Conversion from string "Timeofday" to type 'Integer' is not valid.

 dvholidays = New DataView(dtholidays, "Date = '" & CDate(e.Day.Date) & "' and Username = 'Perkinsj'", "", DataViewRowState.CurrentRows)

            If dvholidays.Item("Timeofday").ToString IsNot "" Then
                Dim iamoff As String = dvholidays.Item("Timeofday").ToString
                '  Dim iamoff As String = dateallreadybooked.havei(e.Day.Date, "Perkinsj")
                Select Case iamoff
                    Case "Am"
                        am.ImageUrl = "Images/Dark_Blue_Button.jpg"
                        am.Enabled = True ' enable the button so the user can change this if they no longer want the day booked
                    Case "Pm"
                        pm.ImageUrl = "Images/Dark_Blue_Button.jpg"
                        pm.Enabled = True ' enable the button so the user can change this if they no longer want the day booked
                    Case "full"
                        full.ImageUrl = "Images/Dark_Blue_Buttonlarge.jpg"
                        full.Enabled = True ' enable the button so the user can change this if they no longer want the day booked
                End Select
            End If