Comparing QVariant::Type with custom registered types

[sykac]

Hello,

I'm trying to implement a conversion function which looks like this:

CustomDataType conversionFunc(QVariant::Type type)
{
    switch (type) {
    case QVariant::Int: return CustomDataType::C_INT;
    case QVariant::Double: return CustomDataType::C_DOUBLE;
    .
    .
    .
    default: return CustomDataType::C_INVALID;
    }
}

This works fine if I don't use non Qt data types in QVariant. I would like to add a new case e.g.:

case QVariant::Eigen::Vector3d: return CustomDataType::C_VEC3D;

This won't build although I registered the type with Q_DECLARE_METATYPE(Eigen::Vector3d). Is something like this possible? If so, how? I can still compare QVariant::typeName(), but isn't there some way of doing this using enums like in the code above?

[VRonin]

https://doc.qt.io/qt-5/qvariant.html#userType

[kshegunov]

@sykac said in Comparing QVariant::Type with custom registered types:

I registered the type with Q_DECLARE_METATYPE(Eigen::Vector3d).

Why do you want to do that in the first place? What's the point of having an eigen vector in a QVariant?

[sykac]

@kshegunov I'm using it in a generic interface - one method for passing multiple datatypes in one argument.

@VRonin Thanks, that's what I needed.

[VRonin]

@sykac said in Comparing QVariant::Type with custom registered types:

one method for passing multiple datatypes in one argument

Looks like you really want a template method instead