NullReferenceException when trying to set class property

Question

Basically I have 2 classes, \"Manifest\" and \"BrowserAction\", set out like this:

public class BrowserAction
{
    public string default_icon {get; set;}
    pu         


        

Answer 1

Default value for reference-type object is null. You need to create BrowserAction instance on browser_action property before using it.

// Create Manifest instance
Manifest newManifest = new Manifest();

Console.Writeline (newManifest.browser_action == null); // Print true;

// Instantiate BrowserAction on browser_action property
newManifest.browser_action = new BrowserAction();

Console.Writeline (newManifest.browser_action == null); // Print false;

// Now you can use browser_action property
newManifest.browser_action.default_popup = "popup.html";