同一页面,不同用户控件间的控制

 Rhombus2.CO.Control.COItemBaseInfo  ContrItemBaseInfo = (Rhombus2.CO.Control.COItemBaseInfo)this.Parent.FindControl("COItemBaseInfo1");
if(  ContrItemBaseInfo != null )
{
    if ( ContrItemBaseInfo.ddl_shipto.SelectedValue != "Select" )
    {
        ......
    }
    else
    {
        Response.Write("<script>alert('Please Select the Ship To No First')</script>");//added by libo 20061218   
    }
}