Can not add/modify dropdown liat after datasource has been loaded

[Guest]

Hi,

In my dropdown I bind to a datasource. After that I try to do one of the
following:
1. Add an Item to the dropdown using dd.Items.Add(newe ListItem("textstr"));
2. Change the text of an existing item in the dropdown. For this one I use
the
followingubDD.Items[pubDD.Items.IndexOf(pubDD.Items.FindByText("textstr"))].Text=otherText;

Neither one works.

Thanks for any suggestions