C#对DataTable中的某列进行分组

IEnumerable<IGrouping<string, DataRow>> result = dt.Rows.Cast<DataRow>().GroupBy<DataRow, string>(dr => dr["FORMSERIALNUMBER"].ToString());//C# 对DataTable中的某列分组，result中的Key是分组后的值
                foreach (IGrouping<string, DataRow> ig in result)
                {                
                    var tmpEmailString = "";
                    foreach (DataRow dr in ig)
                    {
                       string tmpstr = dr[0].ToString() ;                       
                    }
                 
                }