linq

How do I sign requests reliably for the Last.fm api?

I'm trying to implement authorization through Last.fm. I'm submitting my arguments as a Dictionary to make the signing easier. This is the code I'm using to sign my calls: public static string SignCall(Dictionary<string, string> args) { IOrderedEnumerable<KeyValuePair<string, string>> sortedArgs = args.OrderBy(arg => arg.Key); s...

How to get rank from full-text search query with Linq to SQL?

I am using Linq to SQL to call a stored procedure which runs a full-text search and returns the rank plus a few specific columns from the table Article. The rank column is the rank returned from the SQL function FREETEXTTABLE(). I've added this sproc to the O/R designer with return type Article. This is working to get the columns I ne...

Entity Framework 4 missing features?

I'm well aware that similair topics have been brought up before e.g. http://stackoverflow.com/questions/1639043/entity-framework-4-vs-nhibernate But instead of arguments like: NHibernate have been around longer and is more mature EF4 is drag n drop and not enterprisy EF4 and LinqToSql are ... I would like to see a more detailed lis...

Mutating the expression tree of a predicate to target another type

Intro In the application I 'm currently working on, there are two kinds of each business object: the "ActiveRecord" type, and the "DataContract" type. So for example, we have: namespace ActiveRecord { class Widget { public int Id { get; set; } } } namespace DataContract { class Widget { public int Id { get;...

LINQ Query with 3 levels

I have a business object structured like this: Country has States, State has Cities So Country[2].States[7].Cities[5].Name would be New York Ok, I need to get a list of all the Country objects which have at least 1 City.IsNice == true How do I get that? ...

How do I add a where filter using the original Linq-to-SQL object in the following scenario

I am performing a select query using the following Linq expression: Table<Tbl_Movement> movements = context.Tbl_Movement; var query = from m in movements select new MovementSummary { Id = m.DocketId, Created = m.DateTimeStamp, CreatedBy = m.Tbl_User.FullName, ...

What guarantees are there on the run-time complexity (Big-O) of LINQ methods?

I've recently started using LINQ quite a bit, and I haven't really seen any mention of run-time complexity for any of the LINQ methods. Obviously, there are many factors at play here, so let's restrict the discussion to the plain IEnumerable LINQ-to-Objects provider. Further, let's assume that any Func passed in as a selector / mutator /...

Linq is returning too many results when joined

In my schema I have two database tables. relationships and relationship_memberships. I am attempting to retrieve all the entries from the relationship table that have a specific member in it, thus having to join it with the relationship_memberships table. I have the following method in my business object: public IList<DBMappings....

Using LinqExtender to make OData feed fails

A pretty simple question, has anyone here tried to make a OData feed based on a IQueryable created with LinqExtender? I have created a simple Linq-provider that supports Where, Select, OrderBy and Take and wanted to expose it as an OData Feed. I keep getting an error though, and the Exception is a NullReference with the following StackT...

[LINQ] Nested query problem

I have 3 classes in C#: class Folder { int Id { get; set; } List<File> files { get; set;} } class File { int Id { get; set; } Author author { get; set; } } class Author { int Id { get; set; } string Name { get; set; } } I have a list of Folder items (List): var folders = getAllFolders(); How can I use Lin...

Using LINQ in generic collections

Hi, Please consider the following snippet from an implementation of the Interpreter pattern: public override object Execute(Interpreter interpreter, object ctx) { var list = ctx as IEnumerable<string>; return (list != null) ? list.FirstOrDefault() : null; } What about if I want to use the same function for integers? public o...

How can I do this with LINQ?

All I'm after doing is this: SELECT CallTypeID, Count(CallTypeID) as NumberOfCalls FROM [Helpdesk_HR].[dbo].[CallHeader] WHERE CallHeader.DateOpened <= GETDATE()-7 GROUP BY CallTypeID in LINQ. But I can't work out a way of doing it and getting it to work. I would use Linqer, but my company won't pay for it at present. Any help is gre...

Decrement all int values in Dictionary

I have a Dictionary<string,int> and I simply want to decrement the value in my dictionary by one. I have this but not sure if its best practice. foreach (KeyValuePair<string, int> i in EPCs) { EPCs[i.Key] = i.Value - 1; } UPDATE: The reason I am trying to decrement the value is becase the value is a index number relating to a posi...

LINQ Normalizing data

I am using an OMS that stores up to three line items per record in the database. Below is an example of an order containing five line items. Order Header Order Detail Prod 1 Prod 2 Prod 3 Order Detail Prod 4 Prod 5 One order header record and two detail records. My goal is have a one to one relation for details records(...

Good way to get the key of the highest value of a Dictionary in C#

I'm trying to get the key of the maximum value in the Dictionary<string, double> results. This is what I have so far: double max = results.Max(kvp => kvp.Value); return results.Where(kvp => kvp.Value == max).Select(kvp => kvp.Key).First(); However, since this seems a little inefficient, I was wondering whether there was a better way ...

How to write this query in Linq2Sql

I have a table company which holds the company_id, company_name and other details. I have a table subcontracts which has a company_id column that maps to company.company_id. How can I write a select statement to get all active companies which have not been assigned to an active subcontract? IE The company_id cannot be found in subcont...

Combining 2 Linq queries into 1

Given the following information, how can I combine these 2 linq queries into 1. Having a bit of trouble with the join statement. 'projectDetails' is just a list of ProjectDetails ProjectDetails (1 to many) PCardAuthorizations ProjectDetails (1 to many) ExpenditureDetails Notice I am grouping by the same information and selecting the sa...

How to transform one list to another semi-aggregated list via LINQ?

I'm a Linq beginner so just looking for someone to let me know if following is possible to implement with Linq and if so some pointers how it could be achieved. I want to transform one financial time series list into another where the second series list will be same length or shorter than the first list (usually it will be shorter, i.e....

Simple database design and LINQ

I have very little experience designing databases, and now I want to create a very simple database that does the same thing I have previously had in xml. Here's the xml: <services> <service type="writing"> <small>125</small> <medium>100</medium> <large>60</large> <xlarge>30</xlarge> </service> <service type="analys...

select n largest using LINQ

This is likely a novice question about LINQ, but assuming I have a set of Items with a DateTime property, one date having at most one item, how would I go about selecting the N most recent items from a date of reference, that is, the N items which have a date smaller that the requested date, and the largest date? My naive thought would b...