I did my drop down list that get it,s values from database and when run the application it didnot work and compiler didnot see the code

onselectedindexchanged="DDlProductFamily_SelectedIndexChanged">

protected void DDlProductFamily_SelectedIndexChanged(object sender, EventArgs e) {

    using (SqlConnection Con = Connection.GetConnection())
    {

        SqlCommand Com = new SqlCommand("SelectThumbByProductFamily", Con);
        Com.CommandType = CommandType.StoredProcedure;
        Com.Parameters.Add(Parameter.NewInt("@ProductCategory_Id", DDlProductFamily.SelectedValue.ToString()));
        SqlDataAdapter DA = new SqlDataAdapter(Com);
        DA.Fill(dt);
        DataList1.DataSource = dt;
        DataList1.DataBind();
    }
}