System.NullReferenceException 未将对象引用设置到对象的实例 - 编程论坛

#2

biwysh2008-05-22 13:27

各位老师帮忙看看，我是初学者，老师让弄一个注册的网页，这点出错了，搞不明白ConnDB()
是一个vb的类就是把接数据库一些函数封装到这个类里
Imports Microsoft.VisualBasic
Imports System.Data.OleDb
Imports System.Data
Public Class ConnDB
    Inherits System.Web.UI.Page

    Private connStr As String
    Private objCon As OleDbConnection
    Private objCmd As OleDbCommand
    Private objDS As Data.DataSet
    Private objDR As OleDbDataReader
    Private objDA As OleDbDataAdapter


    Public Sub New()
        connStr = "Provider=" & System.Web.Configuration.WebConfigurationManager.ConnectionStrings("servername").ProviderName
        connStr &= "Data Source=" & System.Web.HttpContext.Current.Server.MapPath(System.Web.Configuration.WebConfigurationManager.ConnectionStrings("severname").ConnectionString())
        objCon = New OleDbConnection(connStr)
    End Sub
    Public Sub DBOpen()
        '打开数据库连接
        objCon.Open()
    End Sub
    Public Sub DBclose()  '关闭数据库
        Try
            objCon.Close()
        Catch ex As Exception
            objCon.Dispose()
        End Try
    End Sub

    Public Function getDataSet(ByVal sql As String) As DataSet
        If objCon.State = ConnectionState.Closed Then
            DBOpen()
        End If
        objDA = New OleDbDataAdapter(sql, objCon)
        objDS = New DataSet()
        objDA.Fill(objDS, "regedit")
        Return objDS
    End Function

#3

biwysh2008-05-22 13:29

下面是主页的代码，高手帮忙分析一下，急用
Imports System.Data.OleDb
Imports System.Data
Imports Microsoft.VisualBasic
Partial Class regedit
    Inherits System.Web.UI.Page

    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        If Page.IsPostBack Then
            Dim conn As ConnDB = New ConnDB()
            Dim strSQL As String
            conn.DBOpen()
            strSQL = "SELECT * FROM regedit"
            Dim datast As DataSet = New DataSet()
            datast = conn.getDataSet(strSQL)
            Dim objDTrow As DataRow
            objDTrow = datast.Tables("regedit").NewRow
            objDTrow("id") = id.Text
            objDTrow("pass") = pass.Text
            Dim email As String
            email = email1.Text & "@" & email2.Text
            objDTrow("email") = email
            datast.Tables("regedit").Rows.Add(objDTrow)
            conn.DBclose()
        End If

    End Sub
End Class

#4

残影留香2008-05-22 13:45

路径不对，仔细检查一下！