DOWNLOAD C# PREDICATEBUILDER

When this call to Build returns, it's going to have the inner expression, i. And Function t2 t2. The True and False methods do nothing special: I have a generic Build method, so the root expression would be of type TEntity. Call c , paramExp , constExp1 ; case OperatorType.

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True because we're using the And operator.

Dynamic LINQ Query In C# Using Predicate Builder

The productQuery and internationalQuery will run because these properties are defined for Product and InternationalProduct. The True and False methods do nothing special: The resulting InvocationExpression is sort of like the expression-equivalent of a method-call calling a routine by passing in arguments for parameters.

Without writing "by hand" expression code. So, when a navigation property is encountered that is a collection, our lambda expression is going to have to use the Any method before delving deeper into the data model.

Dynamic Predicate Building - Part 1

Entity Framework's query processing pipeline cannot handle invocation expressionswhich is why you need to call AsExpandable on the first object in the query. I also use another Expression, set to the root expression.

End sub But I get an error: So far, so good. Working with Entities Prredicatebuilder Code sample: By continuing to browse this site, you agree to this use.

c# - How does PredicateBuilder work - Stack Overflow

c For example, if TEntity was type Parentand links[counter] was equal to 'Child', expr would become p. That isn't strictly necessary. Asked 7 years, 2 months ago.

Its a silver bullet for our problem. Filtering on anonymous types within a complex query is one such compelling reason. Query explorer WinForms Code sample: Thank you very much!

NET membership and roles Silverlight Code sample: Any ideas how it's implemented? A predicate is a function that returns true or false for an item it evaluates. Querying Silverlight Display code samples Code sample: Say I want to do some complex evaluation in the DB, which returns say a scalar value, and compare it to a variable.

Dynamic LINQ Query In C# Using Predicate Builder

We need PredicateBuilder because combining predicates of either kind is hard in. Call paramExpmconstExp1 ; case OperatorType. And Function t2 t2. The two APIs mirror each other. Scraps of word meat in C and F. Working with multiple models Silverlight Coping with large models and large databases Code sample: So let's dig into it.

Simple console app Silverlight Code sample: There is some maintenance on the typeChain string array, and then actually creating the inner expression that will go into Any.

Here are some examples using the PredicateBuilder predicate expression methods:. You use the IPredicateDescription form when you don't know the type of object to filter at compile time.