Populate SPFieldUrl in ItemAdding event

Hi,

I'm having difficulty populating a url field during the item adding event.

Iv'e used the same code to populate a text field so it is just the issue with assigning the values to the URL and Description properties of the field.

//I have a string filename and string URL which have values


SPFieldUrlValue fileLink = new SPFieldUrlValue();
fileLink.Description = filename;
fileLink.URL = URL;
properties.AferProperties["testColumn"] = filelink.

this does not error but doesn't set the testColumn value.

Please advise, thanks