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Query - Counting percent of rows with category out of total number of rows using Dynamic Linq. C# - Dynamic LINQ: Specifying class name in new clause. Extending DynamicLINQ language: Specifying class name in "new" clause. Between Operator Sample. The Between operator is a sample Sequence operator that returns elements after a StartPredicate has been satisfied, until an End Predicate is satisfied.

Between Operator Sample

It is written as a sample and the operator could be implemented in alternative ways using the SkipWhile operator and the TakeWhile operators using a normal query. The only information we have on the source sequence is that it is IEnumerable The code behind this operator shows remarkable similarity to the Sequence.cs source code supplied by Microsoft as part of the MAY 2006 LINQ CTP. This is intentional, the patterns shown in the Standard Query Operators should be the basis for all of our operators to ensure a consistent developer experience when using them. We should throw similar exceptions, and use the delegate prorotypes that all the other operators use. Back to Writing Operators Edit The Code using System; using System.Collections.Generic; using System.Text; using System.Query; public static IEnumerable static IEnumerable Edit The Unit Tests.

C# 4.0/3.0 in a Nutshell - PredicateBuilder. Dynamically Composing Expression Predicates Suppose you want to write a LINQ to SQL or Entity Framework query that implements a keyword-style search.

C# 4.0/3.0 in a Nutshell - PredicateBuilder

In other words, a query that returns rows whose description contains some or all of a given set of keywords. We can proceed as follows: IQueryable<Product> SearchProducts (params string[] keywords) { IQueryable<Product> query = dataContext.Products; foreach (string keyword in keywords) { string temp = keyword; query = query.Where (p => p.Description.Contains (temp)); } return query; } The temporary variable in the loop is required to avoid the outer variable trap, where the same variable is captured for each iteration of the foreach loop.

So far, so good. Of all the things that will drive you to manually constructing expression trees, the need for dynamic predicates is the most common in a typical business application. Using PredicateBuilder Here's how to solve the preceding example with PredicateBuilder: Using jqGrid’s search toolbar with multiple filters in ASP.NET MVC. Download sample - 350 KB Introduction Very often, we have a requirement to display data in tabular form and manipulate it.

Using jqGrid’s search toolbar with multiple filters in ASP.NET MVC

In classic ASP.NET, built-in controls are available. Dynamic LINQ (Part 1: Using the LINQ Dynamic Query Library) LINQ (language integrated query) is one of the new features provided with VS 2008 and .NET 3.5.

Dynamic LINQ (Part 1: Using the LINQ Dynamic Query Library)

LINQ makes the concept of querying data a first class programming concept in .NET, and enables you to efficiently express queries in your programming language of choice. One of the benefits of LINQ is that it enables you to write type-safe queries in VB and C#. This means you get compile-time checking of your LINQ queries, and full intellisense and refactoring support over your code: While writing type-safe queries is great for most scenarios, there are cases where you want the flexibility to dynamically construct queries on the fly. For example: you might want to provide business intelligence UI within your application that allows an end-user business analyst to use drop-downs to build and express their own custom queries/views on top of data.

C# - Dynamic LINQ - Is There A .NET 4 Version. Parsing a string C# LINQ expression. LINQ to SQL: Five Steps to Better Performance. In-Depth Five Tips to Improve LINQ to SQL Performance LINQ to SQL is a powerful technology that can do as much harm as good if it is mis-used.

LINQ to SQL: Five Steps to Better Performance

Here is how to get more out of your LINQ to SQL efforts. Remember the old adage, "The greatest strength of the C language is also its greatest weakness? " It sounds like a paradox, but is absolutely true. LINQ to SQL is much the same way. Tip #1: Ditch the Extra Baggage with ObjectTrackingEnabled I'm a hiker, so I like hiking analogies. In Colorado we have 54 mountains that exceed 14,000 feet in elevation. When I'm preparing for a 14er hike, I pack a lot more gear than I would for a short hike within a few minutes of my house.

LINQ to SQL, by default, behaves like it's going on a 14er hike. That's where the ObjectTrackingEnabled property of the DataContext comes in. The performance boost does come at a small price, however. Now suppose I re-wrote the code to look like this: My LINQ query might look like this: SELECT [t0]. Conclusion Let's face it.