我将lambdas连接到QObject的信号:
QObject::connect(handle,&BatchHandle::progressMax,[this](const ProcessHandle* const self,const int value) { this->maxProgress(value); });
上面的代码编译没有问题.
但是Qt :: QueuedConnection是绝对必要的,因为句柄对象最终将移动到另一个线程.
QObject::connect(handle,&BatchHandle::finished,[this](const ProcessHandle* const self) { this->processIsRunning(false); },(Qt::ConnectionType)Qt::QueuedConnection);
请注意我是如何添加显式强制转换以确保它正确标识值类型的.结果:
1>src\TechAdminServices\database\techCore\processes\import\ImportManagerDialog.cpp(191): error C2664: 'QMetaObject::Connection QObject::connect<void(__cdecl taservices::ProcessHandle::* )(const taservices::ProcessHandle *),Qt::ConnectionType>(const taservices::ProcessHandle *,Func1,const QObject *,Func2,Qt::ConnectionType)' : cannot convert parameter 3 from 'taservices::`anonymous-namespace'::<lambda58>' to 'const QObject *' 1> with 1> [ 1> Func1=void (__cdecl taservices::ProcessHandle::* )(const taservices::ProcessHandle *),1> Func2=Qt::ConnectionType 1> ] 1> No user-defined-conversion operator available that can perform this conversion,or the operator cannot be called
连接lambda时如何获得排队连接?
解决方法
我认为你需要使用
QObject::connect
overload,它允许你指定应该调用lambda的上下文…
QObject::connect( handle,target_context,/* Target context parameter. */ [this](const ProcessHandle* const self,const int value) { this->maxProgress(value); },Qt::QueuedConnection);