Object Reference Not Set To An Instance Of Object

Object reference not set to an instance of an object error is one of the most common errors when developing. NET applications. Here are five most common mistakes that result in this error. In this article, also learn how to fix error, object reference not set to an instance of an object.

Why does this error happen?

This error’s description speaks for itself but when you do not have much experience in development, it is very difficult to understand. So, this error description says that an object that is being called to get or set its value has no reference. This means that you are trying to access an object that was not instantiated.

Why should I know this?

This is important in order to avoid runtime errors that could possibly expose your sensitive data and this could lead to a vulnerability breach. Vulnerability breaches are usually used by hackers for a cyber attack to steal your data or to take your server offline.

вот вы описали класс:

вот вы создали экземпляр класса в методе роута:Tours tours = new Tours();

заметьте, конструктор отработал, но поле tourInfos так и осталось не инициализированным
затем вы пытаетесь обратиться к не инициализированному полю объекта

и получаете вполне закономерную ругань платформы на “обращение по несуществующей ссылке”. Вам нужно инициализировать в конструкторе Tours, поле tourInfos (new List()). Но на этом ваша история не закончится, т. на строчках

система вам опять выбросит то же самое исключение, потому что у вас в коллекции tourInfos не существует ни одного экземпляра класса TourInfo, к которому вы пытаетесь обратится по индексу и изменить у него какое-то свойство. Сначала создайте эти объекты, затем добавьте их в лист, а уж потом доставайте их из листа по индексу и заполняйте необходимые свойства(ну или сначала создайте объекты, задайте им свойства, а потом добавляйте в лист).

По идеи должна вернутся строка с двумя JSON массивами, где все кроме beachType будет null.

нет, судя по вашему коду вам вернётся один JSON массив с двумя объектами в нём.

Table Of Contents

  • What Is Object Reference Not Set to an Instance of an Object Error?
  • A Popular Video Fix
  • How to Fix the Object Reference Not Set to an Instance of an Object 1st Fix2nd Fix3rd Fix4th Fix5th Fix
  • 1st Fix
  • 2nd Fix
  • 3rd Fix
  • 4th Fix
  • 5th Fix
  • Forum Feedback

In this post, we provide 5+ fixes for the Object Reference Not Set To An Instance Of An Object Error.

An extremely troublesome error that you may experience if you’re using Windows 7 is known as the object reference not set to an instance of an object error.

If ever you open up a program such as the Autodesk Data Management Server and the “object reference not set to an instance of an object” window appears, it most likely means that there’s an inconsistency in the programming. It can be fixed pretty easily if you know what to do. However, you need to know what is the root cause of the error first and work from there.

World peace2. Solve hunger3. Give better error messages than “Object reference not set to an instance of an object”

Before going to the fixes, you must first know what the error is and what causes it. Now just to give you an idea, this error is usually only shown to programmers. Non-programmers don’t usually see this error since it is usually programming related. However, non-programmers may also see them if ever there are programs used with unreferenced objects.

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The main issue with this error lies in the main software trying to tell you that there is an object that it is trying to reference. However, the object can’t seem to be referenced by the software because the object doesn’t seem to exist. This could be because of certain corrupt data that has been erased. Another cause for an object not to be referenced would be a change in the settings that you weren’t aware of.

In any case, the very nature of this error is actually quite broad which means that you can’t really pinpoint the cause until you really diagnosed the software. But the general cause would be an unreferenced object.

To fix the error, we have provided several methods on how to go about it. All of these fixes are based on common, specific situations that may happen to you. Let’s check out a few of them.

Forum Feedback

To find out more about the object reference is not set to an instance of an object we looked through different forums and message boards. In general, people were interested in object reference is not set to an instance of an object #C, object reference is not set to an instance of an object Unity/Trados/ #C array, and object reference is not set to an instance of an object connection string.

Object Reference Not Set To An Instance Of Object

A novice to programming said that he kept getting the same mistake that an object reference not set to an instance of an object. He didn’t know how to fix it, so he reached out to the community.

They explained that he had run into a case of NullReferenceException. In simple words, he was trying to use something that was null and didn’t exist.

Another poster explained that if you get the object reference not set to an instance of an object you might have forgotten to assign a value to your variables. As a result, your code wouldn’t execute because the variable wasn’t initialized. The solution would be to debug and check which line would throw the exception. Then you should change your variables so that they don’t point to something that doesn’t exist.

Another forum member states that you can avoid the object reference not set to an instance of an object by explicitly checking for null and providing a default value to return when the object can’t be found. He also advised that you work with Debug. Assert when you use values that should never return null so that you can catch the issues immediately.

A person says that when you encounter “Object reference not set to an instance of an object,” it doesn’t necessarily mean that you haven’t initialized an object.

  • He explains that it’s possible that you have declared and initialized the object, but something in your code has invalidated the object.
  • Another possible explanation would be that something in the code should have initialized an object, but it didn’t.
  • However, he adds that you can find the culprit easily by hovering over the valuables because Visual Studio gives you their values.
  • You just have to look for the one labeled “Nothing” and take care of that value.
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Summing Up

Those are some of the most common situations in which you might encounter the object reference not set to an instance of an object error. In the event that you experience any of the situations that we have mentioned above, you may use some of the fixes and diagnosis tips provided per fix. These fixes are suggested by both support teams of Microsoft and Autodesk, so they are proven to work.

If the problem still continues to persist no matter what fix you try to do, then the best thing to do would be to call in an expert to help you. As mentioned above, this type of error is an extremely broad and generic error which is caused by the individual application that you’re using. The root cause would really depend on what happened inside that application.

So the best way would be to contact the support service behind the application and ask them for assistance. They will be the best people to help you with the problem in the event that a DIY diagnosis and a DIY fix can’t seem to work.

Object Reference Not Set To An Instance Of Object

Ryan is a computer enthusiast who has a knack for fixing difficult and technical software problems. Whether you’re having issues with Windows, Safari, Chrome or even an HP printer, Ryan helps out by figuring out easy solutions to common error codes.

How to avoid exposing code and entities?

Objects used in this sample.

  • public class SampleObj
  • public class SampleChildObj

New object not instantiated

Here, we have a sample situation of when we have this error.

  • public IActionResult NewObject()
  • sampleChild.Item2 = “error”;
  • return View();

This happens when you create a new object but do not instantiate it before getting/setting a value.

Condition statement(if, switch)

Here, we have a sample situation of when we have this error,

  • public IActionResult ConditionStatement()
  • if (true == false)
  • sampleChild = new SampleChildObj();
  • sampleChild.Item2 = “”;
  • else
  • sampleChild.Item2 = “error”;
  • return View();

Why does this happen?

This is a very common mistake. It happens when you create an object that is going to be instantiated inside a conditional statement but forgets to instantiate it in one of the conditions and try to read/write on it.

Object Inside Object

Here, we have a sample situation of when we have this error:

  • public IActionResult ObjectInsideObject()
  • sampleObj = new SampleObj();
  • sampleObj.ChildObj.Item2 = “error”;
  • return View();

Why this happens?

It happens when you have an object with many child objects. So, you instantiate the main object but forget to instantiate its child before trying to get/set its value.

Add item in a null list

Here we have a sample situation of when we have this error,

  • public IActionResult AddInNullList()
  • lstSample.Add(“error”);
  • return View();

When you are trying to read/write data in a list that was not instantiated before.

  • Object naming practices, creating a pattern to name variables, services, methods.
  • Security tricks to protect your data.
  • Reading/writing data without breaking your architecture.

Congratulations! You just learned how to deal with the most common daily mistakes.

Download the code from GitHub here.

  • Using Null conditional operators
  • Using the Null Coalescing operator
  • Using nullable datatypes in C#

1) Using Null conditional operators

This method is easier than using an if-else condition to check whether the variable value is null. Look at this example,

int? length = customers?. Length; // this will return null if customers is null, instead of throwing the exception

2) Using the Null Coalescing operator

This operator looks like “??” and provides a default value to variables that have a null value. It is compatible with all nullable datatypes.

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int length = customers?. Length ?? 0; // 0 is provided by default if customers is null

3) Using nullable datatypes in C#

All reference types in C# can have a null value. But some data types such as int and Boolean cannot take null values unless they are explicitly defined. This is done by using Nullable data types.

The best way to avoid the “NullReferenceException: Object reference not set to an instance of an object” error is to check the values of all variables while coding. You can also use a simple if-else statement to check for null values, such as if (numbers!=null) to avoid this exception.

How to Fix the Object Reference Not Set to an Instance of an Object

Let’s say that you have an XML project that made the error. If that is the case, then you need to fix some of the characters in the coding. Here’s what Microsoft Support suggests that you do:

2nd Fix

This fix can be used if you’re using a GPMC to connect to a Windows 7 Server and use a GPO for auditing settings only to come up with the object reference not set to an instance of an object error. If this is the situation, then Microsoft Support suggests that these are the steps to take:

  • Download a supported hotfix from the Microsoft website
  • Open up the GPO settings
  • Apply the hotfix on the GPMC

3rd Fix

This next fix is applicable to when you are using Autodesk Vault Products. The first thing that you have to do is try to make a diagnosis from where the error is specifically. Once you make your diagnosis, it’ll be easy to make a fix. Here’s what Autodesk Support suggests that you do:

  • Make sure that the applications are all downloaded in a supported computer.
  • Make sure to install all the latest updates for all Vault applications.
  • Scan your computer to make sure that a virus isn’t the cause of the error.

4th Fix

If you think that the error is happening in the Autodesk Data Management Server (ADMS) Console, then you need to first do a diagnosis and then do a short fix. Autodesk Support also suggests some fixes that can be done:

  • Check if all the vault servers are running properly and are properly configured
  • Set the SQL Security settings on the database properly by ensuring that the databases are detached from the AUTODESKVAULT SQL using the ADMS Console

C:WindowsMicrosoft. NETFramework644. 30319aspnet_regiis. exe -i -enable

5th Fix

If ever the error is happening only with certain CAD data files, then you need to open up the Inventor and try to check the links. Autodesk Support also has some ways on how to fix these kinds of situations:

  • Boot up the file that’s located in the Inventor.
  • Click on the Tools tab and then click on the Links option.
  • Click on the specific linked file and click on the Break Link option.
  • Scan the Autoloader again.

As mentioned earlier, the NullReferenceException indicates that your code is trying to work with an object that has a null value as its reference. This means that the reference object has not been initialized.

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