Class NotEmptyAttribute

Marks a string or collection field as requiring a non-empty value, enforced at runtime by ValidateObject(object).

Inheritance
object
Attribute
NotEmptyAttribute
Inherited Members
Namespace: Scylla.Core.Attributes
Assembly: ScyllaCore.dll
Syntax
[AttributeUsage(AttributeTargets.Field)]
public sealed class NotEmptyAttribute : Attribute
Remarks

Emptiness is evaluated differently depending on the field type:

  • String - the value must not be null, the empty string (""), or consist entirely of whitespace characters. Internally uses IsNullOrWhiteSpace(string).
  • ICollection (arrays, List<T>, etc.) - the collection must not be null and must contain at least one element. Checked via Count.
  • IEnumerable - when the field implements IEnumerable but not ICollection, the validator advances the enumerator by one step to confirm that at least one element exists.
  • Null reference - regardless of type, a null value is always considered empty and will fail validation.

This attribute is applied to fields only (Field) and does not provide any Editor Inspector visualization. For visual feedback in the Unity Inspector, combine it with RequiredAttribute. For null-only checks without emptiness semantics, use NotNullAttribute instead.

Validation is performed by calling ValidateObject(object) on the owning object - typically in Awake or Start. A failed check throws ValidationException with the field name and the configured error message, stopping execution immediately in line with Scylla's fail-fast philosophy. 

public class Player : MonoBehaviour
{
    [NotEmpty("Player name cannot be empty!")]
    [SerializeField] private string _playerName;

[NotEmpty]
[SerializeField] private List<Item> _startingItems;

private void Awake()
{
    /* Throws ValidationException if _playerName is null/empty or _startingItems is empty */
    AttributeValidator.ValidateObject(this);
}



}

Constructors

NotEmptyAttribute()

Initializes a new instance of NotEmptyAttribute that uses the default generated error message when validation fails.

Declaration
public NotEmptyAttribute()
Remarks

When the decorated field fails its emptiness check, AttributeValidator produces the message "Field '{fieldName}' cannot be empty." automatically, where fieldName is the C# name of the annotated field as returned by reflection.

NotEmptyAttribute(string)

Initializes a new instance of NotEmptyAttribute with a custom error message that is used verbatim when validation fails.

Declaration
public NotEmptyAttribute(string errorMessage)
Parameters
Type Name Description
string errorMessage

The human-readable message to include in the thrown ValidationException when the field value is empty. Should clearly state which field failed and what value is expected. Pass null or omit this overload to use the auto-generated message.
Remarks

The supplied errorMessage is stored verbatim and forwarded to ValidationException without modification. There is no validation of the message string itself; passing null here is equivalent to using the parameterless constructor.

Properties

ErrorMessage

Gets the custom error message displayed when validation fails for the decorated field.

Declaration
public string ErrorMessage { get; }
Property Value
Type Description
string

A non-null string containing the developer-supplied error message, or null when the parameterless constructor was used. When null, AttributeValidator generates a default message of the form "Field '{fieldName}' cannot be empty." using the actual C# field name.

Extension Methods

See Also