Obtener filas distintas de un DataTable

protected DataTable DistinctRows(DataTable dt, string keyfield )
{
DataTable newTable= dt.Clone();
int keyval=0;
DataView dv = dt.DefaultView;
dv.Sort = keyfield;
if( dt.Rows.Count > 0)
{
foreach(DataRow dr1 in dt.Rows)
{
bool existe = false;
foreach (DataRow dr2 in newTable.Rows)
{
if (dr1[keyfield].ToString() == dr2[keyfield].ToString())
existe = true;
}

if(!existe)
{
newTable.ImportRow(dr1);
}
}
}
else
newTable = dt.Clone();
return newTable;
}