[英]std::ostream to QString?
Is there a way to convert an std::ostream to a QString? 有没有办法将std :: ostream转换为QString?
Allow me to expand in case it is useful: I am writing a program in C++/Qt and I used to (not) deal with / debug exceptions by just using std::cout, as in for example: 允许我扩展,以防它有用:我正在用C ++ / Qt编写一个程序,我曾经(不)通过使用std :: cout来处理/调试异常,例如:
std::cout << "Error in void Cat::eat(const Bird &bird): bird has negative weight" << std::endl;
Now I want to throw errors as QStrings and catch them later, so I would now write instead: 现在我想把错误作为QStrings抛出并稍后捕获它们,所以我现在写了:
throw(QString("Error in void Cat::eat(const Bird &bird): bird has negative weight"));
My issue is that I've been overloading the operator << so that I can use it with many objects, for instance a Bird
, so I would actually have written: 我的问题是我一直在重载运算符<<以便我可以将它与许多对象一起使用,例如
Bird
,所以我实际上写了:
std::cout << "Error in void Cat::eat(const Bird &bird): bird " << bird << " has negative weight" << std::endl;
Is there a way that I can throw this as a QString now? 有没有办法可以把它作为QString抛出? I would like to be able to write something like:
我希望能够写出如下内容:
std::ostream out;
out << "Error in void Cat::eat(const Bird &bird): bird " << bird << " has negative weight" << std::endl;
throw(QString(out));
but that doesn't work. 但这不起作用。 What should I do?
我该怎么办?
You can use an std::stringstream
as follows: 您可以使用
std::stringstream
,如下所示:
std::stringstream out;
// ^^^^^^
out << "Error in void Cat::eat(const Bird &bird): bird " << bird << " has negative weight" << std::endl;
throw(QString::fromStdString(out.str()));
// ^^^^^^^^^^^^^^^^^^^^^^^^^^
Specifically, the std::stringstream::str
member function will get you an std::string
, which you can then pass to the QString::fromStdString
static member function to create a QString
. 具体来说,
std::stringstream::str
成员函数将为您提供一个std::string
,然后您可以将其传递给QString::fromStdString
静态成员函数以创建QString
。
The std::stringstream
class can receive input from overloaded <<
operators. std::stringstream
类可以从重载的<<
运算符接收输入。 Using this, combined with its ability to pass its value as a std::string
, you can write 使用它,结合它将其值作为
std::string
传递的能力,你可以写
#include <sstream>
#include <QtCore/QString>
int main() {
int value=2;
std::stringstream myError;
myError << "Here is the beginning error text, and a Bird: " << value;
throw(QString::fromStdString(myError.str()));
}
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