public IActionResult ExternalLogin(string provider, string returnUrl = null)
        {
            var redirectUrl = Url.Action(nameof(ExternalLoginCallback), new { returnUrl });
            var properties  = _signInManager.ConfigureExternalAuthenticationProperties(provider, redirectUrl);

            return(Challenge(properties, provider));
        }
        public IActionResult ExternalLogin(string provider, string returnUrl = null)
        {
            // Request a redirect to the external login provider.
            var redirectUrl = Url.Action("ExternalLoginCallback", "Account", new { ReturnUrl = returnUrl });
            var properties  = _signInManager.ConfigureExternalAuthenticationProperties(provider, redirectUrl);

            return(Challenge(properties, provider));
        }
        public IActionResult LinkLogin(string provider)
        {
            // Request a redirect to the external login provider to link a login for the current user
            var redirectUrl = Url.Action("LinkLoginCallback", "Manage");
            var properties  = _signInManager.ConfigureExternalAuthenticationProperties(provider, redirectUrl, _userManager.GetUserId(User));

            return(Challenge(properties, provider));
        }