我正在用C#(Visual Studio 2015)开发一个程序,我想在某种情况下向用户显示一个toast消息.我从MSDN下载了这段代码,运行正常： @H_403_2@// Get a toast XML template XmlDocument toastXml = ToastNotificationManager.GetTemplateContent(ToastTemplateType.ToastImageAndText04); // Fill in the text elements XmlNodeList stringElements = toastXml.GetElementsByTagName("text"); for (int i = 0; i < stringElements.Length; i++) { stringElements[i].AppendChild(toastXml.CreateTextNode("Line " + i)); } // Specify the absolute path to an image String imagePath = "file:///" + Path.GetFullPath("toastImageAndText.png"); XmlNodeList imageElements = toastXml.GetElementsByTagName("image"); imageElements[0].Attributes.GetNamedItem("src").NodeValue = imagePath; // Create the toast and attach event listeners ToastNotification toast = new ToastNotification(toastXml); toast.Activated += ToastActivated; toast.Dismissed += ToastDismissed; toast.Failed += ToastFailed; // Show the toast. Be sure to specify the AppUserModelId on your application's shortcut! ToastNotificationManager.CreateToastNotifier(APP_ID).Show(toast);

测试完这段代码后,我想将它实现到我的应用程序中.所以我稍微改了一下并尝试运行它.错误消息：

The type “IReadOnlyList<>” is defined in a not referenced assembly. Add a reference to System.Runtime,Version=4.0.0.0,Culture=neutral,PublicKeyToken=b03f5f7f11d50a3a”
(translated)

IEnumerable<>也是如此和IReadOnlyList<>

错误来自这两行：

@H_403_2@for (int i = 0; i < stringElements.Length; i++) { stringElements[i].AppendChild(toastXml.CreateTextNode("Line " + i));

我也尝试添加对System.Runtime的引用.我用NuGet(https://www.nuget.org/packages/System.Runtime/4.0.0/)下载了它.
之后错误消失了,但现在我的代码中的每个单词都被淹没了红色,出现错误,例如“System.Object未定义”等等(但是当我启动它时它仍会运行！).

我能想到的唯一可能的解决方案是System.Runtime已经安装在我的计算机上的某个地方,并且4.0.0是我程序的错误版本.但我无法在任何地方找到它.

PS：这是桌面应用程序,而不是Windows应用程序.