C# 在我的ASP.net网站的身份验证中从Google帐户获取用户信息

这个问题是关于谷歌认证的，当我试着运行下面的代码页面时成功加载的，但当我用谷歌点击登录按钮时，在调试时显示错误在这一行

错误于

GetExtension<FetchResponse>() 

GetExtension（）

在线

Var fetchResponse = Response.GetExtension<FetchResponse>()

Var fetchResponse=Response.GetExtension（）

那么这一行的问题是什么呢？我试着搜索这个问题，但我没有找到那个解决方案

protected void Page_Load(object sender, EventArgs e)
    {
        OpenIdRelyingParty rp = new OpenIdRelyingParty();
        var r = rp.GetResponse();
        if (r != null)
        {
            switch (r.Status)
            {
                case AuthenticationStatus.Authenticated:
                    NotLoggedIn.Visible = false;
                    Session["GoogleIdentifier"] = r.ClaimedIdentifier.ToString();
                    Response.Redirect("Default4.aspx"); //redirect to main page of your website  
                    var fetchResponse = Response.GetExtension<FetchResponse>();
                    Session["FetchResponse"] = fetchResponse;
                    var response2 = Session["FetchResponse"] as FetchResponse;
                    // Use FormsAuthentication to tell ASP.NET that the user is now logged in,
                    // with the OpenID Claimed Identifier as their username.
                    string uname = response2.GetAttributeValue(WellKnownAttributes.Name.First) ?? "Guest";
                    FormsAuthentication.RedirectFromLoginPage(uname, false);   //(response.ClaimedIdentifier, false);
                    break;

                case AuthenticationStatus.Canceled:
                    lblAlertMsg.Text = "Cancelled.";
                    break;

                case AuthenticationStatus.Failed:
                    lblAlertMsg.Text = "Login Failed.";
                    break;
            }
        }
    }

    protected void OpenLogin_Click(object src, CommandEventArgs e)
    {
        string discoveryUri = e.CommandArgument.ToString();
        OpenIdRelyingParty openid = new OpenIdRelyingParty();
        var b = new UriBuilder(Request.Url) { Query = "" };
        //var req = openid.CreateRequest(discoveryUri, b.Uri, b.Uri);


        //var req = openid.CreateRequest(discoveryUri, b.Uri, b.Uri);
        var req = openid.CreateRequest(discoveryUri);

        // This is where you would add any OpenID extensions you wanted
        // to include in the authentication request. In this case, we are making use of OpenID Attribute Exchange 1.0
        // to fetch additional data fields from the OpenID Provider
        var fetchRequest = new FetchRequest();
        fetchRequest.Attributes.AddRequired(WellKnownAttributes.Contact.Email);
        fetchRequest.Attributes.AddRequired(WellKnownAttributes.Name.First);
        fetchRequest.Attributes.AddRequired(WellKnownAttributes.Name.Last);
        fetchRequest.Attributes.AddRequired(WellKnownAttributes.Contact.HomeAddress.Country);
        req.AddExtension(fetchRequest);


        req.RedirectToProvider();

    }

受保护的无效页面加载（对象发送方，事件参数e）
{
OpenIdRelyingParty rp=新的OpenIdRelyingParty（）；
var r=rp.GetResponse（）；
如果（r！=null）
{
开关（右状态）
{
案例验证状态。已验证：
NotLoggedIn.Visible=false；
会话[“GoogleIdentifier”]=r.ClaimedIdentifier.ToString（）；
Response.Redirect（“Default4.aspx”）；//重定向到网站主页
var fetchResponse=Response.GetExtension（）；
会话[“FetchResponse”]=FetchResponse；
var response2=会话[“FetchResponse”]作为FetchResponse；
//使用FormsAuthentication告诉ASP.NET用户现在已登录，
//使用OpenID声明的标识符作为其用户名。
字符串uname=response2.GetAttributeValue（WellKnownAttributes.Name.First）？？“Guest”；
FormsAuthentication.RedirectFromLoginPage（uname，false）；/（response.ClaimedIdentifier，false）；
打破
案例身份验证状态。已取消：
lblAlertMsg.Text=“已取消。”；
打破
案例身份验证状态。失败：
lblAlertMsg.Text=“登录失败。”；
打破
}
}
}
受保护的void OpenLogin_Click（对象src、CommandEventArgs e）
{
string discoveryUri=e.CommandArgument.ToString（）；
OpenIdRelyingParty openid=新OpenIdRelyingParty（）；
var b=新的UriBuilder（Request.Url）{Query=”“}；
//var req=openid.CreateRequest（discoveryUri，b.Uri，b.Uri）；
//var req=openid.CreateRequest（discoveryUri，b.Uri，b.Uri）；
var req=openid.CreateRequest（discoveryUri）；
//您可以在这里添加所需的任何OpenID扩展
//在本例中，我们使用OpenID属性Exchange 1.0
//从OpenID提供程序获取其他数据字段
var fetchRequest=new fetchRequest（）；
fetchRequest.Attributes.AddRequired（WellKnownAttributes.Contact.Email）；
fetchRequest.Attributes.AddRequired（WellKnownAttributes.Name.First）；
fetchRequest.Attributes.AddRequired（WellKnownAttributes.Name.Last）；
fetchRequest.Attributes.AddRequired（WellKnownAttributes.Contact.HomeAddress.Country）；
请求追加扩展（获取请求）；
req.redirectTopProvider（）；
}

应该是

var fetchResponse = r.GetExtension<FetchResponse>();

var fetchResponse=r.GetExtension（）；

而不是

var fetchResponse = Response.GetExtension<FetchResponse>();

var fetchResponse=Response.GetExtension（）；