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（读者可打开【光盘】｜【源文件】｜【实例 96 】｜【 96.4.txt 】文件，直接复制） [page_break] （ 4 ）定义“ Roomcheck ”函数。该函数首先检测用户有没有选择预订客房类型，如果没有选择，则该函数返回“ False ”，接着在用户选择预订客房类型的情况下，检测所选择的客房类型在预订的时间段中是否已预订满，如果是，则返回“ False ”，否则将返回“ True ”，该函数的代码如下所述。
Function Roomcheck() As Boolean
Dim Hotelada1, Hotelada2 As OleDbDataAdapter
Dim HotelDataSet1, HotelDataSet2 As System.Data.DataSet
Dim Hoteldt1, Hoteldt2 As DataTable
Dim i, RoomI As Integer
If RoomRadio.SelectedItem.Value <> Nothing Then
Hotelstring = "Select * From UserOrder Where RoomID=" & RoomRadio.SelectedItem.Value
Hotelada1 = New OleDbDataAdapter(Hotelstring, conn)
HotelDataSet1 = New System.Data.DataSet
Hotelada1.Fill(HotelDataSet1, "UserOrder")
Hoteldt1 = HotelDataSet1.Tables("UserOrder")
Dim Date1, Date2 As Date
Date1 = StartTime.Text
Date2 = LastTime.Text
For i = 0 To Hoteldt1.Rows.Count - 1
Dim roomdate1, roomdate2 As Date
roomdate1 = Hoteldt1.Rows(i)("StartTime")
roomdate2 = Hoteldt1.Rows(i)("LastTime")
If (System.DateTime.Compare(Date1, roomdate1) And System.DateTime.Compare(roomdate2, Date1)) _
Or (System.DateTime.Compare(Date2, roomdate1) And System.DateTime.Compare(roomdate2, Date2)) _
Or (System.DateTime.Compare(roomdate1, Date1) And System.DateTime.Compare(Date2, roomdate2)) Then
RoomI += 1
End If
Next
Hotelstring = "select RoomNum From tbRoom where RoomID=" & RoomRadio.SelectedItem.Value
Hotelada2 = New OleDbDataAdapter(Hotelstring, conn)
HotelDataSet2 = New System.Data.DataSet
Hotelada1.Fill(HotelDataSet2, "tbRoom")
Hoteldt2 = HotelDataSet2.Tables("tbRoom")
If RoomI +CInt(OrderNum.Text) > Hoteldt2.Rows(0)("RoomNum") Then
Roomcheck = False
Exit Function
End If
Else
Roomcheck = False
Exit Function
End If
Roomcheck = True
End Function |
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