Qhash封装之后内存释放问题,求教~

因为工程需要,对QHash进行封装,封装之后,进行Delete,但是内存并不释放,单独对QHash进行测试,发现没有问题,贴出代码,请教各位大神,看看那是哪里的问题~~~~~~
头文件如下:
#ifndef SETTABLE_H
#define SETTABLE_H
#include<QHash>
#include "settings.h"
#include<QHashIterator>
#include<QMutex>
#include"systemlog.h"
#include "gloabletime.h"
class SetTable
{
public:
SetTable();
~SetTable();
//COPY CONSTRUCTURE
SetTable(const SetTable& s);
SetTable& operator = (const SetTable& ); //赋值符重载

bool Add(QString Name ,Settings* Value);
bool Remove(QString Name);
Settings* GetItem(QString Name);

QString GetItemByEquipID(QString EquipID);
QString GetItemByEquipID(QString EquipType,QString EquipAddress);
bool SetItem(QString ClassName,Settings* Value);
bool SetItem(QString ClassName,QString SubClassName,QString OptionName,QString Value );
QHash<QString,Settings*>::const_iterator GetIterator();
void ReleaseResource();
int Count();
private:
QHash<QString,Settings*>*StList;// modify by pointer
};

#endif // SETTABLE_H
构造,析构,copy构造 实现如下:
SetTable::SetTable()
{
this->StList=new QHash<QString,Settings*>();
}
SetTable::~SetTable()
{
this->StList->clear();
this->StList->squeeze();
this->StList->detach();
this->StList->~QHash();
delete this->StList;
StList=NULL;
}

SetTable::SetTable(const SetTable& s)
{
this->StList=new QHash<QString,Settings*>;
* this->StList=*s.StList;
}
SetTable& SetTable::operator =(const SetTable& s)
{
if(this==&s)
{
return *this;
}
else
{
* this->StList=*s.StList;
return *this;
}
}
求指教,求解惑,求答疑~~~~~~~~~~