0
時,具有相同密鑰的項目已被添加錯誤我在FormMain_load子內部有這些代碼行。即使當我清除
在第一次加載時,程序正常工作。然後我嘗試打開另一個表單並再次調用FormMain。這一次,表單顯示錯誤,具有相同鍵的項目已被添加。我試圖在子的第一行上清楚字典,但它仍然顯示相同的錯誤。然後,我還嘗試清除字典,然後重新添加,但仍然失敗。奇怪的是消息框顯示錯誤發生之前字典計數爲0。
query = "SELECT * FROM transaction WHERE isPaid=0"
If myConn.State = ConnectionState.Closed Then
myConn.Open()
End If
If myCommand Is Nothing Then
myCommand = New MySqlCommand(query, myConn)
Else
myCommand.CommandText = query
End If
myDataReader = myCommand.ExecuteReader
If myDataReader.HasRows Then
While myDataReader.Read()
transactionUnpaid.Enqueue(myDataReader("transaction_id"))
End While
myDataReader.Close()
roomList.Clear()
MsgBox(roomList.Count())
For Each a As Integer In transactionUnpaid
query = "SELECT * FROM room_ol WHERE transaction_id=" & a
If myConn.State = ConnectionState.Closed Then
myConn.Open()
End If
If myCommand Is Nothing Then
myCommand = New MySqlCommand(query, myConn)
Else
myCommand.CommandText = query
End If
myDataReader = myCommand.ExecuteReader
myDataReader.Read()
roomList.Add(myDataReader("room_id"), myDataReader("transaction_id"))
myDataReader.Close()
Next
End If
If Not myDataReader.IsClosed Then
myDataReader.Close()
End If