Using a Datatable as a data source for a CheckBoxList

I am displaying a check box list of groups, if someone wants to belong to a group they just check the box from the list, I would like to have the list show the current persons groups so when they go to the page all available groups display and the groups they currently belong to are checked.

the data is coming from the groups table (groupid and GroupDescription) and the UsersGroups table (UserId and GroupId)
I am thinking of using 2 datatables groups and userGroups set group as the Datasource to the control and then do for each item in userGroups datatable for each checkboxItem check the items.


Then on the update button(submit) compare again and if item is now unselected I have to delete it from the userGroup table and if new selection i have to add it to the userGroup table
this doesnt seem like the best way of doing this does anyone have any recomendation or ideas?

Thanks



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