ooooooooooooops
there is amistake

Code:
sqlconnection  con=new sqlconnection();
con.connectionstring="data source=server; initial catalog=db;user id=sa";
con.open();
sqlcommand cmd=new sqlcommand("select * from table1",con);
dataset sd=new dataset("table1");
sqldataadapter da=new sqldataadapter(cmd);
da.fill(sd,"tbl_store");
da.fillSchema(sd,schematype.source,"tbl_store");
datagrid dg=new datagrid();
dg.datasource=ds.Tables["tbl_store"];
da.update(ds,"tbl_store");
con.close();
it will work

dataset name recommended not to be same as table name
to update you must get the schema from data adapter