Deleteing Selected infor from datagrid binded on relationship

hi all,

 i want to delete a row from the datagrid which is binded on the relationship of parent table.
i have a combox filled with dates and datagrid which shows the related information on on the selected date from the combobox when i delete a particular row from datagrid based on any relationship(apart from the first relationship), corresponding row based on the first relationship gets deleted instead of the specified one.

i want 2 delete the selected row from the datagrid could some one help me out on this. If i am not clear, do let me know and i will try to explain.