1

是否可以通过反射编写以下代码？

    var fake = A.Fake<Foo>(
            o => o.WithArgumentsForConstructor(new[] { "Hello" }));

其中o是：

Action<IFakeOptionsBuilder<T>>

WithArgumentsForConstructor在哪里：

IFakeOptionsBuilder<T> WithArgumentsForConstructor(IEnumerable<object> argumentsForConstructor);

Foo 类是：

class Foo
{
    public Foo(string s)
    {
    }
}

我所做的是：

object fake = typeof(A)
    .GetMethod("Fake", new Type[] { })
    .MakeGenericMethod(new[] { this.targetType })
    .Invoke(null, /* Here I need to pass the lambda. */);
4

3 回答 3

5

是的，可以通过反射来做你建议的事情，但是完全没有必要。像这样自己定义静态方法会更简单：

public static class MyClass
{
    public static T CreateFakeWithArgumentsForConstructor<T>(object[] argumentsForConstructor)
    {
        return A.Fake<T>(x => x.WithArgumentsForConstructor(argumentsForConstructor));
    }
}

现在只需使用反射调用此函数：

var method = typeof(MyClass).GetMethod("CreateFakeWithArgumentsForConstructor", BindingFlags.Public | BindingFlags.Static).MakeGenericMethod(new[] { theType });
method.Invoke(null, argumentsForConstructor);
于 2011-11-22T16:37:28.500 回答
1

如果我正确理解了这个问题，那么以下应该没问题：

Action<IFakeOptionsBuilder<Foo>> fakeOptionsBuilderAction = 
    o => o.WithArgumentsForConstructor(new[] { "", "" });

// You need the BindingFlags as Fake() is a static method:
object fake = typeof(A)
    .GetMethod("Fake", BindingFlags.Public | BindingFlags.Static)
    .MakeGenericMethod(new[] { typeof(Foo) })
    .Invoke(null, new object[] { fakeOptionsBuilderAction });

定义Foo为：

class Foo
{
    public Foo(string one, string two)
    {
    }
}
于 2011-11-20T23:23:42.830 回答
1

最后！:)

困难的部分是，在运行时，我不知道类型，所以泛型不是一个选项（甚至在私有辅助方法上也不行）。

场景是能够做到这一点：

var fake = new Fake<Foo>(o => o.WithArgumentsForConstructor("Hello"));

这是我得到的解决方案：

private IEnumerable<object> argumentsForConstructor;

public object Invoke(IEnumerable<object> parameters)
{
    this.argumentsForConstructor = parameters;

    Type actionType = typeof(Action<>).MakeGenericType(
         typeof(IFakeOptionsBuilder<>).MakeGenericType(this.targetType));

    MethodInfo actionMethod = this.GetType()
        .GetMethod("SetArgumentsForConstructor", BindingFlags.Instance | BindingFlags.NonPublic)
        .MakeGenericMethod(new[] { this.targetType });

    Delegate action = Delegate.CreateDelegate(actionType, this, actionMethod);

    Type fake = typeof(Fake<>).MakeGenericType(this.targetType);
    ConstructorInfo ctor = (from ci in fake.GetConstructors(BindingFlags.Instance | BindingFlags.Public)
                            from pi in ci.GetParameters()
                            where pi.ParameterType == actionType
                            select ci).First();

    return ctor.Invoke(new[] { action });
}

[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Performance", "CA1811:AvoidUncalledPrivateCode", Justification = "This method is used by Reflection. It describes the method that is passed in the Action<IFakeOptionsBuilder<T>> overload of the Fake<T> constructor.")]
private void SetArgumentsForConstructor<T>(IFakeOptionsBuilder<T> o)
{
    if (typeof(T).IsInterface)
    {
        return;
    }

    o.WithArgumentsForConstructor(this.argumentsForConstructor);
}

奇迹般有效。:)

于 2011-11-23T09:47:13.460 回答