我尝试使用. dotnetrdf文档中有一个示例，类似于...
//Create our Storage Provider - this example uses Virtuoso Universal Server
VirtuosoManager virtuoso = new VirtuosoManager("https://myhost.org", 1111, "DB", "username", "password");
//Load the Graph into an ordinary graph instance first
Graph g = new Graph();
virtuoso.LoadGraph(g, new Uri("http://example.org/"));
我用我的凭据替换了用户名和密码，但是当涉及到该virtuoso.LoadGraph行时，我得到一个FormatException说：
The input string has the wrong format with the following stacktrace:
bei System.Number.StringToNumber(String str, NumberStyles options, NumberBuffer& number, NumberFormatInfo info, Boolean parseDecimal)
bei System.Number.ParseInt32(String s, NumberStyles style, NumberFormatInfo info)
bei OpenLink.Data.Virtuoso.TcpConnection.GetEndPoint(String ds)
bei OpenLink.Data.Virtuoso.TcpConnection.Open(ConnectionOptions options)
bei OpenLink.Data.Virtuoso.VirtuosoConnection.CreateInnerConnection(ConnectionOptions options, Boolean enlist)
bei OpenLink.Data.Virtuoso.ConnectionPool.GetConnection(ConnectionOptions options, VirtuosoConnection connection)
bei OpenLink.Data.Virtuoso.VirtuosoConnection.Open()
bei VDS.RDF.Storage.VirtuosoManager.Open(Boolean keepOpen, IsolationLevel level)
bei VDS.RDF.Storage.VirtuosoManager.LoadGraph(IRdfHandler handler, Uri graphUri)
bei VDS.RDF.Storage.VirtuosoManager.LoadGraph(IGraph g, Uri graphUri)
bei VirtuosoTest.MainWindow.LoadGraph() in C:\Users\devfs\Documents\Visual Studio 2015\Projects\Test\VirtuosoTest\VirtuosoTest\MainWindow.xaml.cs:Zeile 40.
bei VirtuosoTest.MainWindow..ctor() in C:\Users\devfs\Documents\Visual Studio 2015\Projects\Test\VirtuosoTest\VirtuosoTest\MainWindow.xaml.cs:Zeile 30.
不幸的是，这在试图找出可能出错的地方时并没有多大帮助。任何想法，我能做些什么来缩小问题范围？
PS：我可以通过 Virtuoso 导体访问https://myhost.org:8890/conductor，我还尝试了端口8890作为参数（但我认为这不是所需的端口），结果相同。如果我省略端口，我会收到错误消息，即目标计算机拒绝连接。
提前致谢，
弗兰克