"Object reference not set to an instance of an object" error, it kills me

Leonhart

I wrote a project myself. A class provides a method to query from the database and return a string (using the pattern developed by others, I don’t know how the data comes out, so I just use it). Now if another web application references this class and calls this method, everything is normal. But if I use a web service project, refer to this class, return the string returned from the above class as a web method, reference the web service in the web application, call the method, and "Object reference not set to an instance of" will appear. an object" error. The error output with try is
System.Web.Services.Protocols.SoapException: Server was unable to process request. --> Object reference not set to an instance of an object. at System.Web.Services.Protocols.SoapHttpClientProtocol.ReadResponse(SoapClientMessage message, WebResponse response, Stream responseStream, Boolean asyncCall) at System.Web.Services.Protocols.SoapHttpClientProtocol.Invoke(String methodName, Object[] parameters) at WSClient.RemotingServ.ServiceRemoting.GetOptionText() in C:\Inetpub\wwwroot\WSClient\Web References\RemotingClient.cs.uo1 at WSClient. TestRemoting.Button1_Click(Object sender, EventArgs e) in c:\inetpub\wwwroot\wsclient\testremoting.aspx.cs:line 58

Please master guidance. Because of business requirements, my webservice cannot directly access the database, and must get the things in the database through that intermediate class area!

wyb_web

A very common code problem is that you have to create a new object and then reference it somewhere.

money80100

No database processing in web service, is it normal

Leonhart

Because there should be no leakage, the same code, I don’t need webservice to adjust it, but webservice can’t work. After debugging and tracking, the process is the same, that is, a certain object returns empty, but I don’t know why.

No way, I can only access the database through the formed business tier, the web service itself cannot access it, I think there is nothing abnormal

hawk1979

The problem must be in your class

First look at this class of yours, is it wrong when using WS call

hawk1979

Paste your code, just paste the execution path in your class.

Leonhart

In fact, the error in this class is that calling an object returns null. But the point is that I don't need to adjust the web service, this is where I wonder! I posted the code later, which is that tempInvokerFactory returned an error.

public string GetOption()
{
GATServiceInvoker invoker = GATInvoker();
Element element = invoker.ReadDiv("GATID_4ca9b6ce3f49420683ef982c30a5a1cb", "en");
string temp=((TextOptionElement)element.ConcreteElement).OptionText.ToString();
return temp;
}

private GATServiceInvoker GATInvoker()
{
if (tempGatService != null) return tempGatService;
tempGatService = GetInvokerFactory().GetGATServiceInvoker();
tempGatService.ErrorOccurred +=new ErrorOccurredEventHandler(ServiceInvoker_ErrorOccurred);
return tempGatService;
}

private ServiceInvokerFactory GetInvokerFactory()
{
if (tempInvokerFactory != null) return tempInvokerFactory;
tempInvokerFactory = new ServiceInvokerFactory( GetFactory() );
return tempInvokerFactory;
}

private ServiceFactory GetFactory()
{
if (tempFactory != null) return tempFactory;
tempFactory = new ServiceFactory();
return tempFactory;
}