我是pretty确保你有一个32位/ 64位的冲突。这听起来像，而其类引用设置为64位的主项目可能会被设置为32位。试着寻找这太问题和this它太。他们两个之间，你应该能够找出您的问题。

I am pretty sure you're having a 32-bit / 64-bit conflict. It sounds like your main project might be set to 32-bit while the class its referencing is set to 64-bit. Try looking at this SO question and this one too. Between the two of them, you should be able to figure out your problem.