[求助]未将对象引用设置到对象的实例。
<P>Imports System<BR>Imports System.Data<BR>Imports System.Drawing<BR>Imports System.Data.OleDb</P><P>Module ConnToDB<BR> Public ConnStr As String = "Provider=Microsoft.Jet.OLEDB.4.0;"<BR> Public ConnectStr As String = ConnStr & "Data Source=E:\寇换龙\data\student.mdb"<BR> Public DataAdapter As OleDbDataAdapter<BR> Public DataConnection As OleDbConnection<BR> Public myDataSet As DataSet<BR> Public Index As Integer<BR> Public pepdom As Integer<BR> Public No As String<BR> Public Function GetDataFromDB(ByVal sqlstr As String) As DataSet<BR> Try<BR> Dim DataConnection As OleDbConnection<BR> DataConnection.ConnectionString = ConnectStr<BR> DataAdapter = New OleDbDataAdapter(sqlstr, DataConnection)<BR> myDataSet = New DataSet<BR> DataConnection.Open()<BR> myDataSet.Clear()<BR> DataAdapter.Fill(myDataSet)<BR> DataConnection.Close()<BR> If Not (myDataSet Is Nothing) Then<BR> Return myDataSet<BR> End If<BR> Catch ex As Exception<BR> Return Nothing<BR> End Try<BR> End Function<BR> </P>
<P> Public Function UpdateDataBase(ByVal sqlstr As String) As Boolean<BR> Dim sqlconn As New OleDbConnection(ConnectStr)<BR> Try<BR> Dim cmdTable As OleDbCommand = New OleDbCommand(sqlstr, sqlconn)<BR> cmdTable.CommandType = CommandType.Text<BR> sqlconn.Open()<BR> cmdTable.ExecuteNonQuery()<BR> sqlconn.Close()<BR> Catch ex As Exception<BR> Return False<BR> End Try<BR> Return True<BR> End Function<BR>End Module<BR>Public Class WebfrmLogin<BR> Inherits System.Web.UI.Page<BR> Public sqlstr As String<BR> Public strID As String<BR> Public pwd As String<BR> Public DS As DataSet<BR> Public table As String<BR> <BR>#Region " Web 窗体设计器生成的代码 "</P>
<P> '该调用是 Web 窗体设计器所必需的。<BR> <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()</P>
<P> End Sub<BR> Protected WithEvents Image1 As System.Web.UI.WebControls.Image<BR> Protected WithEvents Label1 As System.Web.UI.WebControls.Label<BR> Protected WithEvents Image2 As System.Web.UI.WebControls.Image<BR> Protected WithEvents Label2 As System.Web.UI.WebControls.Label<BR> Protected WithEvents Label3 As System.Web.UI.WebControls.Label<BR> Protected WithEvents Label4 As System.Web.UI.WebControls.Label<BR> Protected WithEvents Button1 As System.Web.UI.WebControls.Button<BR> Protected WithEvents TextBox1 As System.Web.UI.WebControls.TextBox<BR> Protected WithEvents TextBox2 As System.Web.UI.WebControls.TextBox<BR> '注意: 以下占位符声明是 Web 窗体设计器所必需的。<BR> '不要删除或移动它。<BR> Private designerPlaceholderDeclaration As System.Object</P>
<P> Private Sub Page_Init(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Init<BR> 'CODEGEN: 此方法调用是 Web 窗体设计器所必需的<BR> '不要使用代码编辑器修改它。<BR> InitializeComponent()<BR> End Sub</P>
<P>#End Region</P>
<P> Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click<BR> strID = Trim(Me.TextBox1.Text)<BR> If strID = "" Then<BR> Me.Label4.Text = "请输入登录的用户名称。"<BR> Exit Sub<BR> End If<BR> pwd = Trim(Me.TextBox2.Text)<BR> sqlstr = "SELECT*FROM userID WHERE" & "(用户名='" & strID & "') "<BR> DS = New DataSet<BR> DS.Clear()<BR> DS = GetDataFromDB(sqlstr)<BR> If DS.Tables(0).Rows.Count > 0 Then<BR> sqlstr = "SELECT*FROM userID WHERE" & "(用户名='" & strID & " ') AND (密码='" & pwd & " ') "<BR> Dim myDS As DataSet<BR> myDS = New DataSet<BR> myDS.Clear()<BR> myDS = GetDataFromDB(sqlstr)<BR> If myDS.Tables(0).Rows.Count > 0 Then<BR> pepdom = myDS.Tables(0).Rows(0)("权限")<BR> Me.Response.Redirect("<a href="http://localhost/EIMS//WebfrmMain.aspx" target="_blank" >http://localhost/EIMS//WebfrmMain.aspx</A>")<BR> Else<BR> Me.Label4.Text = "输入的密码不正确，请重新输入密码。"<BR> Me.TextBox2.Text = ""<BR> End If<BR> Else<BR> Me.Label4.Text = "查无此人，请确认是否有该用户存在。"<BR> Me.TextBox1.Text = ""<BR> Me.TextBox2.Text = ""<BR> End If<BR> End Sub<BR>End Class</P>
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