Dim MyDataSet As New DataSet
        Dim Conn As String = "provider=Microsoft.jet.oledb.4.0;data source     =login.mdb"
        Dim MyConn As New OleDb.OleDbConnection
        Dim MyDAO As New OleDb.OleDbDataAdapter
        MyDAO.TableMappings.Add("Table", "user")
        Dim MyCommand As OleDb.OleDbCommand
        MyCommand = New OleDb.OleDbCommand("SELECT * FROM userID WHERE 用户名='" & TxtUserName.Text & "'", MyConn)
        MyCommand.CommandType = CommandType.Text
        MyDAO.SelectCommand = MyCommand

        If MyConn.State <> ConnectionState.Open Then
            MyConn.ConnectionString = Conn
            MyConn.Open()
        End If

        MyCommand.ExecuteNonQuery()

        If MyConn.State <> ConnectionState.Closed Then
            MyConn.Close()
        End If

        MyDAO.Fill(MyDataSet)

        If MyDataSet.Tables("user").Rows.Count = 0 Then
            MsgBox("输入用户名或密码有误，请重试", MsgBoxStyle.Exclamation, Me.Text)
            Exit Sub
        End If

        If MyDataSet.Tables("User").Rows(0)("密码").ToString = TxtUserPassword.Text Then
            MsgBox("登录成功")
        Else
            MsgBox("输入用户名或密码有误，请重试", MsgBoxStyle.Critical, Me.Text)
            Exit Sub
        End If
        Me.Close()