如果依赖项不匹配，请在解决方案级别的NuGet包管理器中检查Update和consolidated选项卡，协调所有这些。

如果您更改了程序集版本或复制了错误中声明的托管库的不同版本，则以前编译的文件也可能引用了错误的版本。一个“重建所有”(或删除你的“bin”和“obj”文件夹在前面的评论中提到)应该解决这个问题。

为任何人添加我的解决方案，这可能会有所帮助。

I had a ClickOnce solution throwing this error. The app referenced a common "Libs" folder and contained a project reference to a Foo.dll. While none of the projects in the solution referenced the static copy of the Foo.dll in the "Libs" folder, some of the references in that folder did (ie: my solution had refs to Libs\Bar.dll which referenced Foo.dll.) Since the CO app pulled all the dependencies from Libs as well as their dependencies, both copies were going into the project. This was generating the error above.

我通过将我的Libs\Foo.dll静态版本移动到一个子文件夹Libs\Fix\Foo.dll来解决这个问题。此更改使ClickOnce应用程序只使用DLL的项目版本，并且错误消失了。

在我的解决方案中有太多的项目需要逐一检查和单独更新，所以我通过以下方法解决了这个问题:

右键单击我的解决方案并选择“管理解决方案的NuGet包…” 进入更新选项卡 找到受影响的包并选择Update 单击OK，这将使包的所有实例保持最新

就我而言，我将项目升级到。net 4.7.2，但仍然使用旧的visual studio版本(2015年)构建。 当我在VS 2019中构建项目时，构建失败消失了。

I recently hit this problem. In my case, I have NuGet packages on different assemblies. What I had was different versions of the same NuGet packages associated with my own assemblies. My solution was to use the NuGet package manager upon the Solution, as opposed to the individual projects. This enables a "consolidation" option, where you can upgrade your NuGet packages across as many projects as you want - so they all reference the same version of the assembly. When I did the consolidations, the build failure disappeared.