expression-trees

I'm basically trying to do this , but I don't know what T will be, so I'm building things up using Reflection and Expression trees. // Input (I don't know about "Book") Type itemType = typeof(Book); // Actual Code // Build up func p => p.AuthorName == "Jon Skeet" ParameterExpression predParam = Expression.Parameter(itemType, "p"); Expression left = Expression.Field(predParam, itemType.GetField("AuthorName")); Expression right = Expression.Constant("Jon Skeet", typeof(string)); Expression equality = Expression.Equal(left, right); Delegate myDelegate = Expression.Lambda(equality, new

Has any work been done on the direct conversion of CIL to LINQ expression trees? This would include class libraries, blogs, books, academic papers, etc. What are the known mismatches between CIL and LINQ Expression API? I have seen a project that significantly extended the Expression API to support an almost complete mapping between C# and LINQ Expressions. What work arounds would be suggested to accommodate any of these mismatches? Is there something fundamentally wrong about converting directly from CIL to LINQ Expressions? If so, why? 来源： https://stackoverflow.com/questions/12824201/how-to

Important The question is not "What does Queryable.OfType do , it's "how does the code I see there accomplish that?" Reflecting on Queryable.OfType, I see (after some cleanup): public static IQueryable<TResult> OfType<TResult>(this IQueryable source) { return (IQueryable<TResult>)source.Provider.CreateQuery( Expression.Call( null, ((MethodInfo)MethodBase.GetCurrentMethod()).MakeGenericMethod( new Type[] { typeof(TResult) }) , new Expression[] { source.Expression })); } So let me see if I've got this straight: Use reflection to grab a reference to the current method (OfType). Make a new method,

I'm trying to write my own toy My Toy Language -> MSIL compiler in order to get a better understanding of how compilers work. I got the parsing and lexing working, I have built the expression trees and using the System.Linq.Expressions expression tree API, I have a working interpreter. Now I would like to emit some real MSIL assemblies. The problem is, I can't figure out how to actually build these assemblies. The MethodBuilder class only accepts raw MSIL method bodies, so I have to get the raw MSIL of my expression tree. Calling Expression.Compile() returns a working delegate but I'm not able

This question already has answers here : How do I create an expression tree to represent 'String.Contains(“term”)' in C#? (4 answers) I'm struggling to build an expression tree so I can dynamically do filtering on some data. I have come up with this, but it fails at the var lambda = line foreach (var rule in request.Where.Rules) { var parameterExpression = Expression.Parameter(typeof(string), rule.Field); var left = Expression.Call(parameterExpression, typeof(string).GetMethod("ToLower", Type.EmptyTypes)); var right = Expression.Constant(rule.Data.ToLower()); var method = typeof(string)