c# - datatable turns empty when i pass it to method -

so have simple function goes through table , find rows has age columns between 2 numbers , return new table new rows. here function :

    private datatable agefinder(int miniage, int maxiage, datatable x)     {         //afwt : analyze table          int count;         datatable dtage = new datatable();         dtage = x.clone();         int agemin = miniage;         int agemax = maxiage;         if (agemin > agemax)         {             int temp = agemax;             agemax = agemin;             agemin = temp;         }         int agedr;          count = 0;         agedr = 0;         datagridview1.datasource = x;         foreach (datarow dr in x.rows)         {             agedr = convert.toint16(x.rows[count]["age "]);             if (agedr >= agemin && agedr < agemax)             {                 dtage.rows.add(dr.itemarray);             }             count++;         }         lblcountthisquery.text = dtage.rows.count.tostring();         return dtage;     } 

and here how call it:

    dtage = agefinder(convert.toint16(tbxminage.text), convert.toint16(tbxmaxage.text), at);     datagridview1.datasource = dtage; 

now can see @ not empty when check x (the table inside method), empty! why happen?