¿Cómo se resuelve el error de referencia de objeto que no está configurada como una instancia de un objeto?

How do you resolve the error object reference not set to an instance of an object?

Use Null Coalescing to Avoid NullReferenceExceptions It works with all nullable data types. The following code throws an exception without the null coalescing. Adding “?? new List()” prevents the “Object reference not set to an instance of an object” exception.

The message “object reference not set to an instance of an object” means that you are referring to an object the does not exist or was deleted or cleaned up.

Explanation: The location of the object, that is, the exact memory location is passed, when the object is passed by reference. The pass by reference is actually a reference to the object that the function uses with another name to the same memory location as the original object uses.

A NullReferenceException is thrown when I try to add to the collection. The exact message states: “Object reference not set to an instance of an object”. Public Sub SearchTraverse (ByVal Node As Customer, Surname As String) ‘ Code to search for customers here…

Imports System.Collections.Generic Module Example Public Sub Main () Dim names As List (Of String) names.Add (“Major Major Major”) End Sub End Module ‘ Compilation displays a warning like the following: ‘ Example1.vb (10) : warning BC42104: Variable ‘names’ is used before it ‘ has been assigned a value.

A null reference exception could result ‘ at runtime. ‘ ‘ names.Add (“Major Major Major”) ‘ ~~~~~ ‘ The example displays output like the following output: ‘ Unhandled Exception: System.NullReferenceException: Object reference ‘ not set to an instance of an object. ‘ at Example.Main () Some compilers issue a warning when they compile this code.

By default Json.NET will serialize all objects it encounters by value. If a list contains two Person references and both references point to the same object, then the JsonSerializer will write out all the names and values for each reference.