problem with Datagrid view control in C#

Hi Im newbie and facing problem in Datagrid in Windows forms with C#. I have a datagrid on the windows form with two textboxes and two comboboxes. When I click a button on the windows form i should read an xml file and populate the datagrid control. Im able to put the values for textboxes but Im unable to put values for the combobox. 
  Because in the code i have kept an enum with the values as of the items in the combox and when I apply Im facing an error. Can anyone tell me how to populate comboxbox in the datagrid. 
        I also tried to populate the controls at runtime.. but failed. Can anyone help me in this.. If you want the code I will provide you.. 


Thanks in advance..