1、通过方法参数获取

可以[FromQuery]用来将特定模型绑定到参数：

[HttpGet]
public IActionResult Get([FromQuery(Name = "appid")] string appid)
{
        Session result = DispatchHelper.GetSession(appid);
        if (result != null)
             return new JsonResult(new { openid = result.openid, session_key = result.session_key, unionid = result.unionid });
         return new NoContentResult();
}

2、通过HttpContext.Request.Query获取

[HttpGet]
public IActionResult GetPage()
{
        string appid = HttpContext.Request.Query["appid"].ToString();
        Session result = DispatchHelper.GetSession(appid);
        if (result != null)
             return new JsonResult(new { openid = result.openid, session_key = result.session_key, unionid = result.unionid });
         return new NoContentResult();
}

3、通过model获取

通过model中指定[FromQuery]参数的属性来获取Url中的参数。

[HttpGet]
public IActionResult GetPage(ApiModel model)
{
    Session result = DispatchHelper.GetSession(model);
        if (result != null)
             return new JsonResult(new { openid = result.openid, session_key = result.session_key, unionid = result.unionid });
         return new NoContentResult();
}

public class ApiModel
{
    [FromRoute]
    public int Id { get; set; }
    [FromQuery]
    public string Url { get; set; }
    [FromQuery]
    public int? PageId { get; set; }
}