示例
var mainlist = detailviewService.IQueryable().Where(p => p.F_DeleteMark == null)
.GroupBy(p => new {p.F_FullName,p.F_ProjectYear})
.Select(p => new
{
p.Key.F_FullName,
p.Key.F_ProjectYear,
total= p.Sum(w=>w.F_ProjectFee)
}).ToList();
