您可能只需要在没有相同错误的情况下添加错误即可.该错误不会进行任何智能的合并/重复消除，它会简单显示所有注册提供商的错误.构建系统注册一个 将错误构建到错误列表的提供程序.如果您有某种MEF组件也在构建系统之外提供了相同的错误，则需要通过检查列表中的错误来确保不提供重复项，然后再进行操作. 提供自己的.

You likely need to only add your errors if the same errors aren't already present.  The error doesn't do any sort of intelligent merging/duplicate elimination, it simply displays errors for all registered providers. The build system registers a provider that pipes build errors to the error list. If you have some kind of MEF component that is also supplying the same errors outside of the build system you would need to make sure that you don't supply duplicates by examining the errors in the list before providing your own.

Ryan