FieldInfo.GetValue为私有成员返回null，而调试器指示字段为非null？(FieldInfo.GetValue return null for a private member while debugger indicates field is non null?)

FieldInfo.GetValue为私有成员返回null，而调试器指示字段为非null？(FieldInfo.GetValue return null for a private member while debugger indicates field is non null?)

在C＃/ .ET 4.0中，我试图通过反射检索字段值：

var bar = foo.GetType() .GetField("_myField", BindingFlags.Instance | ) .GetValue(foo)

我对这种情况感到有些困惑。 返回的值为null ，但是，字段（通过调试器观察时）不为null。 更令人费解的是，上面的代码适用于其他对象属性。

唯一奇怪的方面是两个标志IsSecurityCritical和IsSecuritySafeCritical是true ，但我甚至不确定它实际上与情况有关。

我最终会遇到一个小的HttpModule。

public class MyModule : IHttpModule { public void Init(HttpApplication context) { context.BeginRequest += BeginRequest; } void BeginRequest(object sender, EventArgs e) { var app = (HttpApplication)sender; var rawContent = typeof(HttpRequest) .GetField("_rawContent", BindingFlags.Instance | ) .GetValue(app.Request); // at this point 'rawContent' is null, while debugger indicates it is not. } }

任何可以解释这种行为的建议？

In C# / .ET 4.0 I am trying to retrieve a field value through reflection with:

var bar = foo.GetType() .GetField("_myField", BindingFlags.Instance | ) .GetValue(foo)

I am a bit puzzled by the situation. The value returned is null, and yet, the field (when observed through the debugger) is not null. Even more puzzling, the code here above works for the other object properties.

The only odd aspect are the two flags IsSecurityCritical and IsSecuritySafeCritical that are true, but I am not even sure it's actually relevant to the situation.

I am ending up in such a situation with a small HttpModule.

public class MyModule : IHttpModule { public void Init(HttpApplication context) { context.BeginRequest += BeginRequest; } void BeginRequest(object sender, EventArgs e) { var app = (HttpApplication)sender; var rawContent = typeof(HttpRequest) .GetField("_rawContent", BindingFlags.Instance | ) .GetValue(app.Request); // at this point 'rawContent' is null, while debugger indicates it is not. } }

Any suggestion that would explain such a behavior?

最满意答案

这是由.net 4.0中的安全模型引起的，因为您正在运行一个应用程序，该应用程序可能无法完全信任。 由于该字段对安全性至关重要，因此无法通过反射访问它。

您可以在msdn上阅读一些关于： 反射的安全注意事项

This is caused by the security model in .net 4.0, as you're running an application, which is probably not running in full trust. As the field is security critical, you can't access it through reflection.

You can read a bit on the msdn about: Security Ciderati for Reflection