C# LINQ 判断记录重复

//表格数据源
var listSource = gvSummary.GetDataSource<dt_PaperType>();

//统计重复次数>1的记录
var list = (from s in listSource
             .Where(w => !String.IsNullOrWhiteSpace(w.PaperName))
             .GroupBy(g => g.PaperName)//需要判断是否重复的字段名称
             select new
             {
                 Key = s.Key,
                 RowCount = s.Count() //重复次数
             } into w
             where w.RowCount > 1
             select w).ToList();

if (list.Count > 0)
{
    Msg.Warning(list.FirstOrDefault().Key + " 纸质重复！");
    return false;
}