簡單設置qcombobox可以搜索顯示（只能頭部匹配搜索）

pcombobox->setEditable(true);
pCombobox->setInsert Policy(QComboBox::NoInsert);
QCompleter* pCompleter=new QCompleter(completerList,this);
pCompleter->setCompletionMode(QCompleter::PopupCompletion);
pCompleter->setCaseSensitivity(Qt::Case Insensitive);
pCombobox->setCompleter(pCompleter);