Questions tagged [linq]
Language INtegrated Query (LINQ) is a Microsoft .NET Framework component that adds native data querying capabilities to .NET languages.
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Add multiple instances of a property to a list [closed]
I'm a novice programmer asking first question here although I've gotten tons of help from previous questions.
The following code is abstracted from what I currently have working.
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4
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Split IEnumerable by predicate
In order to divide an IEnumerable in C# by a predicate, I implemented the following (in a static class):
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Sort group item by attribute
I have a repository method which retrieve a list of items, for example:
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LINQ Provider: Supporting Projections
Up until recently, my LINQ-to-Sage provider didn't support projections, so the client code had to explicitly "transfer" to LINQ-to-Objects, like this:
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Countable and uncountable sets in .NET (IEnumerable and Predicate)
There is a full featured support of countable sets in .NET: IEnumerable<T>. What about uncountable sets; sets defined by predicate? How can they be ...
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Loading and updating data from system A to system B
I need to transfer purchase order (PO) information from SQL Server into Sage 300 ERP, so using my Linq-to-Sage implementation, I wrote a little console application that connects to a SQL Server ...
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Is my LINQ query safe and efficient?
I am relatively new to LINQ queries as I normally just use plain SQL to get my data back but i am changing for the good - Anyway obviously with SQL you pass in parameters so you do not get any SQL ...
Ted Marley
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Count check before Linq Single() call
Should I check Count before Linq Single() call if I expect only one element?
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PermMissingElem- find the missing element in a given permutation in C#
I just encountered this question in codility but apparently this question has been asked in java already (here, here).
Task description
A zero-indexed array A consisting of \$N\$ different integers ...
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Merging trips to the same location with overlapping dates
I have a SQLite database that only contains the holidays for 1 user.
I have a new Trip object (newTrip) that has a ...
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Retrieving collections from a database
I have two collections that I want to retrieve from the database and associate with each other. My solution works, however I know it isn't the most elegant one. Do you have any suggestions on how to ...
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answer
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Find the odd occurrences in an array
Recently, I came across this problem on Codility. I am aware there is a bit of similarity to this question and this question, but I am trying to achieve this in C#.
The problem is as follows:
A ...
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Conditional aggregate whilst constructing array
I have the following snippet of code which gets a load of time intervals (every hour, every 2 hours etc), then groups the results for each of the intervals (e.g, the max value for each hour). This ...
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disable other default row- Entity framework
I have a table that name is Store , In Store Table , just one row can IsDefault=true at ...
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1
answer
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Map a hierarchy of nested DTO objects to a list of business objects [closed]
Consider I download my data into this data structures:
...
user42412
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2
answers
197
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Stitching Linq with if blocks
I recently learned about Linq's deferred execution and a little clearer understanding of IEnumerable. I came back to some code that I had written and decided to change with Linq extension methods. (...
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Rolling up Invoice Items Matching Certain Criteria
I have a listing of invoice line items that I need to apply some convoluted business logic to. We have another listing of items that I compare the invoice items to and if I find matches, I then need ...
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Find items in collection one that are the greatest value less than an item in collection two
This is hard to explain. I wanted to get all of the items in collection one (ints in the example below) that are the highest values that are lower than any of the items in collection two (otherInts). ...
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Customer search using LINQ followed by conditional filtering of results
I have a search function in my class which checks various class property values for null or certain values and queries the database based on those properties. This how my function looks like now:
<...
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Getting price for one firm by week
I've a lot of data whit prices of a product from different firms by week. I've a class named WeekPrice witch contains a list of ...
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Skip by Id on large list
This is in ASP.NET MVC, but that shouldn't make a difference. I have a large number of rows in my database for Songs.
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Operator-based switch for a database query filter
I am currently working on a method, that can search based on a value and an operator.
Currently I check which operator was supplied to the the method in a switch, and do operations accordingly to it.
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user81696
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Passing model to _layout.cshtml
I have login page that looks like:
It has a ViewModelBase and a ViewModel as:
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OnStartApplicationsCommand function
The foreach loop seems ridiculously lengthy and I am trying to get rid of it altogether is possible. But there are a lot of things happening in there which I need ...
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2
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Distinct List of attribute values from XML, using a pre-defined set of attribute names
I have an XML stream that looks like the following (attribute and node quantity , and node depth reduced for demonstration purposes.)
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1
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LINQ query for a user's submitted time-off requests
What is a better way to create this select statement? I tried to just select 'u' and 'us', but the object properties were not accessible when I did this.
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Using Linq instead of multiple foreach loops
A project I'm working on often has lists within lists within lists etc. The original author often uses complicated linq expressions, but when adapting them I mostly get hopelessly bogged down and ...
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Tracking Entity Changes (not EF)
So, I kept refactoring my Sage300 API wrapper - I wanted the client code to feel just like using Entity Framework - this is the closest I got to it:
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1
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Building expression tree with multiple OrElse
I am creating a way for users to filter results based on start and end values. An example of this would be:
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Paginating blog posts from SQL server using nested LINQ statements
I made an ASP.NET MVC application using Entity Framework for code-first migrations to the SQL Server database. I also use Unity (DI/IoC) for managing the services and repositories.
I made an overview ...
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Method or helper function to return objects from EntityFramework with Linq [closed]
The following code reads from Microsoft EntityFramework 6.0 domain model and returns the single view_patient object. The view_patient object is defined in the backend database and uploaded to the ....
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Converting from strings to byte arrays with LINQ in C#
I'm taking in a string of input from the command line, and when prefixed by 0o or 8# interpreting it as an octal string. I'd ...
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Struct implementation of immutable Maybe<T> monad
I have developed the following implementation of an immutable struct Maybe<T> monad for use in my game project; as an ...
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Convert reader to list of class
Class Student
{
Int studentId,
List<ClassB> Books,
Bool IsPassed
}
Class Book
{
Int bookId,
List<int> pages
}
I am creating a list ...
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Eager Loading Deeply into a Model with a Collection Property Whose Type is Inherited
Visual Studio generated this great route for me, where I can load an entity:
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2
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101
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How to find contradiction in order of items in multiple sequences
Suppose you have several sequences:
A: 1 2 3 4 5
B: 2 4 5
C: 2 1 3 4 5
D: 3 2
Here, some pairs of list contradicts each other, because they ...
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Linq-to-Sage Implementation
Following-up on my last question where I wrapped the Sage API with a familiar IRepository interface, I decided to push the abstraction a step further, and... ...
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LINQ statements that aggregate sums from a List of objects
I'm packaging data for use in a JavaScript charting library that expects a somewhat odd structure of data in which there is an array of labels and an array of ...
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Medical appointment book history
This code correctly returns a View_appointment. Is there a better way to
accomplish this with using left joins and unions? I'm trying to learn Linq a little bit ...
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votes
1
answer
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Pull back records that include child records
I am trying to pull back records that include child records for the View I'm putting together. Right now I have a working Linq statement, but it's big, and I think I could make it cleaner.
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Categorize episode-file names - Follow up
This is a follow up to this question.
I have implemented changes to the code as they were suggested in the previous question and have made a few changes of my own.
But it has been mentioned that the ...
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Convex envelope algorithm of random set of points
This is my "naive" implementation of a convex hull algorithm. By naive I mean that I am not using any of the advanced algorithms that exist to solve this problem.
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Give me thy name, I'll invoke thee
This generic function invokes a property of a given object by name:
...
user42412
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1
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505
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Using LINQ to output SQL data from two tables into XML
I am very new to this. Hope someone could help me suggest how to improve the code.
I have two tables where I need to get the SQL data and output it into XML format. I am using LINQ method. Below how ...
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Joining datatables to create a new datatable
I am joining datatables to create a new datatable:
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Query Builder pattern with use of FluentApi
Recently, I've come up with an idea of building a custom query builder combine with FluentApi.
Expected usage:
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