Enlazar un Combobox con otro Combobox

[DavidNovato]

Codigo en el LOAD:

Código vb:

Private Sub Form2_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
 
        Dim dt As New DataTable
        Dim conexion As New MySqlConnection("Server=localhost; Database=controlsmi; user=root; password=Smi2012") 'cadena conexion
        Dim SelectedValue As String = "SELECT  ID_producto, nombre FROM producto" 'consulta a la tabla
        Dim comando As New MySqlCommand(SelectedValue, conexion)
        Dim adap As New MySqlDataAdapter(comando)
        conexion.Open()
        adap.Fill(dt)
        conexion.Close()
        cboproducto.DataSource = dt
        cboproducto.DisplayMember = "nombre"
        cboproducto.ValueMember = "ID_producto"
        cboproducto.SelectedIndex = -1
 

Codigo en el EVENTO:

Código vb:

Dim dt As New DataTable
        Dim conexion As New MySqlConnection("Server=localhost; Database=controlsmi; user=root; password=Smi2012") 'cadena conexion 
        Dim SelectedValue As String = "SELECT  serial FROM producto where Id_producto=" + cboproducto.SelectedValue.ToString  'consulta a la tabla"
        Dim comando As New MySqlCommand(SelectedValue, conexion)
        Dim adap As New MySqlDataAdapter(comando)
        conexion.Open()
        adap.Fill(dt)
        conexion.Close()
        cboserial.DataSource = dt
        cboserial.DisplayMember = "serial"
        cboserial.ValueMember = "serial"