IsValid

Destroying a GameObject or Component doesn't erase the C# reference. Any variable that was pointing to it still holds a non-null object - it's just a dead one. Accessing its properties will do nothing useful or throw an exception.

This is why you can't rely on a plain != null check:

// ❌ Wrong - the reference is still non-null after Destroy()
if ( myObject != null )
{
    myObject.DoSomething(); // might throw an exception or do nothing
}

// ✅ Correct
if ( myObject.IsValid() )
{
    myObject.DoSomething();
}

You do not need to check for null separately. myObject.IsValid() is safe even if myObject is null.

Common Patterns

Checking before use

void Update()
{
    if ( !_target.IsValid() ) return;

    var dist = WorldPosition.Distance( _target.WorldPosition );
}

Filtering a list after a frame

// Remove any destroyed targets from your list
_targets.RemoveAll( t => !t.IsValid() );

Callbacks and delayed code

Async gaps and timers are common places where objects can be destroyed between frames:

async Task ShootAfterDelay()
{
    await Task.DelaySeconds( 1.0f );

    // The object might have been destroyed during the delay
    if ( !this.IsValid() ) return;

    FireProjectile();
}

this.IsValid() works on your own components too. It's a safe way to guard async callbacks after awaiting.

Referenced API

Canonical API pages mentioned in this guide.

Sandbox.Component

A GameObject can have many components, which are the building blocks of the game.

Sandbox.GameObject

An object in the scene. Functionality is added using Components. A GameObject has a transform, which explains its position, rotation and scale, relative to its parent. It also has a name, and can be enabled or disabled. When disabled, the GameObject is still in the scene, but the components don't tick and are all disabled.

Editor.BaseScrollWidget.Update

No summary available.

Editor.GameEditorSession.Destroy

No summary available.

Editor.GraphicsItem.Destroy

No summary available.

Editor.GraphicsItem.Update

No summary available.

Editor.MapEditor.HammerSceneEditorSession.Destroy

No summary available.

Editor.QObject.Destroy

No summary available.