Web请求从BV代码调用服务并发送多个变量

Question

我的呼叫代码在VB中而不是C＃中：

我需要从VB.net代码调用C＃中的api服务并发送3个变量。当我使用此代码时，它会返回错误，因为我认为我在哪里发送变量是不正确的。您能否请我引导我一种从VB发送多个变量以调用服务的正确方法？

这是调用服务的VB方法：

        Dim apiUrl As String
        apiUrl = ConfigurationManager.AppSettings("URL").ToString()
        Dim hwr As HttpWebRequest
        hwr = WebRequest.Create(apiUrl + "api/Connect/acc")
        Dim postData = "Id =" & objSession.CurrentObject.Object_ID.ToString() & "&UserName =" & name & "&Reason =" & statusReason
        hwr.Method = "POST"

        Try
            Using wr As WebResponse = hwr.GetResponse()
                If CType(wr, HttpWebResponse).StatusCode = HttpStatusCode.OK Then
                    Using dataStream As Stream = wr.GetResponseStream()
                        Using reader As New StreamReader(dataStream)
                            Dim responseFromServer As String = reader.ReadToEnd()
                            reader.Close()
                        End Using
                    End Using
                    wr.Close()
                End If
            End Using
        Catch ex As Exception
            '...handle error...
        End Try

这是正在API中调用的方法：

    [RoutePrefix("api/Connect")]
    Class
    .......
    [HttpPost]
    [Route("acc")]
    public void CancelTransaction(int Id, string UserName, string Reason)
    {
    ...
    }