事件源头:
当用IQueryable查询并用groupby select 时,每次都new object匿名对象,导致在var mEntitys = projectApp.SearchDataAllYear();时mEntitys中data["main"]不可遍历

public Result SearchDataAllYear()
{
            Dictionary<string, List<ProjectDetailEntityExt>> mEntitys = new Dictionary<string, List<ProjectDetailEntityExt>>();
            List<ProjectEntity> mProjectItems = new List<ProjectEntity>();

            var mainlist = detailviewService.IQueryable().Where(p => p.F_DeleteMark == null || p.F_DeleteMark == false)
                .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();

            Result rs = new Result();
            rs.data.Add("main", mainlist);
            return rs;
}

解决方法:定义一个实体类,替代匿名object

//新建实体类
public class mp
{
            public string project_id { get; set; }
            public string projectTitle { get; set; }
            public string projectFullName { get; set; }
            public int projectYear { get; set; }
            public DateTime? projectTime { get; set; }
            public Decimal? total { get; set; }
 }

//改用实体类
public Result SearchDataAllYear2()
 {
            Dictionary<string, List<ProjectDetailEntityExt>> mEntitys = new Dictionary<string, List<ProjectDetailEntityExt>>();
            List<ProjectEntity> mProjectItems = new List<ProjectEntity>();
            var sonlist = detailviewService.IQueryable().Where(p => p.F_DeleteMark == null || p.F_DeleteMark == false)
                     .GroupBy(p => new { p.project_id,p.F_ProjectTitle,p.F_FullName,p.F_ProjectYear,p.F_ProjectTime })
                     .Select(p => new mp()
                     {
                         project_id = p.Key.project_id,
                         projectTitle = p.Key.F_ProjectTitle,
                         projectFullName = p.Key.F_FullName,
                         projectYear = p.Key.F_ProjectYear,
                         projectTime = p.Key.F_ProjectTime,
                         total = p.Sum(w => w.F_ProjectFee)
                     }).ToList();
            Result rs = new Result();
            rs.data.Add("son", sonlist);
            return rs;
 }

此时可以遍历,注意要用IQueryable<T>强制类型转换一下

 var me = projectApp.SearchDataAllYear2();
foreach (var attt in (IQueryable<ProjectApp.mp>)me.data["son"])
{
  var pid = item.project_id;
  var projectTitle = item.projectTitle;
  var projectFullName = item.projectFullName;
  var projectYear = item.projectYear;
  var projectTime = item.projectTime;
  var total = item.total;
}