use custom mimedata between two windows

[prasad_N]

HI,
I wanted to drag & drop custom mime data between two windows (basically 2 QTreeview's in the same application), But when I use this custom mimedata I am not able to drop any data (I could see + sign while dragging in 1st window & the moment I leave the 1st winnow the + sign is changing to ForbiddenCursor & I am not able to drop data in 2nd window)

My classs:

class MyMimedata : public QMimeData
{
    Q_OBJECT
public:
    MyMimedata () : QMimeData()  { }
 
    bool hasFormat(const QString &mimetype) const { return QMimeData::hasFormat(mimetype); }
    QStringList formats() const{ return QMimeData::formats(); }
    QVariant retrieveData(const QString &mimetype, QVariant::Type preferredType) const { QMimeData::retrieveData(mimetype, preferredType); }
};

class MyMimedata : public QMimeData
{
    Q_OBJECT
public:
    MyMimedata () : QMimeData()  { }

    bool hasFormat(const QString &mimetype) const { return QMimeData::hasFormat(mimetype); }
    QStringList formats() const{ return QMimeData::formats(); }
    QVariant retrieveData(const QString &mimetype, QVariant::Type preferredType) const { QMimeData::retrieveData(mimetype, preferredType); }
};

To copy to clipboard, switch view to plain text mode 

I am not able to drag & drop above custome data type.
When I use

Q_DECLARE_METATYPE(MyMimedata );

Q_DECLARE_METATYPE(MyMimedata );

To copy to clipboard, switch view to plain text mode 

I am getting compile time error: 'QMimeData::QMimeData(const QMimeData&)' is private

What am I doing wrong here.... any hint ??