When exactly is default used in a switch statement?

I can’t find the documentation on “switch”!

When in very specific terms does a switch statement use default?

Is it when the passed value is null? does 0 count for this? Want to use it with SelectionGrid… I guess I could add one to it in the collecting script.

When the value passed is not equal to one of the cases you defined.

Documentation: if- und switch-Anweisungen: Auswählen eines Codepfads für die Ausführung | Microsoft Learn

(I’m assuming you’re writing in C#, but my statement is valid in pretty much every programming language with a switch statement.)

when all cases “fall-through” is when the default case is used.

int _x = 4;

switch(_x)
{
  case 1:
    break; //x is one
  case 2:
    break; //x is two
  case 3:
    break; //x is three
  default:
    break; //x is something else
}

It can be used as a default, general failover.

Suppose you have a Color enum:

public enum Color
{
    Green,
    Blue,
    .... // 500 values here
}

When using a switch construct with this, you could define how to handle a few options, and leave the rest to be handled as a default:

switch (color) 
{
    case Color.Green:
        // ...
        break;
    case Color.Red:
        // ...
        break;
    default:
        // all other options.
 }