我也有同样的错误，它在程序集版本和程序集文件版本下划线，所以阅读Luqi答案，我只是把它们作为注释添加了进去，错误就解决了

// AssemblyVersion is the CLR version. Change this only when making breaking    changes
//[assembly: AssemblyVersion("3.1.*")]
// AssemblyFileVersion should ideally be changed with each build, and should help identify the origin of a build
//[assembly: AssemblyFileVersion("3.1.0.0")]

我得到这些错误，因为我试图临时重命名obj文件夹为obj_，然后它自动包含在项目中。然后其中的assembly.cs开始与后来生成的obj文件夹中的正确的程序发生冲突。

编辑AssemblyInfo.cs和#if !NETCOREAPP3_0…# endif

using System.Reflection;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
// General Information about an assembly is controlled through the following
// set of attributes. Change these attribute values to modify the information
// associated with an assembly.

#if !NETCOREAPP3_0  

[assembly: AssemblyTitle(".Net Core Testing")]
[assembly: AssemblyDescription(".Net Core")]
[assembly: AssemblyConfiguration("")]
[assembly: AssemblyCompany("")]
[assembly: AssemblyProduct(".Net Core")]
[assembly: AssemblyCopyright("Copyright ©")]
[assembly: AssemblyTrademark("")]
[assembly: AssemblyCulture("")]

// Setting ComVisible to false makes the types in this assembly not visible
// to COM components.  If you need to access a type in this assembly from
// COM, set the ComVisible attribute to true on that type.
[assembly: ComVisible(false)]

// The following GUID is for the ID of the typelib if this project is exposed to COM
[assembly: Guid("000b119c-2445-4977-8604-d7a736003d34")]

// Version information for an assembly consists of the following four values:
//
//      Major Version
//      Minor Version
//      Build Number
//      Revision
//
// You can specify all the values or you can default the Build and Revision Numbers
// by using the '*' as shown below:
// [assembly: AssemblyVersion("1.0.*")]
[assembly: AssemblyVersion("1.0.0.0")]
[assembly: AssemblyFileVersion("1.0.0.0")]

#endif

我在过去也遇到过这个问题，所以我假定构建过程在提供版本控制时分别提供程序集信息。这将导致重复，因为您的项目在AssemblyInfo.cs文件中也有该信息。所以删除文件，我认为它应该工作。

这里的项目中必须已经有一个AssemblyInfo.cs文件:

解决: —删除任意一个AssemblyInfo.cs

当我的主项目与解决方案位于同一文件夹中时，我就遇到了这个问题，然后我在同一解决方案中有一个位于子文件夹中的独立项目，并且该独立项目使用主项目作为参考。这导致主项目检测到子文件夹bin & obj文件夹创建重复的引用。