c# - 无法在 C# 中隐式转换类型 'System.Collections.Generic.List

Question

您好，我是编程新手，您能帮我解决这个问题吗:

我在“To.List()”中遇到错误 错误 1 ​​无法将类型“System.Collections.Generic.List”隐式转换为“System.Collections.Generic.List”

我的代码是:

List<IncByYrMonthModel> GroupedList = (from p in incidentsViewModel
                                       group p by new 
                                       { 
                                           month = p.DateClosed.Value.Month, 
                                           year = p.DateClosed.Value.Year 
                                       } into d
                                       select new 
                                       {
                                           d.Key.month, 
                                           d.Key.year, 
                                           count = d.Count() 
                                        }).ToList();
return GroupedList;

我的模型是:

public class IncByYrMonthModel
{
    public string Year { get; set; }
    public string Month { get; set; }
    public string Total { get; set; }
}

更新了代码

public List<IncByYrMonthModel> GetYrMonth2(HttpSessionStateBase session, int id, int _StrYear)
{
    List<IncidentsModel> incidentsViewModel = ViewModelService.Fetch<List<IncidentsModel>>(session, id);

    List<IncByYrMonthModel> GroupedList = (from p in incidentsViewModel
                                           group p by new 
                                           { 
                                               month = p.DateClosed.Value.Month, 
                                               year = p.DateClosed.Value.Year 
                                            } into d
                                            select new IncByYrMonthModel 
                                            { 
                                                Month = d.Key.month, 
                                                Year = d.Key.year, 
                                                Total = d.Count() 
                                            });

        return GroupedList;
    }

Answer 1

你应该改变这个

select new { d.Key.month, d.Key.year, count = d.Count() }

到此

select new IncByYrMonthModel { Month = d.Key.month, Year = d.Key.year, Total = d.Count() }

第一种情况的问题是您有一个匿名类型的对象序列，您尝试将它们转换为 IncByYrMonthModel 列表，这是不可能的。