Imports System.Data
Imports System.Data.SqlClient
Public Class Class1
    Dim cn As New SqlConnection("Data Source=.;Initial Catalog=bdprueba;Integrated Security=SSPI")

    Public Sub actualiza(ByVal sql$)
        If cn.State = ConnectionState.Closed Then
            cn.Open()
        End If
        Dim Cmd As New SqlCommand(sql, cn)
        Cmd.ExecuteNonQuery()
        cn.Close()
    End Sub
End Class
  

<a href='actualizaalumno.aspx?id=<%#Eval("cod")%>'> 
</a>
  

Imports System.Data.SqlClient
Public Class actualizaalumno_aspx
    Inherits System.Web.UI.Page
    Dim og As New claseproductos.Class1
    Dim Dr As SqlDataReader


    Dim cn As New SqlConnection("Data Source=.;Initial Catalog=bdprueba;Integrated Security=SSPI")
    Dim cmd As SqlCommand

    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
      
  Session("codig") = Request.Item("id")   'aqui estoy recibiendo el dato enviado 


        Dr = og.leereader("sp_listaAlumno '" & Session("codi") & "'")
        Dr.Read()
        txt1.Text = Dr(0)
        txt2.Text = Dr(1)
        txt3.Text = Dr(2)
   
        Dr.Close()

   End Sub
  

 try  
 og.actualiza("sp_actualizaAlumno '" & Session("codi") & "','" &
                        txt2.Text & "','" & txt3.Text & "'")
            Response.Redirect("Alumno.aspx")
Catch ex As Exception
            MsgBox(ex.Message)
        End Try