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MongoDB GroupBy Aggregate and Count Documents C#

I have a requirement to get the count of documents based on status of customer. So I need to use aggregate function and then group by based on status. I have used following code for that but the problem is that in Result I am getting the list of documents but what I just want to have is the status and count of documents under that. Can any body please help in adjusting the query to achieve the results.
var result = collection.Aggregate()
.Group(
x => x.status,
g => new
{
Result = g.Select(x => new CustomerDetailsList
{
ActiveType = x.status,
Count = g.Count()
}
)
}
);
Thanks in advance

The reason you're getting a list of documents for every key is that you're running this nested Select, all you need is:
collection.Aggregate()
.Group(
x => x.status,
g => new CustomerDetailsList
{
ActiveType = g.Key,
Count = g.Count()
}).ToList();

I am satisfied with the answer of #mickl and it works well as I tested according to my requirement but here is the way I opted in my app as this is what I am comfortable with. The method is to use the collection as queryable
var result = collection.AsQueryable()
.GroupBy(x => x.status)
.Select(x => new CustomerDetailsList
{
ActiveType = x.Key, Count = x.Count()
}).ToList();
I have used more LINQ in this way so I choose this as it's better to understand for me.
You can choose any of the methods either this or as demonstrated by #mickl

Linq query to select all numbers that match

I have some difficulties to query a table. In the table there are a column for ResourceID and a column for ProjectID. I want to get a list of all int numbers from the ResourceID where ProjectID match the projId number. Is this possible?
I have tested, but I guess this is wrong. I thought I could get the value by using the resources variable, but that isn't working.
var resources = db.Activities.Where(x => x.ProjectID == projId).ToList();
resources. ????

You could accomplish this via a Select() query to only pull the specific properties that you need (in this case the ResourceID property) for each of the elements within your collection :
// Get your resources that meet your requirement
var resources = db.Activities.Where(x => x.ProjectID == projId).ToList();
// Get your Resource IDs from your previous query
var resourceIds = resources.Select(r => r.ResourceID);
You could actually just perform this in a single call if you preferred :
// This will return a list of ResourceIDs that match
var resourceIds = db.Activities.Where(a => a.ProjectID == projId)
.Select(a => a.ResourceID)
.ToList();

I believe the answer is:
var resources = db.Activities.Where(x => x.ProjectID == projId).Select(x => x.ResourceID).ToList();

You're getting a list of the Activities. What you need to do is to select the item you want--in this case the ResourceID column.
var resources = db.Activities.Where(x => x.ProjectID == projId)
.Select(x => x.ResourceID)
.Distinct() // Thought you might want this
.ToList();
You can also use a different format like this, which can sometimes be clearer.
var resources = (from a in db.Activities
where a.ProjectID == projId
select a.ResourceID).Distinct().ToList();

Please update your query if you want to get list of int..
var resources = db.Activities.Where(x => x.ProjectID == projId).Select(x => x.ResourceID).ToList();

Get complex object using IN equivalent in LINQ

I have a list of type customer. I need to insert all values of the list in the database before checking if a customer with the same customer number exists for that particular client.
For that I am firing a query to get me all customers who are there in the database having customer number equal to ones in the list. The query I am writing is not working, here's the code.
CustomerRepository.Find(x => x.ClientId == clientId)
.Where(x => x.CustomerNumber.Contains(lstCustomersInserted.Select(c => c.CustomerNumber)));

Keep it simple:
var lstCustomerNumbers = lstCustomersInserted.Select(c => c.CustomerNumber);
var res = CustomerRepository.Where(x => x.ClientId == clientId && lstCustomerNumbers.Any(c => c == x.CustomerNumber));

I think you have it backwards. Try reversing the Contains.
Edit: I switched to using the generic predicate Exists instead of Contains based on the comment, so you can match a property.
CustomerRepository.Find(x => x.ClientId == clientId)
.Where(x => lstCustomersInserted.Exists(c => x.CustomerNumber == c.CustomerNumber));

How about an Except?
CustomerRepository.Select(x => x.ClientID)
.Except(lstCustomersInserted.Select(x => x.CustomerID));
This will return the IDs of the objects in the repo that don't exist in your lstCustomersInserted.

Returning Most Relevant Search Results Using LINQ Where/Take

I have a List<Locations> that will be filtered to yield a set of results relevant to a search term.
At the moment, I tried these 'search results' by filtering with the following:
return locations.Where(o => o.Name.Contains(term)).Take(10).ToList();
Problem
If I were to enter 'Chester' as the search term, I will never see the item "Chester" despite it existing in the locations list. The reason for this is that there are 10 or more other items in the list that contain the String "Chester" in their name (Manchester, Dorchester etc.).
How can I use LINQ to first of all take the results that start with the search term?
What I've Got So Far
var startsWithList = list.Where(o => o.Name.StartsWith(term)).Take(10).ToList();
var containsList = list.Where(o => o.Name.StartsWith(term) && !startsWithList.Contains(o)).Take(10 - startsWithList.Count).ToList();
return startsWithList.AddRange(containsList);
I don't like the above code at all. I feel like this should be achieved in one Where as opposed to performing two Where and Take's and combining the two lists.

just order ascending before Take, putting a lower value for items starting with term.
return locations.Where(o => o.Name.Contains(term))
.OrderBy(m => m.Name.StartsWith(term) ? 0 : 1)
//or OrderByDescending(m => m.Name.StartsWith(term))
.Take(10)
.ToList();
adapted with the improvement of MikeT (exact match before StartsWith), you could just do
return locations.Where(o => o.Name.Contains(term))
.OrderBy(m => m.Name.StartsWith(term)
? (m.Name == term ? 0 : 1)
: 2)
.Take(10)
.ToList();

I have created a new github project that uses expression trees to search for text in any number of properties
It also has a RankedSearch() method which returns the matching items with the number of hits for each record meaning you can do the following:
return locations.RankedSearch(term, l => l.Name)
.OrderByDescending(x => x.Hits)
.Take(10)
.ToList();
If you wanted you could search accross multiple properties
return locations.RankedSearch(term, l => l.Name, l => l.City)
... or for multiple terms,
return locations.RankedSearch(l => l.Name, term, "AnotherTerm" )
... or for both multiple properties and multiple terms
return locations.RankedSearch(new[]{term, "AnotherTerm"},
l => l.Name,
l => l.City)
Checkout this post for more information on the SQL generated and other usages:
http://jnye.co/Posts/27/searchextensions-multiple-property-search-support-with-ranking-in-c-sharp
You can download this as a nuget package to:
https://www.nuget.org/packages/NinjaNye.SearchExtensions/

Raphaël's Solution will work but if you were say searching for Warwick you could find that it might not put Warwick the top of the list if Warwickshire is also a possible location,using the scores you can also extend this infinitely with more matching methods, as well as tweaking the score values to refine your search order
return locations.Select(l => New {SearchResult=l,
Score=(L.Name == Term ?
100 :
l.Name.StartsWith(term) ?
10 :
l.Name.Contains(term) ?
1 :
0
)})
.OrderByDescending(r=>r.Score)
.Take(10)
.Select(r => r.SearchResult);
note i would probably do this by making a Match method and do the logic in there rather than in the linq like i did above so it would just be
return locations.OrderByDescending(Match).Take(10);

All Solutions will work but the better score can gain more easier as below
return locations.Where(o => o.Name.Contains(term))
.OrderBy(m => m.Name.IndexOf(term))
.Take(10)
.ToList();
as a result each name that contain term at nearest to start, show first.

What about this?
return locations.Where(o => o.Name.Contains(term))
.OrderBy(m => m.Length)
.Take(10)
.ToList();

Order By on the Basis of Integer present in string

I've a problem in my C# application... I've some school classes in database for example 8-B, 9-A, 10-C, 11-C and so on .... when I use order by clause to sort them, the string comparison gives results as
10-C
11-C
8-B
9-A
but I want integer sorting on the basis of first integer present in string...
i.e.
8-B
9-A
10-C
11-C
hope you'll understand...
I've tried this but it throws exception
var query = cx.Classes.Select(x=>x.Name)
.OrderBy( x=> new string(x.TakeWhile(char.IsDigit).ToArray()));
Please help me... want ordering on the basis of classes ....

Maybe Split will do?
.OrderBy(x => Convert.ToInt32(x.Split('-')[0]))
.ThenBy(x => x.Split('-')[1])

If the input is well-formed enough, this would do:
var maxLen = cx.Classes.Max(x => x.Name.Length);
var query = cx.Classes.Select(x => x.Name).OrderBy(x => x.PadLeft(maxLen));

You can add 0 as left padding for a specified length as your data for example 6
.OrderBy(x => x.PadLeft(6, '0'))

This is fundamentally the same approach as Andrius's answer, written out more explicitly:
var names = new[] { "10-C", "8-B", "9-A", "11-C" };
var sortedNames =
(from name in names
let parts = name.Split('-')
select new {
fullName = name,
number = Convert.ToInt32(parts[0]),
letter = parts[1]
})
.OrderBy(x => x.number)
.ThenBy(x => x.letter)
.Select(x => x.fullName);
It's my naive assumption that this would be more efficient because the Split is only processed once in the initial select rather than in both OrderBy and ThenBy, but for all I know the extra "layers" of LINQ may outweigh any gains from that.