Select an object based on the condition in nested array(LINQ ,MongoDB)

Question

{
"Id": 1234,
"CommentType": "project",
"EntityReferenceId": "1345-154-154",
"Members": [{
    "MemberId": "1354",
    "Name": "a",
    "Email": "[email protected]"
}],
"Threads": [{
        "Id": "233",
        "UserReferenceId": "32343",
        "UserName": "433434",
        "CommentByUserType": "Agent",
        "Content": "dfdfdsfs sfdf sdf",
        "PostedDate": "0001-01-01T00:00:00",
        "Active": true,
        "Attachment": [{
            "AttachmentName": "ad",
            "AttachmentUrl": "http://fdf.jpg"
        }]
    },
    {
        "Id": "233",
        "UserReferenceId": "32343",
        "UserName": "433434",
        "CommentByUserType": "Agent",
        "Content": "dfdfdsfs sfdf sdf",
        "PostedDate": "0001-01-01T00:00:00",
        "Active": false,
        "Attachment": [{
            "AttachmentName": "ad",
            "AttachmentUrl": "http://fdf.jpg"
        }]
    }]
}

I am using MongoDb to linq, This is my Comment" object format.for each Project there is a comment object.Each Comment object contains a list of "Threads"(you can see this above example).I want to load the "Comment" object with all thread which is Active("Active": true)

var result = _context.Comments
                     .AsQueryable()
                     .Where(x => x.EntityReferenceId == EntityReferenceId &&
                                 x.CommentType == Type && 
                                 x.Threads.Any(z=>z.Active==true))
                     .FirstOrDefault();

I used this query but it loading all threads if Any thread have "Active" value is true.

 x.Threads.Any(z=>z.Active==true)

returns only bool values.I need a solution please

Have you tried to replace Any with Where and see the result? — Salah Akbari
– Salah Akbari, Commented Mar 13, 2018 at 5:14
I think we cant use "Where".Operator && cannot be applied to operands of type bool and IEnumerable<Threads> — Ajas Aju
– Ajas Aju, Commented Mar 13, 2018 at 5:18
That condition will not work cause you getting a master object based on child condition and master object contain multiple child you are not filtering child. — Umair Anwaar
– Umair Anwaar, Commented Mar 13, 2018 at 7:18

D-Shih · Accepted Answer · 2018-03-13 05:48:35Z

2

You can use x.Threads.Any(z=>z.Active==true) be where condition. or you will judge Threads collection is contain Active==true data.

A simple way you can do like this.

var result = _context.Comments
         .AsQueryable()
         .Where(x => x.EntityReferenceId == EntityReferenceId &&
                     x.CommentType == Type)
         .FirstOrDefault();

if (result!=null)
{
    result1.Threads = result1.Threads.Where(z => z.Active == true);
}

Or

use select method

var result = _context.Comments
                     .AsQueryable()
                     .Where(x => x.EntityReferenceId == EntityReferenceId &&
                                 x.CommentType == Type)
                     .Select(o => new Comment{
                        Id = o.Id,
                        Members = o.Members,
                        EntityReferenceId = o.EntityReferenceId,
                        CommentType = o.CommentType,
                        Threads = o.Threads.Where(z => z.Active == true)
                     })
                     .FirstOrDefault();

edited Mar 13, 2018 at 5:48

answered Mar 13, 2018 at 5:40

D-Shih

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2 Comments

Ajas Aju Over a year ago

I think this is not a proper way,why because,in the first query it will take the whole threads even if it is not active.if there is big amount of inactive comments it will also load.by cause of this it will be slow.

Ajas Aju Over a year ago

But this Downcasting is not supported ,I am using mongoDb database

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