vb.net数据库连接问题

[tingyst]

本人菜鸟，求助！
我要将vb.net与access数据库相连接，代码如下：

Private Con As String = "Provider=Microsoft.Jet.OLEDB.4.0; Data Source=d:\db1.mdb; "
Private connconnection As System.Data.OleDb.OleDbConnection
Private conncommand As OleDb.OleDbCommand


Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
Dim conn As New OleDb.OleDbConnection

Dim sql As String = "insert into data (id,shijian,neirong,riqi) values('" + TextBox2.Text + "','" + TextBox3.Text + "','" + TextBox4.Text + "','" + TextBox5.Text + "')"

Dim cmd = New OleDb.OleDbCommand(sql, conn)
cmd.CommandType = CommandType.TableDirect


Try
conn.Open()
cmd.ExecuteNonQuery()
MsgBox("ok! ")
Catch ex As Exception
MsgBox("failed! " & ex.ToString())
Finally
conn.Close()
End Try



End Sub



运行后提示：