private void storePartcipantEditField(TextBox control, IList <ParticipantEdit> items, string propertyName)
        {
            if (control.Text == "<Verschiedene>")
            {
                return;
            }

            foreach (var item in items.Cast <ParticipantEdit>())
            {
                PropertyUtilities.SetPropertyValue(item, propertyName, control.Text);
            }
        }
        private void storePartcipantComboBox(ComboBox control, IList <ParticipantEdit> items, string propertyName)
        {
            if (control.SelectedValue == null)
            {
                return;
            }

            var value = control.SelectedValue;

            foreach (var item in items.Cast <ParticipantEdit>())
            {
                PropertyUtilities.SetPropertyValue(item, propertyName, value);
            }
        }