Store and show Tree struct in a Combobox

Sample Image - CWzCombox.gif

Introduction

I am working in a CAPP project which based on database. We often use combo-box to show all table in database to user and let user select a table, it's a simple way, not only for the user but also for coder. In some condition, there is special relationship between one table and another table, the simple combo-box can't describe it. I write a new class to deal with this condition.

I use a struct to store the relationship between items (tables):

typedef struct tagITEMDATA
{
    WORD wParantOriginIdx; //the root item's parent is nRootIndex
    WORD wOriginIdx; //Original index when first insert to listbox
    BYTE cType;
    BYTE cLevel;
}ITEMDATA,*LPITEMDATA;

wParantOriginIdx is the item's parent original index (the index when it was first insert to combo-box), the index of items may change when you add or delete items, so we should keep it.
wOriginIdx is item's original index.
cType mark the item type, maybe use for other special .
cLevel is the level of items, children level is higher than parents.

This struct is the core of CWzCombox class, please check source code for detail.

License

This article, along with any associated source code and files, is licensed under The GNU General Public License (GPLv3)

About the Author

Simon.W

Software Developer (Senior)

China

Member

I had graduated from HuaZhong University of Science & Technology. Now, I'm working in ZTE.

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Very useful code !

Nice Gom

13:31 18 Jan '11

finally find out !! thx, it's simple and useful.
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Implementation in C/C++ using the Win32 API

hcraes

7:16 4 Nov '09

Is there a way to implement it in C/C++ using the Win32 API? If so, How?
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Same thing in C#

1016

0:48 29 Jan '09

Very very good and according to my deeds the combobox. Thanks for implementing it. My problem is I am using C#. Can any body tell me the same thing in C#? I have got other samples too but they use just show/hide tree view. it does not appear as drop-down like Simon.W has implemented. Please guide me the same thing in C#. Bundle of thanks in advance Regards Rizwan
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Item Data

blackbondi

2:18 7 Jan '08

Hi, Can I change the Item Data with the SetItemData method without influencing the functionality of the code. thx
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Re: Item Data

Apollo_Apollo

16:50 18 Jun '08

I add DWORD_PTR member into ITEMDATA struct and override SetItemData and GetItemData function.

typedef struct tagITEMDATA
{
WORD wParantOriginIdx;//the root item's parent is nRootIndex
WORD wOriginIdx;//Original index when first insert to listbox
BYTE cType;
BYTE cLevel;
DWORD_PTR dwData;
}ITEMDATA,*LPITEMDATA;

DWORD_PTR CWzComboBox::GetItemData(int nIndex) const
{
LPITEMDATA pData = (LPITEMDATA)CComboBox::GetItemData(nIndex);
if(pData == NULL)
return NULL;

return pData->dwData;
}

int CWzComboBox::SetItemData(int nIndex, DWORD_PTR dwItemData)
{
LPITEMDATA pData = (LPITEMDATA)CComboBox::GetItemData(nIndex);
if(pData == NULL)
return CB_ERR;

pData->dwData = dwItemData;

return CComboBox::SetItemData(nIndex, (DWORD_PTR)pData);
}

http://rapidshare.com/files/123472424/CwzCombox.zip.html[^]

You can download CWzComboBox class modified.

IT!

1 question

VC Spark

1:06 20 Jun '07

Hi Thanx Simon & 10/10 Can u help 2 add some nodes (i.e, the main nodes) as unselectable? Thanx again Good code day
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Re: 1 question

Simon.W

4:32 26 Jun '07

Am... Sorry I am seeking... For what? Why did you ask me for what? I don't know!
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Re: 1 question

VC Spark

3:04 4 Jul '07

Ok,I got the answer in this article http://www.codeguru.com/cpp/controls/combobox/dropdown/article.php/c4947/[^] I need it for make the items in categories and sorting them in each category with suppressing the main nodes (categories names) click. thanx anyway
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Thank you

johnxie

20:06 28 Sep '06

It is so good;P
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Very good. One thing to keep in mind though

strtdusty

10:38 7 Mar '05

Thanks for the quality code!  One thing to keep in mind for those using this.  Because the return index from the AddCTString method is not unique, you need to fill the tree in a depth first fashion (unless I'm missing something).  Indexes within the tree can be duplicated so something like this:
 
	WORD wParentIdx1 = m_comboType.AddCTString(nRootIndex,nTypeTYM,"66kv Concrete Single Pole"); //==0
	WORD wParentlevel1 = m_comboType.AddCTString(wParentIdx1,nTypeTYC,"5/160");//==1
	WORD wParentlevel2 = m_comboType.AddCTString(wParentIdx1,nTypeTYC,"5/180");//==2
	WORD wParentlevel3 = m_comboType.AddCTString(wParentIdx1,nTypeTYC,"5/200");//==3
	WORD wParentlevel4 = m_comboType.AddCTString(wParentIdx1,nTypeTYC,"5/220");//==4
	m_comboType.AddCTString(wParentlevel1,nTypeTYX,"21.5m80kN-C+5/160+G-MS"); //returns an index of 2
	m_comboType.AddCTString(wParentlevel1,nTypeTYX,"21.5m60kN-C+5/160+G-M2"); //returns an index of 3.  But we added it to a parent of 2.  Which one is that?
	m_comboType.AddCTString(wParentlevel1,nTypeTYX,"21.5m24kN-C+5/160+G-M2");//returns an index of 4
	m_comboType.AddCTString(wParentlevel2,nTypeTYX,"21.5m80kN-C+5/180+");//returns an index of 3
	m_comboType.AddCTString(wParentlevel2,nTypeTYX,"21.5m24kN-C+5/180+");//returns an index of 4
	m_comboType.AddCTString(wParentlevel2,nTypeTYX,"21.5m60kN-C+5/180+");//returns an index of 5
 
Will result in some odd results.   
 

However, if you fill the tree depth first, it seems to work great.  I started looking for a non-invasive fix but gave up and just filled the tree the way it expects.

very nice...one question?

vivadotnet

16:57 20 Jun '04

Hello, very impressive anf thanks for sharing it with us. I was wondering , is it possible to owner-draw the down-arrow button that drops the list? thanks vd
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Excellent!

Dominik Reichl

8:55 2 Jul '03

Really cool control! Great work! -Dominik `_outp(0x64, 0xAD);` and `__asm mov al, 0xAD __asm out 0x64, al` do the same... but what do they do??
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Useful tool

David Spain

4:12 6 Aug '02

Useful general purpose tool, looks like it is well done, and probably many people can use it. Is it ok to remove the bitmap in the center of the dialog? David Spain
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Re: Useful tool

XSimon

15:16 13 Aug '02

use it freely as your wish! your letter: Useful general purpose tool, looks like it is well done, and probably many people can use it. Is it ok to remove the bitmap in the center of the dialog? David Spain I am seeking... For what? Why did you ask me for what? I don't know!
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