Expression Tree with iQueryable

.NET 4.0 Expression Trees: Expression The method "get Item" in type ListT> cannot be found.

The overload you use is for static methods only (see documentation: ...http://msdn.microsoft.com/en-us/library/bb351107.aspx...). And "get_Item" is clearly not a static method. So, you need to use a different method overload. Try this, for example:...return Expression.Call(callExpression.Object, callExpression.Method, callExpression.Arguments.ToArr...

Create a completely dynamic where clause using an expression tree and run it via IQueryable.

This is quite hard to look at in isolation, but the first thing that occurs is that ...Compile... looks out of place for ...IQueryable... - that will ...rarely... work (LINQ-to-Objects being the exception)....An equivalent to ...WhereClause.Invoke(C.ClientID)... is to use ...Expression.Invoke... to call a sub-expression, but even this is flakey: LI...

An expression tree may be sent as a parameter to another expression tree.

I think this does what you are asking for:...Expression<Func<TEntity, bool>> Combined { get { var entity = Expression.Parameter(typeof(TEntity)); var pa = Expression.Invoke(PropertyAccessor, entity); var te = Expression.Invoke(TestExpression, pa); return (Expression<Func<TEntity, bool>>) Expression.Lambda(te,...

Parser tree or expression tree

Your code for creating nodes looks okay to me. The problem is that you need code to figure out how to properly build the binary tree. You can't just stick a node anywhere you find a NULL pointer....Your example expression: ...2*(3+4)*5...Would turn into something like:... * / \ * 5 / \ 2 + / \ 3 4 ...Your teacher should have g...

Building an expression tree using a stack and a binary tree c

for algorithm you are using, operands has no precedence. But in bottom-up shift-reduce parser, it does have precedence as @WhozCraig said at comment of this post below....The operands always be pushed into operand stack and will be popped out 2 and calculated with an operator then pushed again to operand stack as a single operand....For your formul...

Build IQueryable.Any with Expression Trees for LINQ queries

Calling an extension method, like ...Enumerable.Any... or ...Queryable.Any..., is simply a static method call on the sequence and the lambda expression you created for the ...WHERE... clause. You can use ...Expression.Call... to do this:...// for Enumerable.Any<T>(IEnumerable<T>,Predicate<T>) var overload = typeof(Enumerable).GetMethods("Any") ...

How to apply an expression tree for IQueryable?

Simple ...CreateQuery... call does not work, because provider uses data source of the passed expression....Before executing expression you need to replace ...Enumerable.Empty<string>()... by a collection with your data:...using System; using System.Collections.Generic; using System.Linq; using System.Linq.Expressions; public class Program { pu...

Modify the expression tree of IQueryable.Include() to add condition to the join

The include method you use calls the method QueryableExtensions.Include(source, path1) which transforms the expression into a string path. This is what the include method does:...public static IQueryable<T> Include<T, TProperty>(this IQueryable<T> source, Expression<Func<T, TProperty>> path) { Check.NotNull<IQueryable<T>>(source, "source"); Che...

C++ Binary Expression Tree: How do I print an infix expression with appropriate parentheses?

When printing an expression tree in infix form you only need to print parenthesis around sub-expressions (i.e. children) where the operator has a lower precedence than the operator of the main (i.e. parent) expression....As an example, take the following expression tree (in postfix notation) and its infix form....4 5 6 + 7 * + 4 + (5 + 6) * ...

How to extract a where clause expression tree from IQueryable

What you have to do is break down the original ...IQueryable..., extract the source and query expression and then build a new query expression and then a new IQueryable from the source and the new query expression. If there is no ...Where..., just add the condition to the original query....IQueryable<T> q = _context.Set<T>().Where(x => x.Id == 1); ...