public class AppointmentCRUDEventArgs :
    RoutedEventArgs

Public Class AppointmentCRUDEventArgs
    Inherits RoutedEventArgs

// data context
public class SchedulingContext : DbContext {
    public SchedulingContext() : base(CreateConnection(), true) { }
    static DbConnection CreateConnection() {
        //...
    }
    public DbSet<AppointmentEntity> AppointmentEntities { get; set; }
    public DbSet<ResourceEntity> ResourceEntities { get; set; }
}

// save changes to the data source
public void ProcessChanges(AppointmentCRUDEventArgs args) {
    using(var dbContext = new SchedulingContext()) {
        dbContext.AppointmentEntities.AddRange(args.AddToSource.Select(x => (AppointmentEntity)x.SourceObject));

        foreach(var appt in args.UpdateInSource.Select(x => (AppointmentEntity)x.SourceObject))
            AppointmentEntityHelper.CopyProperties(appt, dbContext.AppointmentEntities.Find(appt.Id));

        foreach(var appt in args.DeleteFromSource.Select(x => (AppointmentEntity)x.SourceObject))
            dbContext.AppointmentEntities.Remove(dbContext.AppointmentEntities.Find(appt.Id));

        dbContext.SaveChanges();
    }
}

' data context
Public Class SchedulingContext
    Inherits DbContext

    Public Sub New()
        MyBase.New(CreateConnection(), True)
    End Sub
    Private Shared Function CreateConnection() As DbConnection
        '...
    End Function
    Public Property AppointmentEntities() As DbSet(Of AppointmentEntity)
    Public Property ResourceEntities() As DbSet(Of ResourceEntity)
End Class

' save changes to the data source
Public Sub ProcessChanges(ByVal args As AppointmentCRUDEventArgs)
    Using dbContext = New SchedulingContext()
        dbContext.AppointmentEntities.AddRange(args.AddToSource.Select(Function(x) CType(x.SourceObject, AppointmentEntity)))

        For Each appt In args.UpdateInSource.Select(Function(x) CType(x.SourceObject, AppointmentEntity))
            AppointmentEntityHelper.CopyProperties(appt, dbContext.AppointmentEntities.Find(appt.Id))
        Next appt

        For Each appt In args.DeleteFromSource.Select(Function(x) CType(x.SourceObject, AppointmentEntity))
            dbContext.AppointmentEntities.Remove(dbContext.AppointmentEntities.Find(appt.Id))
        Next appt

        dbContext.SaveChanges()
    End Using
End Sub