expression-trees

I have a projection function that I pass to IQueryable<>.Select() method: private static Expression<Func<VendorPrice, PriceItem>> GetPriceSelector(){ return e => new PriceItem { Id = e.Id, Price = Math.Round(e.Price, 4) }; } Everything works just fine but I want to parameterize it like that: private static Expression<Func<VendorPrice, PriceItem>> GetPriceSelector(Func<VendorPrice, decimal> formula){ return e => new PriceItem { Id = e.Id, Price = formula(e) }; } so that I can call it like prices.Select(GetPriceSelector(e => Math.Round(e.Price, 4))) Unfortunately, EF complains about it: The LINQ

I'm attempting to modify an expression tree that dynamically builds a Contains expression that ultimately results in SQL like P IN (123, 124, 125, 200, 201) to instead check perform range checks, which ultimately results in SQL like (P >= 123 AND P <= 125) OR (P >= 200 AND P <= 201) I'm basing my solution on this post . static public Expression<Func<TElement, bool>> BuildContainsExpression<TElement, TValue>( Expression<Func<TElement, TValue>> valueSelector, IEnumerable<TValue> values) { // Removed for post: Input checks and edge cases var equals = values.Select(value => (Expression)Expression

I am trying to create an expression of the following form: e => e.CreationDate; CreationDate is of type long , however I want the expression to return an object instead. I want to use object as a return type because the expression is built dynamically at runtime based on a query paramater. The query parameter specifies the property to access in the expression, such as: > entities?order=creationDate > entities?order=score As you can see, I can order by different properties with different types, so a return type object would allow me to build the expression as generic as possible. The problem is

We're using compiled Expression Trees to generate code dynamically; some information only available to us at runtime enables us to (in theory) write simpler, faster code. We do get a performance boost in many cases. However, in some cases we get a performance hit. In such cases, the Visual Studio Profiler shows that the difference in performance is due to this method (which doesn't show up at all in statically compiled code) JIT_MethodAccessCheck What does this method do? (Google doesn't have much to say about it). Can I optimize it away somehow? JIT_MethodAccessCheck method performs security

I am trying to create an extension "WhereNot" So I can use: Dim x = "Hello world " Dim y = x.Split.WhereNot(AddressOf String.IsNullOrEmpty) Note that my aim here is to learn linq expressions; not solve my issue. I craated this function: <Extension()> _ Public Function WhereNot(Of TElement)(ByVal source As IQueryable(Of TElement), ByVal selector As Expression(Of Func(Of TElement, Boolean))) As IQueryable(Of TElement) Return source.Where(GetWhereNotExpression(selector)) End Function I don't know how to switch the boolean flag, will the function Negate do it? answers in both vb.net and C# are

Why compiled lambda build over Expression.Call is slightly slower than delegate that should do the same? And how to avoid it? Explaining BenchmarkDotNet results. We are comparing CallBuildedReal vs CallLambda ; others two CallBuilded and CallLambdaConst are "subforms" of CallLambda and shows the equal numbers. But difference with CallBuildedReal is significal. //[Config(typeof(Config))] [RankColumn, MinColumn, MaxColumn, StdDevColumn, MedianColumn] [ClrJob , CoreJob] [HtmlExporter, MarkdownExporter] [MemoryDiagnoser /*, InliningDiagnoser*/] public class BenchmarkCallSimple { static Func