ADO.NET跟VB6.0、VBA中的ADO变化较大。

在.NET中要使用ADO.NET，首先需要引用System. Data. Ole Db 命名空间。

在ADO.NET中，如果要连接某个数据源可以有多种方法。

方法一、使用Ole DbConnection 类。

比如要连接某个Access数据库文件，可以使用如下的代码段：

Imports ado = System.Data.OleDb
Module Module1
    Sub QQ1722187970()
        Dim sConstr As String
        sConstr = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" & sFile & ";Persist Security Info=False;"
        Dim oCon As New ado.OleDbConnection(sConstr)
        oCon.Open()
    End Sub
End Module

然后要返回查询结果，可以使用Ole DbCommand类，用该类的Execute Reader方法返回一个查询结果集OleDbDataReader类。

代码段如下：

Imports ado = System.Data.OleDb
Module Module1
    Sub QQ1722187970()
        Dim sConstr As String
        sConstr = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" & sFile & ";Persist Security Info=False;"
        Dim oCon As New ado.OleDbConnection(sConstr)
        oCon.Open()
        Dim sSQl As String
        sSQl = "select * from 教师授课表"
        Dim oCmd As New ado.OleDbCommand(sSQl, oCon)
        Dim oReader As ado.OleDbDataReader = oCmd.ExecuteReader()
    End Sub
End Module

最后读取OleDbDataReader，代码如下：

Imports lbForm = System.Windows.Forms
Imports ado = System.Data.OleDb
Public Class Form1
    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        Dim oOpenFileDialog As New lbForm.OpenFileDialog
        Dim sFile As String
        Dim arrFN()
        With oOpenFileDialog
            .ShowDialog()
            sFile = .FileName
            If Len(sFile) Then
                Dim sConstr As String
                sConstr = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" & sFile & ";Persist Security Info=False;"
                Dim oCon As New ado.OleDbConnection(sConstr)
                oCon.Open()
                Dim sSQl As String
                sSQl = "select * from 教师授课表"
                Dim oCmd As New ado.OleDbCommand(sSQl, oCon)
                Dim oReader As ado.OleDbDataReader = oCmd.ExecuteReader()
                Dim iCol As Integer
                With oReader
                    iCol = .FieldCount
                    '读取字段名
                    For I = 0 To iCol - 1
                        Dim sFieldName As String
                        sFieldName = .GetName(I)
                        ReDim Preserve arrFN(I)
                        arrFN(I) = sFieldName
                        Debug.Print(sFieldName)
                    Next
                    '逐条读取记录
                    Do Until .Read = False
                        For I = 0 To iCol - 1
                            Dim sValue As String
                            sValue = .Item(arrFN(I))
                            Debug.Print(sValue)
                        Next I
                    Loop
                    .Close()
                End With
                oCon.Close()
            Else
                MsgBox("你没有选择文件")
            End If
        End With
    End Sub
End Class