Q3ValueList Problem

[batileon]

While porting code from QT3 to QT4, I found that my program terminated unexpectedly, and the screen shows the following line:

ASSERT: "i < this->size()" in file /usr/local/Trolltech/Qt-4.4.0/include/Qt/q3valuelist.h, line 201

actually the program is running the following line:

Q3ValueListIterator <TransactionHistory> itr = m_transaction_history.at( sequenceNo );

Q3ValueListIterator <TransactionHistory> itr = m_transaction_history.at( sequenceNo );

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where

Q3ValueList <TransactionHistory> m_transaction_history;
        int sequenceNo;

Q3ValueList <TransactionHistory> m_transaction_history;
        int sequenceNo;

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and "TransactionHistory" is a self defined class which hold some int values

after dumping the details, I found that the size of m_transaction_history is 0 and sequenceNo is 0 too.
In previous version(QT3), the line work fine......

Can anyone tell me what's happening and how can I solve this?

[maverick_pol]

Where do you assign data to these variables:

Q3ValueList <TransactionHistory> m_transaction_history;
 int sequenceNo;

Q3ValueList <TransactionHistory> m_transaction_history;
 int sequenceNo;

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and/or fill the q3valuelist with data ?