Recent questions tagged linq

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linq - Add two Lists of different length in c#

List<double> a = new List<double>{1,2,3}; List<double> b = new List<double>{1,2,3,4,5}; a + b ... loop but is there a better way? using linq? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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linq - EF 4: Removing child object from collection does not delete it - why?

I use Entity Framework 4 and I have parent - child relation with "Cascade Delete" set. So i would expect when i ... is fine. What am I missing? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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linq to sql - Explicit construction of entity type '###' in query is not allowed.

Using Linq commands and Linq To SQL datacontext, Im trying to instance an Entity called "Produccion" from my ... that now allowed in LINQ2SQL? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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linq - .NET List<T> Concat vs AddRange

What is the difference between the AddRange and Concat functions on a generic List? Is one recommended over the other? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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linq - Defining a one-to-one relationship in SQL Server

I need to define a one-to-one relationship, and can't seem to find the proper way of doing it in SQL ... fit when trying to implement this approach. Any ideas? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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linq - What's the difference between IQueryable and IEnumerable

This question already has answers here: Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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linq - Hitting the 2100 parameter limit (SQL Server) when using Contains()

from f in CUSTOMERS where depts.Contains(f.DEPT_ID) select f.NAME depts is a list (IEnumerable<int>) of department ... other way to solve this? thanks so much. Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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linq - Convert String to Int in EF 4.0

Is there any way of doing this at all? I have a string field in the DB and I want to parse it into a ... CAST(v AS Edm.Int32) </DefiningExpression> </Function> Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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linq - Why aren't C# static class extension methods supported?

I know from this question that extension methods can only operate on class instances, not the static class itself. ... ForEach<T> extension for IEnumerable<T>. Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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linq to entities - Best way to check if object exists in Entity Framework?

What is the best way to check if an object exists in the database from a performance point of view? I'm using Entity Framework 1.0 (ASP.NET 3.5 SP1). Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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linq - Only initializers, entity members, and entity navigation properties are supported

I'm getting this exception : The specified type member 'Paid' is not supported in LINQ to Entities. Only initializers, ... Paid == false); return View(debts); } Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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linq - How to combine more than two generic lists in C# Zip?

I have three (it's possible to have more than 3-4 generic list, but in this example let 3) generic lists. List<string ... c = {"otherValue"} } How to do that ? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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linq - How to filter nested collection Entity Framework objects?

Here is the problem: I need to return a collection of objects with filtered nested collections. E.g: there is ... flag set as true stay in the collection. Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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linq - How can I do an OrderBy with a dynamic string parameter?

I want to do this: var orderBy = "Nome, Cognome desc"; var timb = time.Timbratures.Include(" ... OrderBy overload available that accepts a string parameter? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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linq - Reading a file line by line in C#

I am trying to read some text files, where each line needs to be processed. At the moment I am just using a ... me when other values are read break; } } } Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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linq - How many Include I can use on ObjectSet in EntityFramework to retain performance?

I am using the following LINQ query for my profile page: var userData = from u in db.Users .Include("UserSkills. ... much? Should I do it in some other way? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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linq - Entity Framework: There is already an open DataReader associated with this Command

I am using Entity Framework and occasionally i will get this error. EntityCommandExecutionException {"There is already ... a connection if it is already open. Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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linq - How to retrieve parent child relationship data using entity framework and do pagination/filtering/sorting on it

I have one DB table which is self-referenced to form the parent child relationship. Id Name ParentId 1 A ... -parent-child-relationship-data-using-entity-framework-and-do-pag...

asked Oct 7, 2021 in Technique[技术] by 深蓝 (71.8m points)

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linq - How do I use Entity Framework to find a record in Cosmos with case insensitive conditions

I know tis question has been asked several times on SO but I haven't found a solution that works. It's clear ... entity-framework-to-find-a-record-in-cosmos-with-case-insensitive-c...

asked Oct 7, 2021 in Technique[技术] by 深蓝 (71.8m points)

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linq to sql - i don't know how i will add a condition where in this query

var q = dc.detail_Demandee.Join(dc.lycee, dm => dm.idLycee, ly => ly.idlycee, (dm, ly) => new { iidlycee = ... /65922435/i-dont-know-how-i-will-add-a-condition-where-in-this-query...

asked Oct 7, 2021 in Technique[技术] by 深蓝 (71.8m points)

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linq - Most efficient way to compare two generic lists based on id elements contained within nested list (C#)

I have two generic lists of items each containing a list of suppliers and their id's: List<ExisitingItems> List< ... to-compare-two-generic-lists-based-on-id-elements-contained-w...

asked Oct 7, 2021 in Technique[技术] by 深蓝 (71.8m points)

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linq - Transform a DataTable into Dictionary C#

I want to know how to transform a DataTable into a Dictionary. I did something like this. using System. ... .com/questions/19712958/transform-a-datatable-into-dictionary-c-sharp...

asked Oct 7, 2021 in Technique[技术] by 深蓝 (71.8m points)

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linq - FirstOrDefault() result of a struct collection?

So I've got a collection of structs (it's actually a WCF datacontract but I'm presuming this ... /stackoverflow.com/questions/15407065/firstordefault-result-of-a-struct-collection...

asked Oct 7, 2021 in Technique[技术] by 深蓝 (71.8m points)

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linq - FirstOrDefault() result of a struct collection?

So I've got a collection of structs (it's actually a WCF datacontract but I'm presuming this ... /stackoverflow.com/questions/15407065/firstordefault-result-of-a-struct-collection...

asked Oct 7, 2021 in Technique[技术] by 深蓝 (71.8m points)

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linq - SingleOrDefault() method: what is "a default value"?

I'm testing for the existence of a user record in the following statement: if (fromUser.AllFriends.Where(af ... com/questions/3713122/singleordefault-method-what-is-a-default-value...

asked Oct 6, 2021 in Technique[技术] by 深蓝 (71.8m points)

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linq - SingleOrDefault() method: what is "a default value"?

I'm testing for the existence of a user record in the following statement: if (fromUser.AllFriends.Where(af ... com/questions/3713122/singleordefault-method-what-is-a-default-value...

asked Oct 6, 2021 in Technique[技术] by 深蓝 (71.8m points)

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974 views

1 answer

linq to sql - Explicit construction of entity type '###' in query is not allowed.

Using Linq commands and Linq To SQL datacontext, Im trying to instance an Entity called "Produccion" from my ... /explicit-construction-of-entity-type-in-query-is-not-allowed...

asked Oct 6, 2021 in Technique[技术] by 深蓝 (71.8m points)

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linq to sql - Explicit construction of entity type '###' in query is not allowed.

Using Linq commands and Linq To SQL datacontext, Im trying to instance an Entity called "Produccion" from my ... /explicit-construction-of-entity-type-in-query-is-not-allowed...

asked Oct 6, 2021 in Technique[技术] by 深蓝 (71.8m points)

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