linq

Linq and streamreader getting lines

Hi, Using LINQ, what is an efficent way to get each string from a tab-delimited .txt file (and then get each word, usually what string.Split(...) does)? var v = from line in File.ReadAllLines() select n Is part of this solution I believe. I don't mind if this uses yield return. EDIT: I've also seen threads on here detailing exact...

Where can I get a good, concise LINQ cheatsheet?

I'd like a cheetsheet that contains the most common keywords and syntax, all contained on a single pdf page. ...

Is this an efficient way of doing a linq query with dynamic order by fields?

I have the following method to apply a sort to a list of objects (simplified it for the example): private IEnumerable<Something> SetupOrderSort(IEnumerable<Something> input, SORT_TYPE sort) { IOrderedEnumerable<Something> output = input.OrderBy(s => s.FieldA). ThenBy(s => s.FieldB); switch (sort) { case S...

Compiled query returns the same thing every time

I have this compiled query: private static Func<DBContext, Foo> FooQuery = CompiledQuery.Compile<DBContext, Foo>( _db => _db.FooTable.SingleOrDefault(f => f.DeletionDate == null || f.DeletionDate > DateTime.UtcNow) ); When I run it once, it returns the expected Foo object. But then, even after that object's DeletionDate is set in...

How do i get all "properties" from xml via linq to xml

XML sample (original link): <records> <record index="1"> <property name="Username">Sven</property> <property name="Domain">infinity2</property> <property name="LastLogon">12/15/2009</property> </record> <record index="2"> <property name="Username">Josephine</property> <property name="Domain">infinity3</property...

How do LINQ queries against the Entity Framework communicate dates to a SQL Server?

I'm using two LINQ queries to access my database using Entity Framework: The first stores a token in the database and gives it a 60 second timeout: string tokenHash = GetTokenHash(); Token token = new Token() { Client = client, Expiry = DateTime.Now.AddSeconds(60), UserId = userId, TokenHash = tokenHash, }; context.AddT...

GetAll or GetList Functions And Performance Problem

Nowadays I see in some developers, use function named GetAll or Getlist in each class. These functions return a list or entity of it's class. After that, they use these function like this: dim k = from t in customer.GetAll, p in Product.GetAll where .... I think there will be a performance problem about this using. Because firstly a...

Linq to Entities : relationship * - *

Hello, I have on my EF Schema a relationship * - * (designed by a middle table with 2 keys). When I want filter on each (ie : I want all market segment filtered by one function), I execute this query : var requete = from mkt in ent.MARKETSEGMENT_MKT where mkt.FUNCTION2_FUN.Where(fu => fu.FUN_ID == FunId).FirstOrDefault().FUN_ID == Fu...

Finding a Content Control in Word based on Tagname

Hi. I'm currenty trying some new things with OpenXml but I recently came across some trouble. As the title says I'm trying to insert data dynamically into a table using Xml. To indentify the table in my Worddoc I've put a Rich Text Content Control arround it. Everything worked & looked fine until I tried to search my document for the t...

Linq casting between types

Is there a better way to cast this list of guid strings to guids using linq: public static IList<Guid> ToGuidList(this IList<string> guids) { IList<Guid> guidList = new List<Guid>(); foreach(var item in guids) { guidList.Add(new Guid(item)); } return guidList; } I looked at: ...

reading value of node that has a specific attribute with Xdocument

Im trying to write a List of 'Documents' from an XML string, but i was wondering what is the best way to get the value of a node of certain attribute. More specifically in the sample I would like to set the value of aDocument.Source to the text "The Source" of the "field" node that has the "Source" value for the "name" attribute. Sampl...

Insert another entity in partial insert,update method of an entity

I use LinqDataSource in my web pages and I want to handle Business rules in Changed event of properties and also OnValidate method of an entity. I can delete other entities in partial delete also, I can upload other entities in partial Insert and Update methos but I can't Insert entites in partial update or delete methods. Example : I ha...

Generated code is different than expected

I am researching how LINQ expressions get compiled into code...more specifically the function chaining that gets generated. (The background reason for this is I wanted to more thoroughly understand the objects that get created during joins. I need to code for a COALESCE in the SELECT for two properties from the different tables.) I tend...

Entity framework update existing entity without ASP.NETMVC TryUpdateModel

Hello, I'm new to EF and I've been using the asp.net mvc databind method to update my models "tryupdatemodel", now I have to update a entity from a service layer, since TryUpdateModel is a asp.net mvc method I can't use it in the services layer. What I need to do to update the data of an entity without using this method? I'm using repo...

LINQ: concatenate multiple int properties into a string

I have an object with two different integer properties in it, and I'm trying to get a a new object in Linq to Entities, combining two integer properties from the same object as concatenated strings, as follows List<DateRange> collection = (from d in context.dates select new DateRange { DateString = from s in context.Seasons wher...

How to use a JOIN in a LINQ query

I have the following table structure, which is imported into an Entity Framework project: (NOTE: I mislabled T1Name as T2Name in Table1) I have labeled the Entity Objects. The many-to-many joint table Table5, is represented as an EntityCollection<Entity4> in Entity3, and as an EntityCollection<Entity3> in Entity4 (EntityCollection<T>...

LINQ Distinct Query

Hello, I have a C# application that loads a List of CLR objects called "Tasks". Each Task has the following properties: public int ID { get; set; } public int TypeID { get; set; } public string TypeName { get; set; } public string Name { get; set; } I am trying to find the unique types of tasks in this list. I thought I would try to ...

Converting String to Long ...in LINQ to Entity Framework using a MySQL adaptor.

I have a table with a column of type varchar where the majority of rows have numerical looking values, that is, each string contains nothing but the digits 0 through 9. +------+ | n | +------+ | 123 | | 234 | | BLAH | -- This row is an exception to the rule. | 456 | | 789 | +------+ In MySQL, this works: SELECT * FROM t WHERE n...

how to write this into linq to object query?

from a list, which got 3 attributes I want to return a new list of that class where attribut1 recurrence in the list equals X for an example this; 1,a,b 1,c,d 1,e,f 2,a,b 2,c,d 3,a,b 3,c,d 3,e,f 4,a,b 5,a,b 5,c,d 5,e,f 6,a,b 6,e,f where X = 1 would return that list 4,a,b where X = 2 would return tha...

How do you pronouce PLINQ

Today in my office there was a question of how to say PLINQ as in "P LINQ" or "plinq" all one word. Does anyone have a definitive answer? ...