我在调用WCF服务时收到一个FaultException,如下所示:
2012-04-02 16:26:00.3593|Error|System.ServiceModel.FaultException`1[System.ServiceModel.ExceptionDetail]: The type initializer for 'vService.CheckService' threw an exception. (Fault Detail is equal to An ExceptionDetail, likely created by IncludeExceptionDetailInFaults=true, whose value is:
System.TypeInitializationException: The type initializer for 'vService.CheckService' threw an exception. ----> System.NullReferenceException: Object reference not set to an instance of an object.
at vService.CheckService..cctor() in d:\working\code\VioletServer\vService\CheckService.cs:line 14
--- End of inner ExceptionDetail stack trace ---
at vService.CheckService..ctor()
at CreatevService.CheckService()
at System.ServiceModel.Dispatcher.InstanceProvider.GetInstance(InstanceContext instanceContext, Message message)
at System.ServiceModel.Dispatcher.InstanceBehavior.GetInstance(InstanceContext instanceContext, Message request)
at System.ServiceModel.InstanceContext.GetServiceInstance(Message message)
at System.ServiceModel.Dispatcher.InstanceBehavior.EnsureServiceInstance(MessageRpc& rpc)
at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage41(MessageRpc& rpc)
...).
CheckService.cs的第14行是
private static string connStr = ConfigurationManager.ConnectionStrings["violetdb"].ConnectionString;
在此背景下,异常是什么意思,我该如何解决?
//CheckService.cs
public class CheckService : ICheckService
{
private static string connStr = ConfigurationManager.ConnectionStrings["violetdb"].ConnectionString;
MessageRepository _repo = new MessageRepository(connStr);
public CheckService(){}
public CheckService(MessageRepository repo)
{
_repo = repo;
}
public void SendMessage(string sender, string recipient, string messagetext)
{
_repo.DeliverMessage(sender,recipient,messagetext);
}
}
答案 0 :(得分:4)
您的WCF服务很可能在其应用程序配置文件中没有名为“violetdb”的连接字符串。
在这种情况下会引发TypeInitializerException
,因为您有一个static
字段,该字段在类型构造之前被初始化,并且ConnectionStrings["violetdb"]
调用正在返回null
,它正在抛出一个NullReferenceException
。
底线,检查配置文件的<connectionStrings>
部分,确保连接字符串存在。