how to transfor one datagrid values to another datagrid?

hi,
 i am taking two datagrids in first datagrid contain checkboxes for all columns if user click that checkbox that selected row is display in another datagrid, i do this but my problem is when i select another row (or) multiple rows previous rows of datagrid2 is overrides, means it only display last selected row.
                     i am retrive data from database using id column of datagrid1, that values are  displayed in datagrid2.
every time i select multiple checkboxes that values are fill in dataset and come to new value first value override.
i write datagrid1.datasource=ds.tables[0];
datagrid1.databind();
here datagrid bind last selected value of the first datagrid. but my aim is user selected checkboxes rows all are displayed in datagrid2.
please give a solution of  todo this.
Thanks.