Adding "Merge cells" support to the MFC GridControl

Download demo project - 303 Kb

Sample Image - gridcontrl.jpg

Sample Image - print.jpg

Introduction

This example demonstrates how to add "merge cells" ability to Chris Maunder's MFC Grid control (derived from CWnd).

The example modifies only two classes: CGridCellBase and CGridCtrl. In the class CGridCellBase ,the following four private member variables are added:

CCellRange m_MergeRange;
bool m_IsMergeWithOthers;
CCellID m_MergeCellID;
bool m_Hide;

Six public member functions are also added:

void UnMerge();
virtual bool IsShow() ;
virtual CCellRange GetMergeRange();
virtual bool IsMergeWithOthers();
virtual CCellID GetMergeCellID();
virtual void SetMergeCellID(CCellID cell);

In the class CGridCtrl, the following six public member functions are added:

CGridCellBase* GetCell(CCellID cell);
CCellID GetMergeCellID(CCellID cell);
void UnMergeSelectedCells();
void MergeSelectedCells();
void UnMergeCells(int nStartRow, int nStartCol, int nEndRow, int nEndCol);
void MergeCells(int nStartRow, int nStartCol, int nEndRow, int nEndCol);

Usage

Use CGridCtrl::MergeSelectedCells() and MergeCells() to merge the selected cells;
Use CGridCtrl::UnMergeSelectedCells() and UnMergeCells() to restore the selected cell to its original state.

History

1.7 fixed the bug when merging in the corner, by Luther Bruck - 2002/12/31
1.6 fixed the bug when resizing the merged row - 2002/11/20
1.5 fixed the bug when resizing the merged column - 2002/11/18
1.4 bug when printing merge cell across pages fixed - 2002/10/10
1.3 fixed cells merge added - 2002/9/27
1.2 print bug fixed - 2002/9/23
1.1 scroll bug fixed - 2002/9/18
1.0 first release - 2002/9/15

(Note that users of the Grid control are bound by Chris' copyright requirements detailed on his web page.)

License

This article has no explicit license attached to it but may contain usage terms in the article text or the download files themselves. If in doubt please contact the author via the discussion board below.

A list of licenses authors might use can be found here

About the Author

Huang Wei

Web Developer

China

Member

He got Master degree of Theory and Application of Automatic Control from Tsinghua university(Beijing,China) in 1997,from then on he has been working for Tsinghua TongFang Software Co.Ltd,Beijing China.

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Re: Problem deleting rows - FIXED!

andrewtruckle

3:01 9 Jun '06

The bug sniffer has been at work. Do this to avoid the problems:

Step 1:

In CGridCellBase operator= change:

SetMergeRange(cell.GetMergeRange());

	SetMergeRange(cell.GetMergeRange());
	m_bBaseForMerged = cell.IsBaseForMerged();

The bug in SetMergeRange is here:

void CGridCellBase::SetMergeRange(CCellRange range)

{

	m_MergeRange=range;

-->	m_bBaseForMerged = 1;   <---

}

It should not do that. It should be using the value of the cell being copied. Only true merged cells should have a base flag set.

Step 2:

In CGridCellBase InflateMergedRange change to:

void CGridCellBase::InflateMergedRange(int cx, int cy)
{
	if (IsMerged())
	{
		m_MergeRange.Set(
			m_MergeRange.GetMinRow() + cy,
			m_MergeRange.GetMinCol() + cx,
			m_MergeRange.GetMaxRow() + cy,
			m_MergeRange.GetMaxCol() + cx
			);
	}
	else if(IsMergeWithOthers())
	{
		m_MergeCellID.row += cy;
		m_MergeCellID.col += cx;
	}
}

The bug is that only the BASE base has a valid range object.
Likewise, only merged cells utilise a merged cell id object.

The merged cell id object was not getting updated, so the merged cells now pointed to the wrong master base cell.

Because we have now corrected the operator= call in step 1, we could use IsBaseForMerge instead of IsMerged. But this works using the existing method IsMerged.

Step 3:

In CGridCtrl::InflateMergedRanges change to:

void CGridCtrl::InflateMergedRanges(int nStartRow, int nStartCol, int cx, int cy)
{
	for(int i = nStartRow; i < GetRowCount(); i++)
	{
		for(int j = nStartCol; j < GetColumnCount(); j++)
		{
			if(GetCell(i, j)->IsMerged() || GetCell(i, j)->IsMergeWithOthers())
			{
				GetCell(i, j)->InflateMergedRange(cx, cy); 
			}
		}
	}
}

As described for step 2, you need to intercept and modify both base cell (with a merge range) and merged cells (with a merged cell id).

AutoSizeColumn problem

andrewtruckle

21:04 24 May '06

When you autosize a column, and the cell is merged and the master cell, the column ends up being resized and the grid can effectively double in width.

I did this to overcome the problem:

AutoSizeColumn:

for (int nRow = nStartRow; nRow <= nEndRow; nRow++)

    {

        CGridCellBase* pCell = GetCell(nRow, nCol);

		// AJT Avoid merged cells in calculations

        if (pCell && !pCell->IsMerged())

		{

            size = pCell->GetCellExtent(pDC);

 

			if (size.cx > nWidth)

				nWidth = size.cx;

		}

    }

Clicking on a merged cell and moving by keyboard to merged cell

andrewtruckle

21:49 23 May '06

I have some problems here. Can anyone help me solve them?

1. In order to set a merged set of cells as the focus cell, you must click on the "base" cell for the merged cells. You can't click on any of them.

2. Related to this (perhaps). My grid uses combo cells and the odd row of merged text cells. If I am on a combo cell and the move down a row using the cursor key, it renders the dropdown arrow of the hidden combo cell. This would explain why item 1 above does not let you click a none-based merged cell.

The question is how can I solve these two problems? It would be nice to click on any merged cell and it set the focus correctly and it would be nice when moving up/down etc. that it set the focus cell correctly.

Andrew

Re: Clicking on a merged cell and moving by keyboard to merged cell - Solution

andrewtruckle

23:24 23 May '06

What you have to do is not let the grid set focus to a cell that is merged with others. Add this code to SetFocusCell:

// EFW - Bug Fix - Force focus to be in a non-fixed cell

if (cell.row != -1 && cell.row < GetFixedRowCount())

  cell.row = GetFixedRowCount();

if (cell.col != -1 && cell.col < GetFixedColumnCount())

  cell.col = GetFixedColumnCount();

 

*** NEW CODE ***

// AJT Bug Fix

CGridCellBase	*pCell = NULL;

pCell = GetCell(cell);

if(pCell != NULL && pCell->IsMergeWithOthers())

  cell = pCell->GetMergeCellID();

Now, it will select the right cell and this works for mouse and cursor movements. It also avoids the rendering of grid lines.

Add MergeCell function with CGridCtrl2.25

MajorVon

22:09 11 Aug '05

Do you have the CGridCtrl with MergeCell function ?
Sign In·View Thread·Permalink	2.00/5 (1 vote)

Re: Add MergeCell function with CGridCtrl2.25

andrew.truckle@atkinsglobal.com

0:42 19 Sep '05

Can't the same instructions be followed in 2.25? Andrew
Sign In·View Thread·Permalink	2.33/5 (3 votes)

autosize merged cells?

markoot

10:19 28 Jul '05

Hi,
If i have text in cell (1,1) and i merged cells (1,1,1,7)
and when my text is too big for cell (1,1) AutoSize function resizes my (1,1) cells, but my text isn't too big for merged cells (1,1,1,7) (i mean there is a lot of place in whole row which is merged as one cells)$;
Better for me would be AutoSize also for merge cells.

Hmm, i will try to draw mky problem;
I have :
|______|_____|
|MyBigText___| <-this one is merged

After using AutoSize i have

|_________|_____|
|MyBigText______|
Column number 0 shouldn't be resized

// ___ means spacebar

Somebody helps me?
Thanks a lot.

//I hope i will be understood

df

I fixed the bug that it can't show the last line of grid.

victor_zhao

22:07 10 Jul '05

Using the grid control to print, you may see that the last line of the grid can't be show. After several hours of debuging, I found it will be OK only if you chang "white_rect.top=range.bottom + 1;" to "white_rect.top=range.bottom + 2;" in function--void CGridCtrl::OnPrint(CDC pDC, CPrintInfo pInfo), good lucky!
Sign In·View Thread·Permalink	2.00/5 (5 votes)

cannot downlaod the demo

manjuvk

19:35 9 Apr '05

Hi, can anyone send me the zip file. I cannot download it. Thanks & Regards Manju
Sign In·View Thread·Permalink	2.00/5 (1 vote)

Virtual Mode

TimPreuss

2:32 5 Jan '05

When I use the virtual mode and merge some cells, it seems that the callback-funktion never called again!?
Sign In·View Thread·Permalink	1.25/5 (5 votes)

word wrapping

andrew.truckle@atkinsglobal.com

3:47 7 Oct '04

What about simple word wrapping support for the grid control?
Sign In·View Thread·Permalink	1.50/5 (2 votes)

Re: word wrapping

Ice1374

5:45 21 May '06

m_pGridCtrl->SetItemFormat(2,0, DT_WORDBREAK);
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Re: word wrapping

andrewtruckle

8:14 21 May '06

I will have to try this. But my other concern is for when the grid is printed out. The widths of the columns need to be proportional to the printer so that what I see on screen is the same as the printer. I don't want it the other way round where the printer does what teh screen shows. This way I ensure it will fit on the printer one page wide.

Not sure how to accomplish that with a grid in a doc/view framework...

Can I have Tree Cells and merged cells on the same grid

Rafael Melo

9:45 13 Sep '04

Please if anyone knows how to make tree cells and merged cells works on the same grid tell me how. Thanks in advance, Rafael Melo
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How to print MFC GridControl ?

lzs

17:10 14 Aug '04

Firstly,thank Huang Wei for this usefull Merge Cells GridControl! Now I use several GridControls in a Document/View application, how can I print it? The gridCpntrol seems can only print one of them.
Sign In·View Thread·Permalink	1.33/5 (3 votes)

I can't download the source files.

TommyChoi

18:59 18 Jun '04

who can send me one? thanks! liuxing2001@hotmail.com
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2.25version

Darter

1:24 27 Apr '04

I aplly your modification to 2.25Version,It seem not work.
Sign In·View Thread·Permalink	2.00/5 (4 votes)

Re: 2.25version

igrzalja

4:33 30 Aug '04

Well it works for me. I added fix by shawkins (no border lines during selection). If somebody wants the code send me an email. Gezo
Sign In·View Thread·Permalink	2.00/5 (5 votes)

Re: 2.25version

andrew.truckle@atkinsglobal.com

0:46 19 Sep '05

I am looking for a 2.25 with any bugs fixed that include merge cells support. Can you email this to me please?
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Re: 2.25version

qz_yc_kj

3:37 13 Nov '05

I am looking for a 2.25 with any bugs fixed that include merge cells support. Can you email this to me please?
Sign In·View Thread·Permalink	2.00/5 (1 vote)

Re: 2.25version

homerhuang

17:42 21 Feb '06

I am looking for a 2.25 with any bugs fixed that include merge cells support. Can you email this to me please? homerhuang
Sign In·View Thread·Permalink	2.00/5 (2 votes)

Re: 2.25version

mikewolfli

22:32 25 Apr '06

I have modified it in 2.25 version as you doing in 2.24,and it works very well. Thank you very much for your working!
Sign In·View Thread·Permalink	1.00/5 (1 vote)

Problem with Scrolling

JIJESH.G

1:16 1 Mar '04

Use the Sample Application providd with the Grid View with Merge Cell Support. Scroll to the right so that part of the merged cell is only viewable. Then minimize and maximise the girdview(Gridvi1). The merged cell is shown in the background . What may be the problem Help?
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Re: Problem with Scrolling

Kiato L.

1:49 6 Aug '04

I had the same problem when I scrolled verticaly. The two bugs are identical so what I have done for my problem can be easily adapted for yours.

In the GridCtrl.cpp file, search for the OnDraw function. Then inside of this function, we have a part commented as :
// draw rest of non-fixed cells"

Inside this block of code, begining with



rect.bottom = nFixedRowHeight-1;

for (row = minVisibleRow; row <= maxVisibleRow; row++)

You will find the following line :



if(!pCell->IsMergeWithOthers())

Replace it by :



if(!pCell->IsMergeWithOthers() || row == minVisibleRow )

One of the next lines is :



pCell->Draw(pDC, row, col, rect, FALSE);

Replace it by :



if( row == minVisibleRow && pCell->IsMergeWithOthers())

   pCell->KLDraw(pDC, row, col, rect, FALSE);

else

   pCell->Draw(pDC, row, col, rect, FALSE);

Where KLDraw is exactly the same as the Draw function but without the lines :



if(m_Hide && !IsMerged())

{

  return TRUE;

}

That works for me and solve my problem with the vertical scroll and the resize of the grid.

Minimum changes should be made to solve the same problem with the horizontal croll.

Problem with printing merging cells in fixed columns

wlegierski

1:29 2 Dec '03

This is only informtation for those who have the same problem. I solve it by small changing function void CGridCtrl::PrintColumnHeadings(CDC pDC, CPrintInfo /pInfo/) Main loop I change from: for (int row = 0; row < GetFixedRowCount(); row++) to: for (int row = 0; row < GetRowCount(); row++) Maybe it isn't "neat" and it is worth to fix it in next version. Wojtek
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