He treated me as / like a stranger. 他待我像陌生人。

请问这里的 as a stranger / like a stranger 是什么成分？是宾补还是方式状语？如果是方式状语，这种方式如何理解呢？

同意2位老师解答观点

理解为“介词短语作宾语补足语和介词短语作方式状语”都不影响对以上句子语言现象分析

Police say they're treating it as a case of attempted murder.

=Police say they are treating it as they are treating a case of attempted murder.

=Police say they are treating it as if it (were) a case of attempted murder 

警方称他们正把它当作一起谋杀未遂案件来处理。

He treated me as a child.
他把我当小孩子看待。

He treated money as having little value.
他认为钱没有多大的价值。

I was treated as a distinguished guest.

他们把我待若上宾。

备注：treat sb as/like 有点区别

(1)treat sb as a stranger  把某人当作一个陌生对待

(2)treat sb like a stranger 把某人像一个某事人对待

He treated the boy as a son（男孩是他的儿子）

He treated the boy like a son（男孩不是他的儿子）

He treated me as / like a stranger. 他待我像陌生人。

这里的 as a stranger / like a stranger 是宾补，不是方式状语。因为这里的 me 与 as a stranger / like a stranger 有逻辑上的主谓关系，即他对待我，就像我是一个陌生人似的。