Get list of DataField in gridview

String boundFields = String.Empty;

for (int i = 0; i < grd.Columns.Count; i++)
{
    DataControlField field = grd.Columns[i];
    BoundField bfield = field as BoundField;

    if (bfield != null)
        boundFields += bfield.DataField + ",";
}
boundFields = boundFields.TrimEnd(','); 

The code is from the following link:

http://stackoverflow.com/questions/6449832/get-list-of-datafield-in-gridview