vb.net从数据库取具体值

            Dim conn As New OleDbConnection("Provider=SQLOLEDB.1;Integrated Security=SSPI;Persist Security Info=False;Initial Catalog=student;Data Source=.")  
            str = "select * from news where id=" & id  
            Dim cmd As New OleDbCommand(str, conn)  
            Dim ds As New DataSet()  
            Dim adp As New OleDbDataAdapter(cmd)  
            adp.Fill(ds, "link")  
            Dim dt As New DataTable  
            dt = ds.Tables("link")  
            Dim dr As DataRow  
            dr = dt.Rows(0)  
            Label1.Text = dr("newscontent").ToString  

       Dim conn As OleDbConnection
        conn = New OleDbConnection("Provider=SQLOLEDB.1;Integrated Security=SSPI;Persist Security Info=False;Initial Catalog=hetong;Data Source=.")
        Dim cmdclients As OleDbCommand
        cmdclients = New OleDbCommand("select   *   from  clients  ", conn)
        Dim adpclients As OleDbDataAdapter
        adpclients = New OleDbDataAdapter(cmdclients)
        Dim dsclients As New DataSet
        adpclients.Fill(dsclients, "link")
        Dim dtclients As New DataTable()
        dtclients = dsclients.Tables("link")
        Dim drclients As DataRow
        drclients = dtclients.Rows(i)

• dim dr as new datareader  dr当一个变量使用 只能赋值一次