您需要在MVC6明确使用FromBody如果您正在使用JSON

You need to explicit use FromBody on MVC6 if you are using json

public JsonResult Login([FromBody]LoginViewModel model)

修改

我觉得你混合不同的错误。我会尽力来形容你应该如何提出请求：

I think you are mixing different errors. I will try to describe how you should make the request:

内容类型的必须：应用程序/ JSON

content-type must be: application/json

您请求主体的必须 JSON格式（如JasonLind建议）：

your request body must be in JSON format (as JasonLind suggested):

{
    UserName: 'Test',
    Password: 'Test',
    RememberMe: true
};

这是你应该看到检查的要求（通过镀铬调试工具F12）时，或使用一个请求检查就像小提琴手。

this is what you should see when inspecting the request (via chrome debugger tools F12) or using a request inspector like fiddler.

如果你看到一些在用户名=测试与放大器的形式;密码=测试和放大器;了rememberMe = TRUE ，那么你就错了，这是形式的格式

If you see something in the form of UserName=Test&Password=Test&RememberMe=true then you are doing it wrong, that's form format.

您不需要模式变量。如果你看到你的要求有一个包装，那么你应该将其删除。

you don't need the model variable. if you see your request with a "wrapper" then you should remove it.