Expression Tree Tutorial - Knowledge Base (KB)

Linq to SQL query compilation from a non-trivial IQueryable

Is there a way to use the CompiledQuery.Compile method to compile the Expression associated with an IQueryable? Currently I have an IQueryable with a very large Expression tree behind it. The IQueryable was built up using several methods which each supply...

Expression performance when compiled-to-delegate

I'm generating an expression tree that maps properties from a source object to a destination object, that is then compiled to a ...Func<TSource, TDestination, TDestination>... and executed. ...This is the debug view of the resulting ...LambdaExpression...

Performance of Compiled C# Lambda Expressions

Consider the following simple manipulation over a collection:...static List<int> x = new List<int>() { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 }; var result = x.Where(i => i % 2 == 0).Where(i => i > 5); ...Now let's use Expressions. The following code is roughly eq...

Accessing private members from a dynamic assembly in.NET

I'm working on a library that allows users to input arbitrary expressions. My library then compiles those expressions as part of a larger expression into a delegate. Now, for still unknown reasons compiling the expression with ...Compile... sometimes/ofte...

GetCustomAttributes performance issue (expression trees is the solution??)

I have a performance problem because I use reflection and GetCustomAttributes for my data access. The performance profiler detected it. I have an extension method like this:...public static class DataRowExtensions { /// <summary> /// Maps DataRow ...

Performance of expression trees

My current understanding is that 'hard coded' code like this:...public int Add(int x, int y) {return x + y;} ...will always perform better than expression tree code like this:...Expression<Func<int, int, int>> add = (x, y) => x + y; var...

Compiled expression tree performance

If to run ...following code...using System; using System.Linq.Expressions; using System.Diagnostics; public class E { public double V { get; set; } } public class Program { public static void Main() { E e = new E(); Func<doub...

Optimizing Func.Invoke() generated from expression tree

I am working on an automation for instantiating classes dynamically....I decided to write an expression tree that would generate a ...Func..., that could instantiate my class for me. However, I am noticing 3x slower performance of my ...Func... as opposed...