SharePoint MultipleLookupField Control

Hi, 

I am trying to initialise a multiplelookupfield control from the code behind, but it is not updating. If I declare it on the page with all the parameters it works but it is blank if I do the same thing in code. 

    <div>
        Test 2
        <SharePoint:MultipleLookupField ID="MultipleLookupField2"  ControlMode="Edit" runat="server"></SharePoint:MultipleLookupField>
    </div>
    <div>
        Test 2
        <SharePoint:MultipleLookupField ID="MultipleLookupField3" ListId="68B4FA77-CC06-44B2-8893-68D0DB5183B3" ItemId="4" FieldName="Attendees" ControlMode="Edit" runat="server"></SharePoint:MultipleLookupField>
    </div>

If I set the multiplelookupfield2 in the page load event nothing appears. But when set in the markup it works. Any help would be really appreciated. I am new to Sharepoint and honestly I have forgotten all the asp.net controls. I don't know where I am going wrong. 

        private void SetControlValues(SPListItem item)
        {

            MultipleLookupField1.ListId = new Guid("68B4FA77-CC06-44B2-8893-68D0DB5183B3");
            MultipleLookupField1.ItemId = 4;
            MultipleLookupField1.FieldName = "Attendees";
            MultipleLookupField1.UpdateFieldValueInItem();

}