Question

在我的mainwindow.cpp中进行调用。调用应该发生在按钮点击事件上。错误说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);

}

该功能本身如下：

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();

}

我将其余代码（包括foo.h）粘贴到此处pastebin source

我首先尝试在没有setFooAttributes(a,b,c,d);的情况下调用Foo::，但这给了我'setFooAttributes' was not declared in this scope

这样的错误

Answer 1

将Foo::setFooAttributes成为static成员函数，因为它不会在＆＃34;这个＆＃34;实例

如果您对此感兴趣，如果A / B / C / D实际上是同一类型（或普通类型的子类型），您可以考虑删除所有重复项，以便更好地遵循DRY（Don＆＃39; t重复自己）原则：

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);
}

（这需要您将{a,b,c,d}InterfaceStopPoint，{a,b,c,d}InterfaceRate，{a,b,c,d}InterfaceDomain和{a,b,c,d}InterfaceLength中的每一个转换为数组，而不是四个单独的变量。

你甚至可以通过使用循环或变量模板函数来改进这一点，但我会将其作为练习。

QT，C ++，无法在没有对象的情况下调用成员函数

1 个答案: