OpenIdButton'；s扩展返回null

下面是我用vb.net编写的代码

受保护的子OpenIdButton3_LoggedIn（ByVal sender作为对象，ByVal e作为DotNetOpenAuth.OpenId.relingparty.OpenIdEventArgs）处理OpenIdButton3.LoggedIn

OpenIdButton3.Visible=False

作为索赔响应的Dim配置文件=e.Response.GetExtension（索赔响应的）（）

Dim email As String=profile.email

MsgBox（电子邮件）

端接头

但是线路

Dim email As String=profile.email

正在给出以下错误

异常详细信息：System.NullReferenceException:对象引用未设置为对象的实例

我已经阅读了相关文档，并在webconfig中实现了AXFetchAsSregTransform。下面是显示相同内容的块

>

即使这样，我似乎得到了空值。我正在从谷歌获得认证

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有人能帮我吗？

最后，我找到了解决办法。将其张贴在此处，以便其他面临相同问题的人可以得到帮助

“全球声明——如果你出于某种原因在本地声明，它们似乎不起作用

Dim relyingParty作为新的开放式政党

Dim authResponse作为IAAuthenticationResponse

声明此项后，在web表单上创建一个按钮，允许用户登录Google。以及一个显示已登录用户的电子邮件id的标签

'将以下代码放在页面加载上

在按钮的单击事件中输入以下代码

Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click
    Dim currentPageURL As String = curPageURL.ToString

    Dim urlRealm As New Uri(currentPageURL)
    Dim urlReturn As New Uri(currentPageURL)

    Dim rm As Realm = New Realm(urlRealm)
    Dim gIdentifier As String = "https://www.google.com/accounts/o8/id"

    Dim request As IAuthenticationRequest = relyingParty.CreateRequest(gIdentifier, urlRealm, urlReturn)

    Dim fetch As New FetchRequest

    fetch.Attributes.Add(New AttributeRequest(WellKnownAttributes.Contact.Email, True))
    request.AddExtension(fetch)

    request.RedirectToProvider()
End Sub

添加以下两个函数以获取您当前的URL

Function curPageURL() As String
    Dim s, protocol, port As String

    If Request.ServerVariables("HTTPS") = "on" Then
        s = "s"
    Else
        s = ""
    End If

    protocol = strLeft(LCase(Request.ServerVariables("SERVER_PROTOCOL")), "/") & s

    If Request.ServerVariables("SERVER_PORT") = "80" Then
        port = ""
    Else
        port = ":" & Request.ServerVariables("SERVER_PORT")
    End If

    curPageURL = protocol & "://" & Request.ServerVariables("SERVER_NAME") & _
          port & Request.ServerVariables("SCRIPT_NAME")
End Function

Function strLeft(ByVal str1 As String, ByVal str2 As String) As String
    strLeft = Left(str1, InStr(str1, str2) - 1)
End Function

你就完了

      <add type="DotNetOpenAuth.OpenId.Behaviors.AXFetchAsSregTransform, DotNetOpenAuth" />

    </behaviors>

  </relyingParty>

</openid>

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
    Dim googleAppsDiscovery As New HostMetaDiscoveryService() With {.UseGoogleHostedHostMeta = True}
    relyingParty.DiscoveryServices.Insert(0, googleAppsDiscovery)

    authResponse = relyingParty.GetResponse()

    If authResponse IsNot Nothing Then
        If authResponse.Status = AuthenticationStatus.Authenticated Then
            Dim fetch As FetchResponse = authResponse.GetExtension(Of FetchResponse)()
            If fetch IsNot Nothing Then
                ' Save user details in session variables
                'Dim temp As [String]() = fetch.GetAttributeValue(WellKnownAttributes.Contact.Email).ToString().Split("@"c)
                Dim temp As String = fetch.GetAttributeValue(WellKnownAttributes.Contact.Email).ToString()
                If temp IsNot Nothing Then
                    Dim userName As String = temp
                    Label1.Text = "You are logged in as : " & userName
                End If
            End If
        End If
    End If
End Sub

Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click
    Dim currentPageURL As String = curPageURL.ToString

    Dim urlRealm As New Uri(currentPageURL)
    Dim urlReturn As New Uri(currentPageURL)

    Dim rm As Realm = New Realm(urlRealm)
    Dim gIdentifier As String = "https://www.google.com/accounts/o8/id"

    Dim request As IAuthenticationRequest = relyingParty.CreateRequest(gIdentifier, urlRealm, urlReturn)

    Dim fetch As New FetchRequest

    fetch.Attributes.Add(New AttributeRequest(WellKnownAttributes.Contact.Email, True))
    request.AddExtension(fetch)

    request.RedirectToProvider()
End Sub

Function curPageURL() As String
    Dim s, protocol, port As String

    If Request.ServerVariables("HTTPS") = "on" Then
        s = "s"
    Else
        s = ""
    End If

    protocol = strLeft(LCase(Request.ServerVariables("SERVER_PROTOCOL")), "/") & s

    If Request.ServerVariables("SERVER_PORT") = "80" Then
        port = ""
    Else
        port = ":" & Request.ServerVariables("SERVER_PORT")
    End If

    curPageURL = protocol & "://" & Request.ServerVariables("SERVER_NAME") & _
          port & Request.ServerVariables("SCRIPT_NAME")
End Function

Function strLeft(ByVal str1 As String, ByVal str2 As String) As String
    strLeft = Left(str1, InStr(str1, str2) - 1)
End Function