Groupby Linq Error in .Net framework 3.1

Question

I am struggling to convert a linq expression from .Net framework 2.1 into 3.1. Linq Expression is not working when I add subs = g.select...

public JsonResult GetDepotDepartemntsForMap()  
 {  
    dynamic mappingList = new List<DepotMapModel>();  
            mappingList = _unitOfWork.Department.GetDepotWithDepartment();           
            return Json(mappingList);  
 }  
    public dynamic GetDepotWithDepartment()  
            {  
                var list = goContext.goDepartmentWorkTime.  
                    GroupBy(d => new { d.DepotNo, d.Depot.DepotName })  
                .Select(g => new  
                {  
                    id = g.Key.DepotNo,  
                    title = g.Key.DepotName,  
                    subs = g.Select(dd => new  
                    {  
                        id = dd.DepotNo + "." + dd.DepartmentID,  
                        title = dd.Depot.DepotNo + "." + dd.Department.DepartmentName  
                    }).ToList()  
                }).ToList();  
                  
                return list;  
            }  

I have attached herewith my model class in a text file herewith
105481-mapping-depot.txt

Answer 1

Hi PolachanPaily-2805,
First, client side GroupBy is not supported in .netcore 3.1.
You need to grab the data first and processed later with this LINQ query.
So you can change your query as below:

var t=goContext.goDepartmentWorkTime.Include(x=>x.Depot).Include(x=>x.Department).ToList().GroupBy(d => new { d.DepotNo, d.Depot.DepotName })  
            .Select(g => new  
            {  
                id = g.Key.DepotNo,  
                title = g.Key.DepotName,  
                subs = g.Select(dd => new  
                {  
                    id = dd.DepotNo + "." + dd.DepartmentID,  
                    title = dd.Depot.DepotNo + "." + dd.Department.DepartmentName  
                }).ToList()  
            }).ToList();  

You can also try to use AsEnumerable(), more details please refer to this thread.
Best Regards,
Daniel Zhang

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