我已经用这些代码行解决了问题：

Ext.onReady(function () {
Ext.QuickTips.init();
// get rights here

if (roles.length > 0) {
    Ext.override(Ext.Button, {
        initComponent: function () {
            //filter rights here with matching text
            // if length is greater than 0, then enable disable buttons
            if (buttonRights.length > 0) {
                if (this.text == buttonRoles[0].ItemText) {
                    this.setDisabled(!roles[0].IsAllowed);
                }
            }
        }
    });
}
});