我要调用限制输入类型T的通用方法来实现两个接口：

I want to call a generic method that constrains the input type T to implement two interfaces:

interface IA { }
interface IB { }
void foo<T>(T t) where T : IA, IB { }

我该如何解决的最后一行

How can I fix the last line of

void bar(object obj)
{
    if (obj is IA && obj is IB)
    {
        foo((IA && IB)obj);
    }
}

反射可能允许做的电话，但我想留在语言中。

Reflection probably allows to do the call, but I would like to stay within the language.

推荐答案

请问C＃4.0动态关键字让你出狱的（主要）免费的吗？毕竟 - 你已经在做的类型检查

Does the C# 4.0 dynamic keyword get you out of jail (mostly) free? After all - you are already doing the type checking.

interface IC : IA, IB { }

void bar(object obj)
{
  if (obj is IA && obj is IB)
  {
    IC x = (dynamic)obj;
    foo(x);
  }
}

这是否突破，如果FOO试图强制转换参数为T？我不知道。

Does that break if foo tries to cast the parameter to T? I don't know.