c# - 使用 linq 选择字典列表

Question

我对 C# 字典有疑问。我想检索列表以使用

ErrDict.Where(x => x.Key == kurumVKN).Select(x => x.Value) as List<ErrorModel>;

但它返回 null。我怎样才能得到字典的列表？

Dictionary<string,List<ErrorModel> ErrDict = new Dictionary<string,List<ErrorModel>();
 if (ErrDict == null)
     {
       ErrDict = new Dictionary<string, List<ErrorModel>>(); 
     }

List<ErrorModel> listErrModel = ErrDict.Where(x => x.Key == kurumVKN).Select(x => x.Value) as List<ErrorModel>;
 if (listErrModel == null)
     {
        listErrModel=new List<ErrorModel>();
     }
        listErrModel.Add(errModel);
        ErrDict.Remove(kurumVKN);
        ErrDict.Add(kurumVKN, listErrModel);

Answer 1

您需要调用ToList在 Select 之后和 SelectMany展平返回 List<ErrorModel> 列表的查询.试试这个:

var list = ErrDict.Where(x => x.Key == kurumVKN)
           .Select(x => x.Value)
           .SelectMany(x => x) // we add this to get only a single List<ErrorModel>
           .ToList();