Problem with the reference to (CTreeCtrlEx)

I have an MFC dialog which has a Tree(CTreeCtrlEx) structure where each node is a combo box.
I want to have a "Cancel" button which will cancel the option chosen by the user and goes with
the user chosen previosly.I have a cancel button but,as soon as the user changes the (CTreeCtrlEx)
item,the values will be changed.

Now all i want is to store the previous option and compared to DoModal return.and use the oprions
accordingly.

Currently, i am doing like this ,i have mentioned below
OC_Dlg_PureMFC_Test_Options_c is a subclass of CTreeCtrlEx

Code:

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OC_Dlg_PureMFC_Test_Options_c(m_Options).DoModal();  // m_Options is a reference...

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How will i save the previous m_Options?....Any idea?
I tried doing the following ...

Code:

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OC_TestOptions_Common_c *temp = new OC_TestOptions_Common_c(m_Options);
OC_Dlg_PureMFC_Test_Options_c(m_Options).DoModal();  // m_Options is a reference...

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But i dont know how to turn it back to m_Options... can any one help me??

You would have to write an == (are these equal?) and = (make these equal) operator in/for the CTreeCtrlEx derived class.

The == operator would run thru each node checking it exists and the text matches. It would return false (zero) as soon as it finds a difference.

The = operator would run thru each node adding or updating the node (if required).


Another, possibly easier, way is to store the TVITEM of the last edited node. This could be done within a derived CTreeCtrlEx class.

Once the user has decided to edit a node (but before the combo is created) save the TVITEM info in a member variable .

Code:

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//in header
TVITEM    m_tvItem; // holds last edited TV node

void CMyTreeCtrlEx::OnBeginLabelEdit (NMHDR* pNMHDR, LRESULT* pResult)
{
        NMTVDISPINFO *ptvDispInfo = (NMTVDISPINFO *)pNMHDR;
        CopyMemory(&m_tvItem, &ptvDispInfo->item, sizeof(TV_ITEM)); //copy the item being edited
        return CTreeCtrlEx::OnBeginLabelEdit(pNMHDR,pResult); //call the default processing
}

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Then write a method in the derived CTreeCtrlEx to find this node and reset the text (called if the cancel button is pressed).

Thanks for the reply...
But i want to save the m_Options itself which would be a better solution... How to do that??


Can i do anything with the help of DoDataExchange???


or like this

Code:

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a_Options=m_Options;
          OC_TestOptions_Common_c *temp = &m_Options;
      if( OC_Dlg_PureMFC_Test_Options_c(m_Options).DoModal() != IDOK)
          {
                        m_Options = (OC_TestOptions_Common_c&)temp;
          }

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But all these giving RUNTIME EXCEPTION.... Or compile time error


please help....

thanks

I need more info....

These are custom classes, so I do not know what functionality is coded into them (what they do, how they interact).

Nor do i know how complex they are, nor the process required to change them, etc.

But will have a guess....



You need a 'copy' (instance) of the 'OC_TestOptions_Common_c' class, not a pointer.
A pointer to 'm_Options' will change when the user edits the 'm_Options'.

Code:

---

OC_TestOptions_Common_c TempOptions;

TempOptions= &m_Options;//this will only work if the OC_TestOptions_Common_c class has an 'equals operator' method

//show the user the treeview of options
if( OC_Dlg_PureMFC_Test_Options_c(m_Options).DoModal() != IDOK)
{
      m_Options =TempOptions;
}

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I can see m_Options is an object of the class 'OC_TestOptions_Common_c'.

Does the 'OC_TestOptions_Common_c' class have a equals operator method?
[many standard classes (ie CString) have operators, your class may not have one]

something like

Code:

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//in header
public:
OC_TestOptions_Common_c operator=(OC_TestOptions_Common_c &Options);

//in class
OC_TestOptions_Common_c OC_TestOptions_Common_c::operator =(OC_TestOptions_Common_c &Options)
{
      //set all the members of 'this' to the one we have been passed ('Options')
      //any members that are derived classes will need their own equals operator
      m_Option=Options.m_Option;
      m_SomeOtherOption=Options.SomeOtherOption;
      etc....
}

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