vb.net 连接sql数据库

Imports System.Data
Imports System.Data.OleDb
Module Module1
Public Function MdbMytab(ByVal str_select As String) As DataTable
Dim conn_mdb As New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0; Data Source=mdb.mdb")
Dim cmd As New OleDbCommand(str_select, conn_mdb)
Dim da As New OleDbDataAdapter(cmd)
Dim mytb As DataSet = New DataSet
da.Fill(mytb, 0)
MdbMytab = mytb.Tables(0)
conn_mdb.Close()
End Function
End Module
以上为模块代码

以下为窗体代码：
Imports System.Data
Imports System.Data.OleDb
Public Class Form1
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

Dim mytb As DataTable = MdbMytab("select * from 表1")
DataGridView1.DataSource = mytb
ComboBox1.DisplayMember = "姓名"
ComboBox1.DataSource = mytb
End Sub
End Class