我是编程新手,并且在VB.net中编写的Web应用程序出现问题。我在我的项目中有一个Access数据库,并使用参数化查询从它检索信息。奇怪的是,我在另一个页面上使用几乎相同的查询,但工作正常,但是这给了我一个或多个所需参数没有给出值的错误。我一直在大部分时间都在搜索,并意识到问题已被问到,但无法找到解决我的问题的方法。我想我正在使用“?”正确地说,按照正确的顺序有正确数量的参数,并且一切拼写正确。这里是我的代码:OLEDBException:在vb.net中没有给出一个或多个必需参数的值
Dim strWthStn As String
strWthStn = cboRainProb2.Text
Dim strWthStnParm As New OleDb.OleDbParameter()
strWthStnParm.Value = strWthStn
Dim strMonth As String
strMonth = cboRainProb.Text
Dim strMonthParm As New OleDb.OleDbParameter()
strMonthParm.Value = strMonth
Dim sql As String 'Query to select the station for rainfall probability values
sql = "SELECT 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 " &
"FROM Rainfall Probability " &
"WHERE Station = ?" &
"AND Mth = ?"
'Connects to the Access database and selects data based on query
Dim AccessConnect As String
AccessConnect = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=F:\Megan\Visual Studio Projects\DroughtCalculatorND_Web\DroughtCalculatorND_Web\NDStations.mdb"
Dim conn As New OleDb.OleDbConnection
Dim selectCommand As New OleDbCommand(sql, conn)
selectCommand.Parameters.Add(strWthStnParm)
selectCommand.Parameters.Add(strMonthParm)
conn.ConnectionString = AccessConnect
conn.Open()
'Reads the data into a list
Dim reader As OleDbDataReader =
selectCommand.ExecuteReader(CommandBehavior.CloseConnection)
Dim RainByYear As New List(Of Double)
reader.Read()
RainByYear.Add(reader("1999"))
RainByYear.Add(reader("2000"))
RainByYear.Add(reader("2001"))
RainByYear.Add(reader("2002"))
RainByYear.Add(reader("2003"))
RainByYear.Add(reader("2004"))
RainByYear.Add(reader("2005"))
RainByYear.Add(reader("2006"))
RainByYear.Add(reader("2007"))
RainByYear.Add(reader("2008"))
RainByYear.Add(reader("2009"))
RainByYear.Add(reader("2010"))
RainByYear.Sort()
等
处OleDBDataReader线昏暗的读者的程序错误。我用了一个断点来检查一切,两个参数都有正确的值。我感谢任何帮助,谢谢。
什么叫 “正确的价值” 是什么意思? – luchosrock 2013-04-04 21:43:01