异步反射获取字段

Question

我试图使用汇编中的反射来获取公共字段.

程序集只包含一个类,如下所示:

public abstract class User
{
        private object _iAmPrivateField;
        protected object IAmProtectedField;
        internal object IAmInternalField;
        public object IAmPublicField;

        private void IAmPrivateMethod() { }
        protected void IAmProtectedMethod() { }
        internal void IAmInternalMethod() { }
        public void IAmPublicMethod() { }

        private object IAmPrivateProperty { get; set; }
        protected object IAmProtectedProperty { get; set; }
        internal object IAmInternalProperty { get; set; }
        public object IAmPublicProperty { get; set; }              
}

这是从给定程序集中检索公共字段的方法:

public FieldInfo[] GetPublic(Assembly assembly)
{
     return assembly.GetTypes()
                    .SelectMany(x => x.GetFields(BindingFlags.Public | BindingFlags.Instance))
                    .Where(x => x.IsPublic).ToArray();
}

上面的例子按预期工作 - 结果是1.

但是我在类中添加了异步方法

public async Task IAmAsyncMethod() { }

经过上述更改后,GetPublic()返回4而不是1.

是否有选项可以过滤GetFields()仍然返回1的这些字段？

Answer 1

异步通过发出包含有关异步状态机的信息的额外类来工作.如果使用反汇编程序(如ILSpy)检查程序集,则可以看到它.有关此概念的更多信息,请参阅https://www.markopapic.com/csharp-under-the-hood-async-await/或Google"c#async state machine".还为使用的方法生成状态机yield return ...

这是您自动生成的异步状态机的样子,由ILSpy反编译:

[CompilerGenerated]
[Serializable]
private sealed class <>c
{
    public static readonly Program.<>c <>9 = new Program.<>c();

    public static Func<Type, IEnumerable<FieldInfo>> <>9__0_0;

    public static Func<FieldInfo, bool> <>9__0_1;

    internal IEnumerable<FieldInfo> <Main>b__0_0(Type x)
    {
        return x.GetFields(BindingFlags.Instance | BindingFlags.Public);
    }

    internal bool <Main>b__0_1(FieldInfo x)
    {
        return x.IsPublic;
    }
}

您可以通过检查来省略特殊的自动生成的类CompilerGeneratedAttribute.将您的代码修改为:

return assembly.GetTypes()
    .Where(t => t.GetCustomAttribute<CompilerGeneratedAttribute>() == null)
    .SelectMany(x => x.GetFields(BindingFlags.Public | BindingFlags.Instance))
    .Where(x => x.IsPublic)
    .ToArray();