Dim Cod As Integer
Dim SQL As String
Private Sub combobox_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles combobox.SelectedIndexChanged
Cod = Microsoft.VisualBasic.Compatibility.VB6.GetItemData(combobox, combobox.SelectedIndex)
SQL = "select idalumno,codigo,nombre,sexo from Alumno where codigo=" & Cod
Com = New SqlCommand(SQL, MiConexion)
Rs = Com.ExecuteReader()
Rs.Read()
txtAlumno.Text = Rs(0).ToString 'idalumno
txtNombre.Text = Rs(1).ToString 'Nombre
....
....
....
Rs.Close()
End Sub