未定义预定义类型'System.Object'或未导入.net 4.6 [英] Predefined type 'System.Object' is not defined or imported .net 4.6

问题描述

我正在使用MVC 5和.net 4.6创建一个我的移动应用程序也可以连接的Web API.

I'm using MVC 5 and .net 4.6 to create a web API that my mobile app can connect too.

每当我构建项目时，都会出现数百个错误，告诉我我需要添加已经存在的引用，并且项目中的每种类型实际上都不存在.这些错误的一些示例:(不包括标题中的一个)

Whenever I build the project I get hundreds of errors telling me that I need to add references that are already there and that literally every type in my project 'does not exist'. Some examples of these errors: (Not including the one in the title)

我尝试过的事情:

• 通过nuGet添加了对System.Runtime的引用. (来自此问题的建议.)
• 从project.json文件中的框架中删除了aspnetcore50. (另一项建议，

• Added a reference to System.Runtime via nuGet. (A recommendation from this question.)
• Removed aspnetcore50 from the frameworks in the project.json file. (Another recommendation, this question.)
• Restarting VS2015, my machine.
• Going through the nuGet package manager and upgrading every package in my project to the latest.
• Actually making sure I can see the references in the references node of the solution explorer.

更新:-我的project.json文件如下所示. (根据卡尔斯答案进行修改后.错误列表现在减少到十个，但是它们仍然是以前的错误.)

UPDATE: -My project.json file looks like this. (After modifying based on Karls answer. The error list is now down to ten, however they are still the same errors as before.)

{
  "commands": {
    "web": "Microsoft.AspNet.Hosting --server Microsoft.AspNet.Server.WebListener --server.urls http://localhost:5000"
  },
  "dependencies": {
    "Microsoft.AspNet.Server.IIS": "1.0.0-beta5",
    "Microsoft.AspNet.Server.WebListener": "1.0.0-beta5",
    "Microsoft.AspNet.Diagnostics": "1.0.0-beta5",
    "Microsoft.AspNet.Mvc": "6.0.0-beta5",
    "System.Runtime": "4.0.20-beta-23019"
  },
  "exclude": [
    "wwwroot",
    "node_modules",
    "bower_components"
  ],
  "frameworks": {
    "dnx451": {
      "frameworkAssemblies": {
        "System.Data": "4.0.0.0",
        "System.Data.DataSetExtensions": "4.0.0.0",
        "System.Data.Linq": "4.0.0.0"
      }
    }
  },
  "publishExclude": [
    "node_modules",
    "bower_components",
    "**.xproj",
    "**.user",
    "**.vspscc"
  ],
  "version": "1.0.0-*",
  "webroot": "wwwroot"
}

推荐答案

我在这里有点猜测，但您似乎对dnx451使用常规的System.Data.*东西却感到怀疑，但没有什么可做的为dnxcore50做好准备.您是否还以核心版本为目标?或者仅仅是项目创建过程中的剩余内容?如果您要定位核心版本并且仍然使用旧的System.Data.*东西，则需要包装这些程序集中的所有内容.

I'm guessing a bit here but it looks suspicious that you are using the regular System.Data.* stuff for dnx451 but doesn't have anything to make up for it for dnxcore50. Are you targeting the core edition as well or is it just leftovers from project creation? If you want to target the core edition and still use the old System.Data.* stuff you'll need to wrap anything from those assemblies like this.

#if DNX451
// Do some DNX451 specific stuff here
#endif

反之亦然.

#if DNXCORE50
// Do some DNXCORE50 specific stuff here
#endif

但是，如果您尚未考虑支持此功能，我只需从框架列表中删除dnxcore50，您的错误可能就会消失.

But if you aren't thinking about supporting this yet I would simply remove dnxcore50 from the framework list and your errors will probably go away.

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