[英]QT, C++, cannot call member function without object
在我的mainwindow.cpp中是進行調用的地方。 應該在按鈕單擊事件上發生呼叫。 錯誤提示cannot call member function 'void Foo::setFooAttributes(A&, B&, C&, D&)' without object
。
void MainWindow::on_generateButton_clicked()
{
setCreator(ui->interfaceCreatorName->text());
setAlternateName(ui->interfaceAlternateName->text());
setDomain(ui->interfaceDomain->text().toInt());
QString filename = getCreator() + "'s " + getAlternateName() + ".txt";
QFile file( filename );
A a; B b; C c; D d;
Foo::setFooAttributes(a,b,c,d); //ERROR: cannot call member function without object
generateTop(file);
generateMiddle(file);
generateSecondaryMid(file);
generateLast(file);
generateTertiaryMid(file, a, b, c, d);
}
該函數本身如下所示:
void Foo::setFooAttributes(A &aFoo, B &bFoo, C &cFoo, D &dFoo){
aFoo.stopPoint = MainWindow.ui->aInterfaceStopPoint->text().toDouble();
aFoo.rate = MainWindow.ui->aInterfaceRate->text().toInt();
aFoo.domain = MainWindow.ui->aInterfaceDomain->text().toInt();
aFoo.length = MainWindow.ui->aInterfaceLength->text().toInt();
bFoo.stopPoint = MainWindow.ui->bInterfaceStopPoint->text().toDouble();
bFoo.rate = MainWindow.ui->bInterfaceRate->text().toInt();
bFoo.domain = MainWindow.ui->bInterfaceDomain->text().toInt();
bFoo.length = MainWindow.ui->bInterfaceLength->text().toInt();
cFoo.stopPoint = MainWindow.ui->cInterfaceStopPoint->text().toDouble();
cFoo.rate = MainWindow.ui->cInterfaceRate->text().toInt();
cFoo.domain = MainWindow.ui->cInterfaceDomain->text().toInt();
cFoo.length = MainWindow.ui->cInterfaceLength->text().toInt();
dFoo.stopPoint = MainWindow.ui->dInterfaceStopPoint->text().toDouble();
dFoo.rate = MainWindow.ui->dInterfaceRate->text().toInt();
dFoo.domain = MainWindow.ui->dInterfaceDomain->text().toInt();
dFoo.length = MainWindow.ui->dInterfaceLength->text().toInt();
}
我將包括foo.h在內的其余代碼粘貼到此處pastebin源代碼中
我首先嘗試調用setFooAttributes(a,b,c,d);
沒有Foo::
但是給了我這樣'setFooAttributes' was not declared in this scope
錯誤,例如'setFooAttributes' was not declared in this scope
讓你Foo::setFooAttributes
一個static
成員函數,因為它並不在“此”實例進行操作。
在使用它時,如果A / B / C / D實際上是同一類型(或常見類型的子類型),則可以考慮刪除所有重復項,以便更好地遵循DRY(不要重復自己)原理:
template <typename A> static void Foo::setFooAttributes(Foo &aFoo, int iface) {
aFoo.stopPoint = MainWindow.ui->interfaceStopPoint[iface]->text().toDouble();
aFoo.rate = MainWindow.ui->interfaceRate[iface]->text().toInt();
aFoo.domain = MainWindow.ui->interfaceDomain[iface]->text().toInt();
aFoo.length = MainWindow.ui->interfaceLength[iface]->text().toInt();
}
static void Foo::setFooAttributes(Foo &aFoo, Foo &bFoo, Foo &cFoo, Foo &dFoo) {
setFooAttributes(aFoo, 0);
setFooAttributes(bFoo, 1);
setFooAttributes(cFoo, 2);
setFooAttributes(dFoo, 3);
}
(這需要您轉換{a,b,c,d}InterfaceStopPoint
, {a,b,c,d}InterfaceRate
, {a,b,c,d}InterfaceDomain
和{a,b,c,d}InterfaceLength
進入數組,而不是四個單獨的變量)。
你甚至可以通過使用循環或可變參數數量模板函數這一提高,但我會離開,作為一個練習。
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