Adding items to JCombobox

hello guys
i added a jcombobox in netbeans and wanted to add items to it using “addItem(“string”)” like this :

private void JComboBoxActionPerformed(java.awt.event.ActionEvent evt) {
JComboBox Liste = new JComboBox();

even tho it shows me no error i cant see anything added to the list, i need your help please and thanks.