Code to get the no of records selected in a grid in infolog 

void clicked()
{
    //this helps us to get the no of records selected in an infolog
    FormDataSource        fds;
    Common                    common;
    int                               counter;
    ;
    super();

    fdS = Table6_DS;//tablename_ds
    for (common = fdS.getFirst(true) ? fdS.getFirst(true) : Table6_DS.cursor(); common; common =     fdS.getNext())
    {
        counter++;
    }
    info(int2str(counter)); 

}