1、Qt_QComboBox(下拉框)---实现添加下拉选择

    /* 1.下拉框的简单应用 */
    QComboBox *combo_IOnum = new QComboBox(this);

    QStringList strlist; //定义一个列表
    strlist<<"COM1"<<"COM2"<<"COM3"<<"COM4"<<"COM5";
    combo_IOnum->clear();
    combo_IOnum->addItems(strlist);
    combo_IOnum->setEditable(true); //可设置
    qDebug() << strlist;
    qDebug() << combo_IOnum;