Lost with datatable/datagrid...

Hi!!!

I've been working on this project for some time now. My program can add, save and delete records already. I used a datatable for adding details to new records and it's working just fine. Now I bind my datagrid to this datatable to display the details of the record while adding new items. Now, my problem is how can I refresh my datagrid/datatable when I want to add a new record? Cause when I click on the button that calls on the datatable to fill my datagrid an error appears telling that the column is already a member of the datable. Now I'm also confused between datagrid and datatable! :( Please help! I badly need it!