Unity-Technologies/UnityCsReference · error · NotImplementedException

The DialogComplexResult named {0} has not been implemented.

Error message

The DialogComplexResult named {0} has not been implemented.

What it means

Thrown by the default arm of a switch over EditorDialog.DialogResult when converting a complex dialog result to an int button index. The DialogResult enum currently defines Cancel(-1), DefaultAction(0), AlternateAction(1) and all three are handled, so this NotImplementedException is a forward-compatibility guard: it fires only if a new enum member is added to DialogResult without updating DisplayDialogComplex's mapping, or if a caller casts an arbitrary integer into DialogResult.

Source

Thrown at Editor/Mono/EditorUtility.cs:235

        public static int DisplayDialogComplex(string title, string message, string ok, string cancel, string alt)
        {
            var result = EditorDialog.DisplayComplexDecisionDialog(
                titleText: title,
                messageText: message,
                defaultButtonText: ok,
                cancelButtonText: cancel,
                altButtonText: alt);

            switch (result)
            {
                case DialogResult.DefaultAction:
                    return 0;
                case DialogResult.AlternateAction:
                    return 2;
                case DialogResult.Cancel:
                    return 1;
                default:
                    throw new NotImplementedException(string.Format("The DialogComplexResult named {0} has not been implemented.", result));
            }
        }

        public static bool DisplayDialog(string title, string message, string ok, DialogOptOutDecisionType dialogOptOutDecisionType, string dialogOptOutDecisionStorageKey)
        {
            EditorDialog.DisplayAlertDialogWithOptOut(
                titleText: title,
                messageText: message,
                buttonText: ok,
                optOutDecisionType: dialogOptOutDecisionType,
                optOutKey: dialogOptOutDecisionStorageKey);
            return true;
        }

        public static bool DisplayDialog(string title, string message, string ok, string cancel, DialogOptOutDecisionType dialogOptOutDecisionType, string dialogOptOutDecisionStorageKey)
        {
            return EditorDialog.DisplayDecisionDialogWithOptOut(
                titleText: title,

View on GitHub (pinned to 225b0fbdb5)

Solutions

1. If you forked/patched EditorUtility.cs, add a case for the new DialogResult member and return a sensible index.
2. If hitting it after a Unity upgrade, ensure the editor assemblies and EditorDialog.cs are from the same version (mismatched DLLs in the project).
3. If you are casting raw ints to DialogResult, stop — use the documented enum values only.

Example fix

// before
DialogResult result = (DialogResult)3; // out-of-range cast
// after
// only use defined members: Cancel, DefaultAction, AlternateAction

// Only the documented DialogResult values are supported by DisplayDialogComplex's int mapping.
static bool IsKnownResult(EditorDialog.DialogResult r) =>
    r == EditorDialog.DialogResult.Cancel ||
    r == EditorDialog.DialogResult.DefaultAction ||
    r == EditorDialog.DialogResult.AlternateAction;

static bool IsKnownResult(EditorDialog.DialogResult r) =>
    Enum.IsDefined(typeof(EditorDialog.DialogResult), r);

When it happens

Trigger: A future Unity version adds a new DialogResult value (e.g. a third action button) but EditorUtility.DisplayDialogComplex is not updated to return a corresponding int index. A user casts a raw int outside {-1,0,1} to DialogResult and passes it through this switch.

Common situations: Hitting this in practice means an internal Unity version mismatch — a newer editor assembly returned a DialogResult the older/patched EditorUtility.cs does not know about. Almost never seen from user scripts because the dialog UI only ever produces the three handled values.

Related errors

• The DialogOptOut type named {0} has not been implemented.
• Unknown opt out decision type
• Unknown dialog icon type
• Parameter selected must be of type System.Enum
• Parameter enumValue must be of type System.Enum

AI-assisted analysis of Unity-Technologies/UnityCsReference@225b0fbdb5 (2026-08-13). Data as JSON: /api/errors/cceddd82176ae8a8. Report an issue: GitHub.