import * as i0 from "@angular/core";
export declare class ValidationService {
    private invalidQuestions;
    setInvalid(questionId: string, message: string, pageIndex: number): void;
    clearInvalid(questionId: string): void;
    getFirstInvalid(): {
        id: string;
        pageIndex: number;
    } | null;
    getErrorMessage(questionId: string): string | null;
    clearAll(): void;
    static ɵfac: i0.ɵɵFactoryDeclaration<ValidationService, never>;
    static ɵprov: i0.ɵɵInjectableDeclaration<ValidationService>;
}