ParameterDirection.ReturnValue 的使用

1 Public Function ExchangeBedFromWard(ByVal fromResourceID As String, ByVal toResourceID As String, _
 2                                        ByVal fromBookignID As String, ByVal toBookingID As String) As Integer
 3        Dim sp As String = "enterprise.Booking_ExchangeBedForWard"
 4        Try
 5            Using con As New SqlConnection(connectionString)
 6                Using cmd As New SqlCommand(sp, con)
 7                    con.Open()
 8                    cmd.Parameters.Add(New SqlParameter("@FromBookingID", SqlDbType.NVarChar)).Value = fromBookignID
 9                    cmd.Parameters.Add(New SqlParameter("@ToBookingID", SqlDbType.NVarChar)).Value = toBookingID
10                    cmd.Parameters.Add(New SqlParameter("@FromResourceID", SqlDbType.NVarChar)).Value = fromResourceID
11                    cmd.Parameters.Add(New SqlParameter("@toResourceID", SqlDbType.NVarChar)).Value = toResourceID
12                    cmd.Parameters.Add(New SqlParameter("RETURN_VALUE", SqlDbType.Int)).Direction = ParameterDirection.ReturnValue   '返回数据库中return的值
13                    cmd.CommandType = CommandType.StoredProcedure
14                    cmd.ExecuteNonQuery()
15                    Return Convert.ToInt32(cmd.Parameters("RETURN_VALUE").Value)
16                End Using
17            End Using
18        Catch ex As Exception
19            Return -1
20        End Try
21    End Function