Object reference not set to an instance of an object tutorial

"Object reference not set to an instance of an object" I believe that the problem is that whenever you write a code, regardless of the technical level you encounter, it means that we did not initialize the object before referencing the object. This is usually caused by the fact that the object we are referencing is empty. This is often the case when we pass parameters, and we will consider whether the arguments we call are empty. Here is my own problem: I was in the three-tier architecture in the B-Layer call interface when the problem arises, my own analysis is because the called interface has not been successfully created, because I created the interface through the abstract factory. The error points are as follows: The class name in the code is different from the actual class name, and there is a 1 more in the code, although it is a sloppy mistake to make clear the wrong principle. This time may be just the class name is different, next time not necessarily, below is I found from the Internet other possible causes of this error, I hope you can help. 1, Viewstat

1. Problems that both novice and veteran birds cannot avoid--object references are not set to an instance of an object

Summary: "Object references not set to an instance of an object" I believe this is a problem, as long as the code is written, regardless of the technical level will encounter, this sentence means that we have not initialized the object before referencing the object. This is usually caused by the fact that the object we are referencing is empty. This is often the case when we pass parameters, and we will consider whether the arguments we call are empty.

2. Object reference not set to an instance of an object OOP-----Class and Object object

Summary: Object references are not set to an instance of an object: Object references are not set to an instance of an object OOP-----classes and Object objects: Naturally, we see a thing that can quickly reflect what it is, what it can do, it is the knowledge that we accumulate, the way of thinking is innate, Did we ever think about how it was done? ———— analogy with a very simple word. We have a lot of "models" in our heads that help us to understand what we see through these "models", and OOP is based on the idea that we call "models" in our Brains "classes", which are called "Objects" by the objects identified by these "models", with a

3. Object-php Docking Java soap A couple of big God help look at the urgency AH

Introduction: interface side to XML but I can't get through XML data has always been "object reference not set to an instance of an object." ", only the return value is returned with the XML, but it seems that the interface has not received the parameters" Message header group basic information is incomplete, group code, user, password is required "Ini_set (" soap.wsdl_cache_enabled "," 0 "); Header ("Content-type:text/html;charset=utf-8"); $url = ' http:/