NET Type Fundamentals, for further information I'd recommend either picking up CLR via C# or reading this MSDN article by the same author - Jeffrey Richter. throw a meaningful exception or give some useful feedback to the user!Īll of the above really just hints of. The main method above can be modified in such a way that the NullReferenceException should never be seen by a user: static void Main(string args) If you are using an API or invoking methods that may return null then it's important to handle this gracefully. The root cause really depends on the specific scenario that you've encountered. This is a very common error and can occur because of all kinds of reasons. ReturnedClass.AnotherExampleMethod() //NullReferenceException here. Var returnedClass = exampleClass.ExampleMethod()
The following code is a simple way of reproducing this: static void Main(string args) Which is the same as Object reference not set to an instance of an object. If you try to access a member of a class instance using a null reference then you get a System.NullReferenceException. Reference types, when declared, do not have a default value: class ExampleClass Boolean variables, when declared, have a default value: bool mybool
Value types are primitives such as integers and booleans or structures (and can be identified because they inherit from System.ValueType). NET are either reference types or value types. HERE to participate the guess, it is a Website application as when I open a webpage (.aspx file) an ASP.NET Development Server is opened with a localhost port number.Variables in.
If I have misunderstood this issue, please feel free to let me know. Or you could get the admin permission in this machine, test it again. So if you really want to make sure that whether it is related to the Admin, please test it in other machine you have the enough permission The Admin rights would be related to your app, if it required specific permission, you need to run your app as the admin. Is admin rights mandatory, if not what might be other solution?<< I read on the forum that admin rights can resolve the issue. If it is the Web site app, check the references of the website in solution explorer, right click the reference in question and select properties. If so, my suggestion is that you could remove the reference of this dll in your project, and then re-add it again. HERE to participate the kind of app are you developing, ASP.NET Web form app or web site app or others? Do you add the specific dll file as the references in your project? Thanks for helping make community forums a great place. We are trying to better understand customer views on social support experience, so your participation in this interview project would be greatly appreciated if you have time. If still no help, maybe you could share us a simple sample, we will test it in our side. In addition, Please also check your Configuration manager. Maybe you could clean and build your app, test it again(without Rebuild). Not a real ASP.net expert, but I just create a default web site app, and then create a simple class library project, and then add the dll file as the references of this web site, if I clean and build the solution, the "Date modified" changed well, so it Ignore it if you are developing a website app, it doesn't have the same settings as other app like C# console app or others. Also, when I right click on a reference file (.dll in my bin folder), there is no property tag/page so I am not able to set Copy Local flag to true. >I tried removing the reference and again adding the reference files, but issue didnt resolved. I doubt that it would be the website app. Guess, it is a Website application as when I open a webpage (.aspx file) an ASP.NET Development Server is opened with a localhost port number.