFactory)
       at System.Data.Entity.Core.Objects.ObjectContext..ctor(EntityConnection connection)
       at System.Data.Entity.Internal.InternalConnection.CreateObjectContextFromConnectionModel()
       at System.Data.Entity.Internal.LazyInternalConnection.CreateObjectContextFromConnectionModel()
       at System.Data.Entity.Internal.LazyInternalContext.InitializeContext()
       at System.Data.Entity.Internal.InternalContext.Initialize()
       at System.Data.Entity.Internal.InternalContext.GetEntitySetAndBaseTypeForType(Type entityType)
       at System.Data.Entity.Internal.Linq.InternalSet`1.Initialize()
       at System.Data.Entity.Internal.Linq.InternalSet`1.get_InternalContext()
       at System.Data.Entity.Infrastructure.DbQuery`1.System.Linq.IQueryable.get_Provider()
       at System.Linq.Queryable.Select[TSource,TResult](IQueryable`1 source, Expression`1 selector)
       at WpfTestDalEF6.MainWindow.Button_Click(Object sender, RoutedEventArgs e) in c:\users\arkle\documents\visual studio 2013\Projects\WpfTestDalEF6\WpfTestDalEF6\MainWindow.xaml.vb:line 14
       at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
       at System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
       at System.Windows.Controls.Button.OnClick()
       at System.Windows.Controls.Primitives.ButtonBase.OnMouseLeftButtonUp(MouseButtonEventArgs e)
       at System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)
       at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
       at System.Windows.UIElement.ReRaiseEventAs(DependencyObject sender, RoutedEventArgs args, RoutedEvent newEvent)
       at System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)
       at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
       at System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
       at System.Windows.UIElement.RaiseTrustedEvent(RoutedEventArgs args)
       at System.Windows.Input.InputManager.ProcessStagingArea()
       at System.Windows.Input.InputProviderSite.ReportInput(InputReport inputReport)
       at System.Windows.Interop.HwndMouseInputProvider.ReportInput(IntPtr hwnd, InputMode mode, Int32 timestamp, RawMouseActions actions, Int32 x, Int32 y, Int32 wheel)
       at System.Windows.Interop.HwndMouseInputProvider.FilterMessage(IntPtr hwnd, WindowMessage msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
       at System.Windows.Interop.HwndSource.InputFilterMessage(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
       at MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
       at MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o)
       at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
       at MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(Object source, Delegate method, Object args, Int32 numArgs, Delegate catchHandler)
       at System.Windows.Threading.Dispatcher.LegacyInvokeImpl(DispatcherPriority priority, TimeSpan timeout, Delegate method, Object args, Int32 numArgs)
       at MS.Win32.HwndSubclass.SubclassWndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam)
       at MS.Win32.UnsafeNativeMethods.DispatchMessage(MSG& msg)
       at System.Windows.Threading.Dispatcher.PushFrameImpl(DispatcherFrame frame)
       at System.Windows.Application.RunInternal(Window window)
       at System.Windows.Application.Run()
       at WpfTestDalEF6.Application.Main() in c:\users\arkle\documents\visual studio 2013\Projects\WpfTestDalEF6\WpfTestDalEF6\obj\Debug\Application.g.vb:line 65
       at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
       at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
       at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Threading.ThreadHelper.ThreadStart()
  InnerException: 

Any ideas on what I'm doing wrong?

Answer 1

Try reinstalling the EntityFramework NuGet Package and see if that works for you. This can be done by running the following command from the Package Manager Console:

Install-Package EntityFramework