如何访问列表 <KeyValuePair<string,int> &gt;来自MongoDB

Question

I am storing in MongoDB records with the following definition:

public class StorageRecord
{
    public int GrId { get; set; }
    public List<KeyValuePair<string,int>> Data { get; set; }
}

and sample like this one below:

var storageRecord = new StorageRecord
{
GrId = 12,
Data = new List<KeyValuePair<string, int>>()
    {
        new KeyValuePair<string, int>("xx", 12),
        new KeyValuePair<string, int>("yy", 13),
        new KeyValuePair<string, int>("zz", 14)
    }
}

Please tell me how should I write the query to retrive the Sum of all of the records which has for example xx key in the Data list of KeyValuePair .

I have started with the following statement but don't know what should be next:

var TotalXX = collection
            .Where(r => r.GrId == grId)
            .GroupBy(t => t.GrId)
            .Select(v => v.Select(c => c.Data));

Answer 1

I think you don't need the GroupBy :

var TotalXX = collection
   .Where(storage => storage.GrId == grId)
   .Sum(storage => storage.Data.Count(kv => kv.Key == "xx"));