Question

我有这个查询

public IEnumerable<TimesheetModel> FilterByUserId(IEnumerable<TimesheetModel> obj, int FilterUserId)
{
     var query = (from list in obj.Where(x => x.List.Where(x => x.UserId.Equals(FilterUserId)))
                  select new TimesheetModel
                  {
                      TaskDate = list.TaskDate,
                      List = list.List
                  }).ToList();

     return query;
}

我有错误：

无法在此范围内声明名为“x”的局部变量，因为它会给'x'赋予不同的含义，它已经在a中使用了 “父母或当前”范围表示其他内容。

为什么我有这个错误以及如何解决这个问题？

我有这个模型

public class TimesheetModel
{
    public DateTime TaskDate { get; set; }
    public IEnumerable<TimesheetListModel> List { get; set; }

    public TimesheetModel() { List = new List<TimesheetListModel>(); }
}

并且

public class TimesheetListModel
    {
        public DateTime Date        { get; set; }
        public bool?    InProgress  { get; set; }
        public string   Note        { get; set; }
        public int      ProjectId   { get; set; }
        public string   ProjectName { get; set; }
        public string   Task        { get; set; }
        public decimal? TimeWorked  { get; set; }
        public int?     Type        { get; set; }
        public int      UserId      { get; set; }
        public string   UserName    { get; set; }
        public int?     WorkItemId  { get; set; }

    }

我的任务是通过UserId过滤此模型

{
    "TaskDate": "2015-01-04T00:00:00",
    "List": [
        {
            "WorkItemId":24,
            "ProjectId":3,
            "ProjectName":"Hello world",
            "UserId":12,
            "UserName":"Anatoliy Svetliakov",
            "Date":"2015-01-04T22:00:00",
            "Task":"#34 : New task test",
            "TimeWorked":2,
            "Note":null,
            "InProgress":false
        }
    ]
}

Answer 1

你在两个lambda表达式中使用x作为变量（obj.Where，即父范围＆amp; list.Where，这是当前范围），试试这个：

   public IEnumerable<TimesheetModel> FilterByUserId(IEnumerable<TimesheetModel> obj, int FilterUserId)
    {
         var query = (from list in obj.Where(z=>z.List.Any(u=>u.UserId==FilterUserId))
                      select new TimesheetModel
                      {
                          TaskDate = list.TaskDate,
                          List = list.List.Where(o=> o.UserId.Equals(FilterUserId)).FirstOrDefault()
                      }).ToList();

         return query;
    }

Answer 2

错误信息是自解释的，你需要不同的变量： -

from list in obj.Where(x => x.List.Where(z => z.UserId.Equals(FilterUserId)))

此外，在比较Any时，您的查询应该使用Where而不是UserId： -

 var query = (from list in obj.Where(x => x.List.Any(z => z.UserId.Equals(FilterUserId)))
                  select new TimesheetModel
                  {
                      TaskDate = list.TaskDate,
                      List = list.List
                  }).ToList();

Answer 3

您需要一个不同于x的变量，如下所示：

 var query = (from list in obj.Where(x => x.List.Where(y => y.UserId.Equals(FilterUserId)))
                  select new TimesheetModel
                  {
                      TaskDate = list.TaskDate,
                      List = list.List
                  }).ToList();

Linq参数错误

3 个答案: