问在ASP.NET核心应用中使用社交登录时获取URL参数

EN

[AllowAnonymous]
public IActionResult Login([FromQuery] string id)
{
   // So I can capture the Id here 
}

[AllowAnonymous]
public async Task ExternalLogin(string provider, string returnUrl, string myId)
{
   var properties = new AuthenticationProperties
   {
      RedirectUri = "Login/Callback"
   };

    // Add returnUrl to properties -- if applicable
    if (!string.IsNullOrEmpty(returnUrl) && Url.IsLocalUrl(returnUrl))
       properties.Items.Add("returnUrl", returnUrl);

    // Add url param Id to properties -- if applicable
    if (!string.IsNullOrEmpty(myId))
       properties.Items.Add("myId", myId);

     await HttpContext.Authentication.ChallengeAsync(provider, properties);

     return;
}

[AllowAnonymous]
public async Task<IActionResult> Callback()
{
   // I can get user info here once authenticated by social media provider
   var user = HttpContext.User;

   // How do I get myId?
}