Compare DateTime (LINQ, Entity Framework)

        private void frmMain_Load(object sender, EventArgs e)
        {
            // Create new entities Object
            using (var db = new myDatabaseEntities())
            {
                // DateTime
                DateTime? dtFrom = null;
                DateTime? dtTo = Convert.ToDateTime("15-Aug-2015");

                // Get data from AUDIT
                var ds = (from c in db.AUDIT
                          select c).ToList();

                // Compare From
                if (dtFrom != null)
                {
                    ds = ds.Where(o => (o.LOG_DATE >= dtFrom)).ToList();
                }

                // Compare To
                if (dtTo != null)
                {
                    ds = ds.Where(o => (o.LOG_DATE <= dtTo)).ToList();
                }

                // if found item rows
                if (ds.Count() > 0)
                {
                    this.myDataGridView.DataSource = ds;
                }
            }
        }

    Private Sub frmMain_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        ' Create new entities Object
        Using db = New myDatabaseEntities()
            ' DateTime
            Dim dtFrom? As DateTime = Nothing
            Dim dtTo? As DateTime = Convert.ToDateTime("15-Aug-2015")

            ' Get data from AUDIT
            Dim ds = (From c In db.AUDIT Select c).ToList()

            ' Compare From
            If Not IsNothing(dtFrom) Then
                ds = ds.Where(Function(o) (o.LOG_DATE >= dtFrom)).ToList()
            End If

            ' Compare To
            If Not IsNothing(dtTo) Then
                ds = ds.Where(Function(o) (o.LOG_DATE <= dtTo)).ToList()
            End If

            ' if found item rows
            If ds.Count() > 0 Then
                Me.myDataGridView.DataSource = ds
            End If
        End Using
    End Sub