当你在Qt开发中遇到error C2338: qobject_cast requires the type to have a Q_OBJECT macro这个编译错误时,这通常意味着你试图使用qobject_cast来转换一个并不包含Q_OBJECT宏的类。为了解决这个问题,你可以按照以下步骤进行: 1. 理解错误信息的含义 qobject_cast是Qt中用于在运行时安全地将一个QObject指针(或...
error:staticassertion failed: qobject_castrequiresthe type to have a Q_OBJECT macro Run Code Online (Sandbox Code Playgroud) 我不太确定这里有什么问题,这些都是 Qt 内置类型,所以我做错了什么? 2 您必须将 Q_OBJECT 放入类定义中,如下所示: classMyClass:publicQObject { Q_OBJECT// ^^^public: M...
Unlike qobject_cast, inherits() accepts a char* type name instead of a type expression. This operation is slower than qobject_cast because it requires an extra hashtable lookup, but it can be useful if you need input-driven type checking. Example 15.2 shows some client code that uses inhe...
T qobject_cast(const QObject *object) Returns the given object cast to type T if the object is of type T (or of a subclass); otherwise returns 0. If object is 0 then it will also return 0. The class T must inherit (directly or indirectly) QObject and be declared with the Q_OBJ...
The convenience function isWidgetType() returns whether an object is actually a widget. It is much faster than qobject_cast<QWidget *>(obj) or obj->inherits("QWidget"). Some QObject functions, e.g. children(), return a QObjectList. QObjectList is a typedef for QList<QObject *>. ...
The convenience function isWidgetType() returns whether an object is actually a widget. It is much faster than \l{qobject_cast()}{qobject_cast}<QWidget *>(\e{obj}) or \e{obj}->\l{inherits()}{inherits}("QWidget"). Some QObject functions, e.g. children(), return a QObjectList...