List Control Column Widths

[OneSource]

Hi and thanks for reading.

As with most things in VC++ (as it seems to me), something simple takes forever to figure out. Here's the deal. I have a list control with 3 columns. I want to size the columns based on the total width of the list control and not on hard-coded values. Here's my code:

	CRect		rListViewWidth;
	LV_COLUMN	listColumn;
	int          nColumn = 0;
	char*		arColumns[3] = {"One", "Two", "Three"};	

	// Set up the list control.
	listColumn.mask = LVCF_FMT|LVCF_WIDTH|LVCF_TEXT|LVCF_SUBITEM;
	listColumn.fmt = LVCFMT_LEFT;
	::SendMessage(m_listCtrl.m_hWnd, LVM_SETEXTENDEDLISTVIEWSTYLE,
				  LVS_EX_FULLROWSELECT, LVS_EX_FULLROWSELECT);

	m_listCtrl.GetWindowRect(&rListViewWidth);
	int nWidth = rListViewWidth.Width();

	// Add the column headers to the list view.
	for( nColumn = 0; nColumn < 3; nColumn++ )
	{
		listColumn.iSubItem = nColumn;
		listColumn.pszText = arColumns[nColumn];

		// Size the columns.
		if(nColumn == 0) // One
			listColumn.cx = (nWidth * 20 / 100);
		else if(nColumn == 1) // Two
			listColumn.cx = (nWidth * 37 / 100);
		else if(nColumn == 2) // Three
			listColumn.cx = (nWidth * 42 / 100);

		m_listCtrl.InsertColumn(nColumn, &listColumn);
	}[code]

I put in the (nWidth * x / 100) to avoid compiler warnings about converting from double to int. Anyway, I know this is simple, but I've already spent too much time trying to figure it out. Can someone tell me how to do this? 

Thanks, 

OneSource

 

[palbano]

After you insert all the columns iterate though them again and for each one use CListCtrl::SetColumnWidth()

-pete

 

[OneSource]

Palbano,

Thanks for your response .... it got me closer to a solution because now the columns can be sized independently. But there is still a piece of the puzzle missing. I want to size the columns based on the width of the list control. I don't know how to get the width. Here's how my code looks now:

	m_listCtrl.GetWindowRect(&rListViewWidth);
	ScreenToClient(&rListViewWidth);
	int nWidth = rListViewWidth.Width();

	// Add the column headers to the list view.
	for( nColumn = 0; nColumn < 3; nColumn++ )
	{
		listColumn.iSubItem = nColumn;
		listColumn.pszText = arColumns[nColumn];
		listColumn.cx = 10;
		m_listCtrl.InsertColumn(nColumn, &listColumn);
	}

	for( nColumn = 0; nColumn < 3; nColumn++ )
	{
		// Size the columns.
		if(nColumn == 0) // One
			m_listCtrl.SetColumnWidth(nColumn, (nWidth * 20 / 100));
		else if(nColumn == 1) // Two
			m_listCtrl.SetColumnWidth(nColumn, (nWidth * 37 / 100));
		else if(nColumn == 2) // Three
			m_listCtrl.SetColumnWidth(nColumn, (nWidth * 42 / 100));
	}

How do I get the width of the list control into nWidth? Example code would be great!

 

[palbano]

what you have should work fine.

>> m_listCtrl.GetWindowRect(&rListViewWidth);

you don't need screentoclient since you only care about the width that won't change. If you use GetClientRect() there might be a few pixel difference.

Have you looked at the value of nWidth? Does it look correct? If so I believe your problem is in your algebra formula

(nWidth * 42 / 100)

you have not applied the distributive property to the formula. I think you want (nWidth * (42 / 100))

-pete

 

[apatterno]

OneSource,
Also keep in mind that your list control may have a scrool bar at the right, which will decrease the width of your control. So a more accurate code to find the width of the list control would be
[tt]
const int maxitems = /* number of items that fit w/o scrolling */

int cx; // width
RECT clientRect;
m_ctlList.GetClientRect(&clientRect);
cx = clientRect.right - clientRect.left;

if (m_ctlList.GetCount() > maxitems) {
cx -= ::GetSystemMetrics(SM_CXVSCROLL);
}
[/tt]

 

[OneSource]

palbano and apatterno, thanks for your replies. I was able to get it to work. The problem I was having was due to some font manipulation that I was doing on the property sheet that contained the list control. I tried my code in a project from scratch and everything worked just fine.

FYI, the problem wasn't the distributive property formula because the following statements always produce the same results: (nWidth * 42 / 100) and (nWidth * (42 / 100)).

Also, I didn't need to use m_listCtrl.SetColumnWidth because listColumn.cx = 10 did the trick.

I do have another question about all this. I'll ask it in a new post ....

Thanks again,

OneSource