how to assign a datatable column values to s string object.

IList<string> result = new List<string>();
datatable dt=new datatable() ----Contains two column as result.
I need to assign the 2nd column values to the result object.
so i tried this,
result.Add(dt.rows.columns["secondColumn"].tostring());
 but i am getting error.
Is the way ios correcct?
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