linq-to-sql

Using System.Data.Linq in a Razor view

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You need to import the namespace into your view by adding @using System.Data.Linq at the top of your view. However if you want it in all your views then you need to add <add namespace=”System.Data.Linq” /> to the web.config in your Views folder: <system.web.webPages.razor> <host factoryType=”System.Web.Mvc.MvcWebRazorHostFactory, System.Web.Mvc, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35″ /> <pages pageBaseType=”System.Web.Mvc.WebViewPage”> <namespaces> <add … Read more

Linq-to-sql orderby thenby

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How can I do an orderby thenby using the above syntax without using extension syntax. Use a comma between the fields: orderby a, b And what does the orderby, orderby do? When you use orderby twice in a row the elements conceptually will first be sorted using the first orderby, and then sorted again using … Read more

LINQ Take(); how to handle when null or fewer records than requested available?

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There’s a difference between a null reference and an empty collection. It’s fine to call Take on an empty collection. And the argument specifies a maximum number to take, so it’s also fine to specify more than there are items in the collection. I recommend referring to MSDN for precise details like this. For Linq … Read more

LINQ return items in a List that matches any Names (string) in another list

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var products = shopProducts.Where(p => listOfProducts.Any(l => p.Name == l.Name)) .ToList(); For LINQ-to-Objects, if listOfProducts contains many items then you might get better performance if you create a HashSet<T> containing all the required names and then use that in your query. HashSet<T> has O(1) lookup performance compared to O(n) for an arbitrary IEnumerable<T>. var names … Read more

Automatically Compile Linq Queries

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You can’t have extension methods invoked on anonymous lambda expressions, so you’ll want to use a Cache class. In order to properly cache a query you’ll also need to ‘lift’ any parameters (including your DataContext) into parameters for your lambda expression. This results in very verbose usage like: var results = QueryCache.Cache((MyModelDataContext db) => from … Read more

LINQ across multiple databases

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You can do this, even across servers, as long as you can access one database from the other. That is, if it’s possible to write a SQL statement against ServerA.DatabaseA that accesses ServerB.DatabaseB.schema.TableWhatever, then you can do the same thing in LINQ. To do it, you’ll need to edit the .dbml file by hand. You … Read more

How to dynamically add OR operator to WHERE clause in LINQ

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You can use the PredicateBuilder class: var searchPredicate = PredicateBuilder.False<Songs>(); foreach(string str in strArray) { var closureVariable = str; // See the link below for the reason searchPredicate = searchPredicate.Or(SongsVar => SongsVar.Tags.Contains(closureVariable)); } var allSongMatches = db.Songs.Where(searchPredicate); LinqToSql strange behaviour

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)