防爆pression＆LT; TDelegate＆GT; .Compile和垃圾收集 [英] Expression<TDelegate>.Compile and Garbage Collection

问题描述

当我编译EX pression为可执行code和获得委托 - ？请问code作为垃圾回收时，该委托的引用不再存在。

When I compile an expression into executable code and get the delegate - does the code get garbage collected when no more references to this delegate exist?

请问有任何文件？因为我没有找到任何东西在MSDN有用的。

Is there any documentation on this? Because I didn't find anything useful in the MSDN.

推荐答案

是的，code可以被垃圾收集。当你调用编译对T的前pression，在code编译成一个<一个href="http://msdn.microsoft.com/en-us/library/system.reflection.emit.dynamicmethod.aspx">DynamicMethod,而那些有资格进行垃圾回收。

Yes, the code can be garbage collected. When you call Compile on an Expression of T, the code is compiled into a DynamicMethod, and those are eligible for garbage collection.

事实上，这在MSDN不是说明，但你可以看看的前pression＆LT的执行情况; T＆GT; .Compile在DLR，这是.NET 4.0的船舶：

Indeed it's not indicated on the MSDN, but you can have a look at the implementation of Expression<T>.Compile in the DLR, which is what .net 4.0 ships:

<一个href="http://dlr.$c$cplex.com/SourceControl/changeset/view/54115#990638">http://dlr.$c$cplex.com/SourceControl/changeset/view/54115#990638

虽然编译器的执行是在.NET 3.5中不同的，仍在使用DynamicMethods（来源：我自己，我在单声道实现System.Linq.Ex pressions）

Although the implementation of the compiler was different in .net 3.5, DynamicMethods were still used (source: myself, I implemented System.Linq.Expressions in Mono).

在这里编译EX pression树都没有收藏价值的情况下，当你使用<一个href="http://msdn.microsoft.com/en-us/library/dd728224.aspx">Ex$p$pssion<T>CompileToMethod,那你这是没有用的<一个创建的AssemblyBuilder传递MethodBuilder href="http://msdn.microsoft.com/en-us/library/system.reflection.emit.assemblybuilderaccess.aspx">RunAndCollect标志。

The case where compiled expression trees are not collectible, is when you use Expression<T>CompileToMethod, and that you pass a MethodBuilder from an AssemblyBuilder which was not created with the RunAndCollect flag.

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