I Want to add my data to the existing datagridview as new columns in c#

i have following code in c# windows application, as
on form_load()
string str="select * fromlanguages list where languagename='english';
sqlcommand cmd=new sqlcommand(str,con);
sqldataadapter adp =new sqldataadapter(cmd);
datatable dt=new datatable();
adp.fill(dt);
if (dt.rows.count>0)
{
dgv.datasource=dt;
}


now in selectindexchanged of checkedlistbox , i will select another language,
whichever language is selected, that must be displayed beside the english language without refreshing the english data.extra columns are to added.

this i need, any help if helping me with the code.

no it did not help me