vb.net – Google OAuth令牌错误 – 400错误请求

我正在尝试使用OAuth2验证我的应用程序并使用“已安装的应用程序”流程(获取auth-code然后请求令牌).在GetResponse()行上请求令牌时,我收到400错误请求错误.我的代码如下：

Public Sub New()
    Dim tokenRequest As WebRequest = 
         WebRequest.Create("https://accounts.google.com/o/oauth2/token")

    Dim requestString As String = "code=<auth-code>" _
                        & "&client_id=<client_id>" _
                        & "&client_secret=<client_secret>" _
                        & "&redirect_uri=http://localhost" _
                        & "&grant_type=authorization_code"

    byteArray = StrToByteArray(System.Web.HttpUtility.UrlEncode(requestString))

    tokenRequest.Credentials = CredentialCache.DefaultCredentials
    tokenRequest.Method = "POST"
    tokenRequest.ContentLength = byteArray.Length
    tokenRequest.ContentType = "application/x-www-form-urlencoded"
    Dim dataStream As Stream = tokenRequest.GetRequestStream()

    dataStream.Write(byteArray,byteArray.Length)
    dataStream.Close()

    Console.WriteLine("Getting response...")

    'Get response
    Try
        Dim response As WebResponse = tokenRequest.GetResponse()

        Console.WriteLine(CType(response,HttpWebResponse).StatusDescription)

        Dim data As Stream = response.GetResponseStream

        Array.Resize(byteArray,4096)

        Array.Clear(byteArray,byteArray.Length)

        data.Read(byteArray,byteArray.Length)

        response.Close()

    Catch wex As WebException
       Console.WriteLine("ERROR! : ")
        Console.WriteLine(wex.Message)
        Console.WriteLine(wex.Status)
        Console.WriteLine(wex.Data)
        Console.WriteLine(wex.InnerException.Message)
        Console.WriteLine(wex.HelpLink)
    End Try
End Sub

错误的具体情况如下：

The remote server returned an error: (400) Bad Request.
7
System.Collections.ListDictionaryInternal
System.NullReferenceException: Object reference not set to an instance of an obj
ect.
   at GADownload.GoogleAnalytics..ctor() in ***.vb:line 86
   at GADownload.Main1.Main(String[] args) in ****.vb:line 18

我已经看过Google GetAccessToken : Bad Request 400和Google GData .Net OAuthUtil.GetAccessToken 400 Bad Request,但还没有找到适合此代码的解决方案.我已经检查了所有建议的解决方案并实施了它们,但到目前为止还没有运气.

curl -X POST -d "code=<auth-code>&client_id=<client_id>&client_secret=<client_secret>"&grant_type=authorization_code" http://localhost:8000/auth/token