The Object reference not set to an instance of an object is a common error that developers notice on .NET app or frameworks. Though plenty of causes can result in such errors, we’ll discuss here some major reasons for the occurrence of such types of errors. 

Usually, the error gets displayed when you try to obtain an object that hasn’t been instantiated yet. You have to ensure that your system doesn’t encounter runtime errors or else, it can lead to a data breach. During any such instance, remote hackers can manipulate your data and even stall your server. 

Fixing object reference not set to an instance of an object c# unity (Basics And Introductory Explanation)

It usually occurs as soon as you get NullReferenceException. When you work on .NET, you have to understand value types and reference types. Value types store the data while reference types don’t hold the data. Under reference types, they hold a specific reference point where object can be stored in memory. 

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For example, a web page link can serve as a reference type while Date/Time serve as value types. A variable can be stored under a reference types. When a reference doesn’t go to a specific object, it’s nullreference. Many of .Net App errors emanate from nullreference. 

How to fix system.nullreferenceexception: ‘object reference not set to an instance of an object’.

This code may generate a nullreferenceexception. But its variable ‘text’ has to be null in it. 

public void MyMethod(string text) 

{ 

  //Throws exception if text == null 

  if (text.ToUpper() == “Hello World”) 

  { 

       //do something 

  } 

} 

You may also get null reference exceptions when any type of object is null. If you haven’t initialized SqlCommand object, it may lead to a serious SQL query error. A null string can be serious in SqlCommand, unless you get it fixed at the earliest. 

SqlCommand command = null; 

//Exception! Object reference not set to an instance of an object 

command.ExecuteNonQuery();

How to Utilise Null Coalescing to Avoid NullReferenceExceptions?

You can use the null coalescing feature—?? operator. It comes with a default value for a previously null-valued variable. 

You can utilize null coalescing using this code: 

List<string> values = null; 

foreach (var value in values ?? new List<string>()) 

{ 

    Console.WriteLine(value); 

} 

The errors may originate due to settings, API-type values or database calls. 

Top 3 tips to prevent system.nullreferenceexception: object reference not set to an instance of an object 

• Assign particular values to each variable.
• If the variable is null, process such codes accordingly.
• Use [?] operator wherever possible

In Conclusion:

The object reference not set to an instance of an object is one of the commonest errors within .NET framework or app. You can use if-conditional statement to understand whether your variable has a specific reference. Such problems occur frequently under .NET framework. 

All reference types within C# come with a null value. However, some data types like int and Boolean don’t have null values if you don’t define them appropriately. You must check all variables before assigning codes to them. You can also ensure that you check if-else statement for null values.