[HttpGet]
  public ActionResult<UserInfo> Get()
  {
   return new UserInfo() { Name = "Ron.liang", RegTime = DateTime.Now };
  }

  [HttpGet("{id}")]
  public ActionResult<Dictionary<string, string Get(int id)
  {
   return new Dictionary<string, string> {
    { "Name", "Ron.liang" },
    { "RegTime", DateTime.Now.ToString() }
   };
  }

  // 接口 1 输出
  {
   name: "Ron.liang",
   regTime: "2018-12-05T10:40:37.5090634+08:00"
  }
  // 接口 2 输出
  {
   Name: "Ron.liang",
   RegTime: "2018-12-05T10:40:58.5072645+08:00"
  }

public void ConfigureServices(IServiceCollection services)
{
services.AddMvc().AddJsonOptions(o => o.UseCamelCasing(false)).SetCompatibilityVersion(CompatibilityVersion.Version_2_2);
}

public class UserInfo
{
[StringLength(20), RegularExpression(@"^[a-zA-Z]$")]
public string Name { get; set; }
[StringLength(20), RegularExpression(@"^[a-zA-Z]$")]
public string Title { get; set; }
public DateTime RegTime { get; set; }
}

public class UserInfo
{
[Name]
public string Name { get; set; }
[Name]
public string Title { get; set; }
public DateTime RegTime { get; set; }
}

public class NameAttribute : ValidationProviderAttribute
{
public override IEnumerable<ValidationAttribute> GetValidationAttributes()
{
return new List<ValidationAttribute>
{
new RequiredAttribute(),
new RegularExpressionAttribute(pattern: "[A-Za-z]*"),
new StringLengthAttribute(maximumLength: 20)
};
}
}

namespace Microsoft.AspNetCore.Mvc
{
/// <summary>
/// A filter that specifies the type of the value and status code returned by the action.
/// </summary>
[AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, AllowMultiple = true, Inherited = true)]
public class ProducesResponseTypeAttribute : Attribute, IApiResponseMetadataProvider
{
....

}

//旧的：
@Html.Partial("_StatusMessage", Model.StatusMessage)

// 新的：
<partial name="_StatusMessage", for="StatusMessage" />