值不能为空。在执行当前Web请求期间生成了未处理的异常

Question

我正在我的localhost中运行我的项目，我在浏览器中指向http://localhost:64495/Service.svc?wsdl以查看它，但我在下面得到一个例外

值不能为空。 参数名称：类型   描述：执行当前Web请求期间发生未处理的异常。请查看堆栈跟踪以获取有关错误及其源自代码的位置的更多信息。

Exception Details: System.ArgumentNullException: Value cannot be null.
Parameter name: type

**Stack Trace**

[ArgumentNullException: Value cannot be null.
Parameter name: type]
   System.Activator.CreateInstance(Type type, Boolean nonPublic) +10898802
   System.Activator.CreateInstance(Type type) +6
   Microsoft.Web.Administration.ConfigurationManager..cctor() +141

[TypeInitializationException: The type initializer for 'Microsoft.Web.Administration.ConfigurationManager' threw an exception.]
   Microsoft.Web.Administration.ConfigurationManager.get_IisBinPath() +17
   Microsoft.Web.Administration.WebConfigurationManager..cctor() +68

[TypeInitializationException: The type initializer for 'Microsoft.Web.Administration.WebConfigurationManager' threw an exception.]
   System.Runtime.AsyncResult.End(IAsyncResult result) +489276
   System.ServiceModel.Activation.HostedHttpRequestAsyncResult.End(IAsyncResult result) +178
   System.ServiceModel.Activation.ServiceHttpModule.EndProcessRequest(IAsyncResult ar) +350382
   System.Web.AsyncEventExecutionStep.OnAsyncEventCompletion(IAsyncResult ar) +9692161