Language Integrated Query (LINQ) is a Microsoft .NET Framework component that adds native data querying capabilities to .NET languages, although ports exist for Java, PHP, JavaScript and ActionScript.
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Good design pattern for linq to sql
I currently have a linq to sql project that was used for one project and not much work was put into it, only the generated context and entities were used. Since then the project has started to become ...
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1answer
69 views
More appropriate to validate a dependency filter parameter by mock+stub or by expression compile?
My lead is enforcing TDD on our project. He says he's following Uncle Bob (Robert Martin) and SOLID principles. One of the rules he's reinforcing is what I call "the single cog rule"--there should be ...
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0answers
4 views
Using Take() with bindingsource [migrated]
How to use Take() with the following code?
var context = new Entities();
BindingSource bi = new BindingSource();
var TableName = cboSelectTable.Text.ToString();
bi.DataSource = ...
0
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1answer
132 views
Why does Linq to Entity Sum return null when the result set is empty?
There are quite a few questions on Stack Overflow about the Linq to Entity / Linq to SQL Sum extension method, about how it returns null when the result set is empty: 1, 2, 3, 4, 5, 6, 7, and many ...
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vote
1answer
215 views
There's a most performant way to check that a collection has exactly 1 element?
I came up with this solution :
if (Take(2).Count() == 1)
is there any more performance solution (or better syntactical sugar) to do this check ?
I want a performance way because this will be an ...
1
vote
2answers
205 views
Is it faster to query using linq-to-entities or a data adapter?
I'm creating an MVC application in VS2012 and I reverse-engineered the models from existing Oracle tables. The tables are part of a MASSIVE database. Besides the main tables that I need to insert, ...
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1answer
123 views
Simplifying data search using .NET
An example on the asp.net site has an example of using Linq to create a search feature on a Music album site using MVC. The code looks like this -
public ActionResult Index(string movieGenre, string ...
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2answers
636 views
foreach in list or foreach in list.where [duplicate]
I don't know what to call this question.
This is my example:
foreach (var item in lstItem.Where(item => stock.ItemCode == item.ItemCode))
{
stock.ItemName = item.ItemName;
...
0
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1answer
71 views
Preference to see if a field's value was changed js or linq object?
We have some requirements to send emails when various field values are changed in our system.
It's an asp.net system using linq to sql with javascript/jquery.
Is it preferred to check if a value ...
1
vote
2answers
177 views
TDD - Making assertions about C# Expression trees
How would you unit test the PerformUpdate method in the sample below? This is a (very) simplified version of some code that performs updates against a database where the schema is dynamic and ...
2
votes
3answers
705 views
Optimal way to implement this specific lookup table in C#?
I want to create a lookup table for this data:
The "input variables" (what is used to "lookup") are 4 different doubles that can each take on 1 of 200 numbers (the numbers range from 1-1000 but there ...
3
votes
1answer
359 views
which sorting algorithms is using OrderBy
I am litle curious about what sorting algorithm is using OrderBy (linq to objects). quicksort? heapsort? introspective sort ?
As i see in MSDN documentation List.Sort is using introspective sort:
...
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1answer
137 views
C# LinqExtensions implement multiple inheritance
According to WikiPedia
"Some languages do not support mixins on the language level, but can easily mimic them by copying methods from one object to another at runtime, thereby "borrowing" the mixin's ...
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votes
3answers
760 views
Is it possible to implement an infinite IEnumerable without using yield with only C# code?
Motivation
The main idea is to explore and understand the limits of how far one can go with the basic LINQ primitives (Select, SelectMany, Concat, etc.). These primitives can all be considered ...
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4answers
1k views
Is linq more efficient than it appears on the surface?
If I write something like this:
var things = mythings
.Where(x => x.IsSomeValue)
.Where(y => y.IsSomeOtherValue)
Is this the same as:
var results1 = new List<Thing>();
...
3
votes
1answer
378 views
Using Dynamic LINQ to get a filter for my Web API
We are considering using the Dynamic.CS linq-sample included in the "Samples" directory of visual studio 2008 for our WebAPI project to allow clients to query our data.
The interface would be ...
3
votes
2answers
346 views
Extracting lambda expressions from linq queries and readability
Every now and then when I have a complex lambda, I do something like this:
Func<SomeObject, bool> equals = o =>
o.ID == someID && o.Name == someName && IsAdd || ...
var ...
7
votes
5answers
2k views
XSLT and possible alternatives [closed]
I had a look at XSLT for transforming one XML file into another one (HTML, etc.). Now while I see that there are benefits to XSLT (being a standardized and used tool) I am reluctant for a couple of ...
2
votes
4answers
239 views
Why should IQueryProvider implementations throw NotSupportedExceptions?
Searching the web, we can find plentiful examples of various ORMs (nHibernate, EF, LinqToSql, etc.) that implement but don't actually support the full IQueryable<T> interface, throwing ...
4
votes
1answer
2k views
Why is imperative programming preferred over functional programming? [closed]
Background: I am proponent of functional programming who works at a VB.NET shop where the prevailing mental model is imperative programming. Being that foundation of our system is WinForms I can ...
2
votes
1answer
342 views
Is it okay to convert dataset from stored procedure to IEnumerable
So, I am working on a project with a team and we are using Entity Framework. We basically want to use linq to entities, and not use stored procedures. I use quite a bit of lists and IEnumerables and ...
2
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2answers
375 views
Style for creating IEnumerable unions
There isn't any cool LINQ sugar for creating unions. The Enumerable.Union() method is usually called like this:
var bigList = list1.Union(list2);
The alternative is to call Enumerable.Union() which ...
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3answers
1k views
What problem domain is LINQ made for?
Each time I see a question posted on Stack Overflow on C#, I see at least one or two answers posted that solve a problem with LINQ. Usually people with very high reputation seem to use LINQ like pros.
...
3
votes
2answers
3k views
Is it better to create a stored procedure or entities to get to the data I need?
I just jumped into a new project with a new company using Entity Framework and ASP.NET MVC 4. I am no expert on Entity Framework, but I think I have a decent grasp of how to use it.
From what I can ...
45
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5answers
24k views
for vs. foreach vs. LINQ
When I write code in Visual Studio, ReSharper (God bless it!) often suggests me to change my old-school for loop in the more compact foreach form.
And often, when I accept this change, ReSharper goes ...
3
votes
1answer
305 views
Algorithm to optimize grouping
I would like to know if there's a known algorithm or best practice way to do the following:
I have a collection with a subcollection, for example:
R1 R2 R3
-- -- --
M M M
N N
L L
A
What i ...
3
votes
5answers
296 views
Using 'new' in a projection?
I wish to project a collection from one type (Something) to another type (SomethingElse). Yes, this is a very open-eneded question, but which of the two options below do you prefer?
Creating a new ...
2
votes
1answer
3k views
Nesting Linq-to-Objects query within Linq-to-Entities query –what is happening under the covers?
var numbers = new int[] { 1, 2, 3, 4, 5 };
var contacts = from c in context.Contacts
where c.ContactID == numbers.Max() | c.ContactID == numbers.FirstOrDefault()
...
2
votes
1answer
221 views
Are elements returned by Linq-to-Entities query streamed from the DB one at the time or are they retrieved all at once?
Are elements returned by Linq-to-Entities query streamed from the database one at the time ( as they are requested ) or are they retrieved all at once:
SampleContext context = new ...
2
votes
4answers
560 views
What is the most effective order to learn SQL Server, LINQ, and Entity Framework?
I am trying to get some advice on what order I should learn about SQL Server, LINQ, and Entity Framework to be able to better work with ASP.NET Webforms and MVC.
From what I've been able to learn so ...
2
votes
1answer
301 views
Better way to read XML
We are storing config files as XML. With that being said, when reading the XML file, is it better to use LINQ to query the XML file or would using the XMLDocument and/or XMLNode classes better to use?
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58
votes
11answers
7k views
Why is the use of abstractions (such as LINQ) so taboo?
I am an independent contractor and, as such, I interview 3-4 times a year for new gigs. I am in the midst of that cycle now and got turned down for an opportunity even though I felt like the ...
2
votes
1answer
719 views
Best way to remove list items from an existing record
Ok more of a conceptual question here:
Say I have an existing record of type Meeting. When I go to edit the meeting I have a listbox with all current meeting participants, and one with all employees. ...
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votes
2answers
688 views
How do I tell the cases when it's worth to use LINQ?
Many things in LINQ can be accomplished without the library. But for some scenarios, LINQ is most appropriate.
Examples are:
SELECT - ...
4
votes
1answer
408 views
What is Rainbow (not the CMS)
I was reading this excellent blog article regarding speeding up the badge page and in the last comment the author waffles (a.k.a Sam Saffron) mentions these tools:
dapper and a bunch of custom ...
7
votes
2answers
1k views
Does LINQ require significantly more processing cycles and memory than lower-level data iteration techniques?
Background
I am recently in the process of enduring grueling tech interviews for positions that use the .NET stack, some of which include silly questions like this one, and some questions that are ...
3
votes
1answer
300 views
Test bed application for executing LinQ queries against AdventureWorks [closed]
I am looking for a "test bed" application which will help me to learn Linq by writing queries and immediately executing them against the AdventureWorks database.
Why AdventureWorks? Because it is a ...
0
votes
2answers
1k views
LINQ TO SQL or ADO.NET? [closed]
What is the best choice LINQ TO SQL (.DBML) or using ADO.NET with procedures for a database with 29 tables and about 30 concurrent users that will run the system that I am going to build?
I know that ...
4
votes
3answers
2k views
Is querying KeyValue Pairs efficient compared to two-property objects?
I'm working on a webservice and I'm returning JSON. However, I'm returning a List<KeyValuePair<string, int>>, since that's all I'm really ever going to be dealing with (property => value)
...
4
votes
2answers
1k views
MVVM Reporting App Approach ? Data Access Layer?
I'm trying to follow the MVVM pattern in a reporting / statistics application that I'm making in C# / WPF.
I have made many model classes to hold properties as a starting point. Some of these models ...
3
votes
1answer
518 views
Any changes/improvement for LINQ 2010 vs LINQ 2008
I'm VB.NET user and now learning LINQ. The book I'm reading now focus on LINQ 2008 VB.NET. I want to know whether there are changes/improvement in LINQ 2010?
p/s: I'm reading this book: Pro LINQ ...
3
votes
3answers
2k views
T-SQL stored procs orders of magnitude faster than LINQ
According to answers I've seen on stackoverflow, stored procedures (and to a lesser extent db functions) tend to perform better vs. LINQ + ORM frameworks (e.g. Entity Framework).
I want to determine ...
1
vote
2answers
1k views
Best practice modelling an active record entity using Linq-To-SQL as DAL
Currently I'm starting a new system on my company, and we are using a good separation between models, views and controllers, basically using Asp.Net MVC 3 for the user UI, and a C# class library for ...
-3
votes
7answers
390 views
Selling LINQ To Management
I recently started working at a new company that currently doesn't use linq, but does use C# and the .net framework. I'm coming from a LINQ background, so I'm biased, but I still think there are a ...
5
votes
1answer
11k views
Entity Framework vs. Linq to SQL? [closed]
I'm a little bit confused about these two terms "Linq to SQL" and "Entity Framework". I have the general idea that both of them somehow allow you to refer to database tables as .net objects or ...
7
votes
4answers
2k views
LINQ vs Data Access Layer
I've taught myself always to handle any data access code in a completely separate 'layer' to my business logic and UI code. This has always been a very good architecture for me and any 'rules' or best ...
14
votes
7answers
11k views
What's the best Java equivalent to Linq? [closed]
Are there any libraries in Java that come close to providing the functionality of Linq?
4
votes
3answers
977 views
LINQ to SQL - Business logic in another assembly?
So I am trying my hand at this whole tiered application thing with ASP.NET 4. The software I've developed is a maintenance nightmare and it isn't very well organized. I've done some looking around ...
12
votes
5answers
4k views
Is the potential performance hit from LINQ worth it for improved readability?
We are considering using LINQ (to Objects) in our (commercial grade) projects where performance may be an issue. I have heard it may impact performance, but then the code is so much more readable and ...
5
votes
3answers
1k views
Will there be any official LINQ like lambda based library for C++?
Given C++('11) has lambdas now, will there be any LINQ like higher order function library officially supported later? Is there any such library now being used in any production level code?
Obviously ...
