User eXperience studies with products, systems or services have significantly increased in companies in order to anticipate their commercial success. Among the user experience dimensions, emotions are predominant. However User eXperience studies used several concepts to refer to emotions and current measures still have some flaws. Consequently, this doctoral project aims firstly to provide a multi-componential approach of emotions based on a psychological view, and secondly to provide Affective Computing solutions in order to evaluate emotions in User eXperience studies. Through a study using hand-gesture interface devices, three components of users' emotions were simultaneously measured with self-reports: the subjective, cognitive and motivational components. The results point out the possibility of measuring different components in order to gain a better understanding of emotions triggered by products. They also point out that self-reports measures could be improved with Affective Computing solutions. In this perspective, two emotion assessment tools were developed: Oudjat and EmoLyse.