C / C++ / MFC

15-Sep-05 8:29

I'm having a bit of a problem getting the handle to my listview. Can anyone suggest how I would pass this so that I can get the listview text and compare?

Thanks

Tom Wright
tawright915@yahoo.com

ClockDivider15-Sep-05 9:11

15-Sep-05 9:11

I am not that experienced but as far as i know you have to pass a callback funtion as parameter:

i have done it useing mfc so zou have to translate that somewhat, this is the member function i declared as member of my derived listview, this example is used to sort numeric columns:

static int CALLBACK CallbackSortNumeric(LPARAM lParam1, LPARAM lParam2, LPARAM lParamSort);

Then, when you add a column, you have to pass the adress of the function (PFNLVCOMPARE pCALLBACKSORT):

this->InsertColumn(nCol, cHead,pCALLBACKSORT,iSortMode,iFormat, nWidth,nSubItem);

This way the sorting is managed in CallBackSortNumeric.

Hope it helps...

Martin...

Tom Wright15-Sep-05 10:06

15-Sep-05 10:06

ClockDivider wrote:
I am not that experienced but as far as i know you have to pass a callback funtion as parameter:

Yeah I did that. My problem is that in my callback I need to access the window handle and I cannot. I get a compiler error:
illegal reference to data member 'FileTransfer::hWnd' in a static member function

Here is my callback code:

<br />
int CALLBACK FileTransfer::ListViewCompareProc(LPARAM lParam1, LPARAM lParam2, LPARAM lParamSort)<br />
{<br />
	static LV_FINDINFO fi;<br />
	static int		 nItem1, nItem2;<br />
	static char		szBuf1[30], szBuf2[30];<br />
<br />
	// Determine the items that we are comparing.<br />
	//...........................................<br />
	fi.flags = LVFI_PARAM;<br />
	fi.lParam = lParam1;<br />
	<br />
	nItem1 = ListView_FindItem(hWnd, -1, &fi);<br />
 <br />
	fi.lParam = lParam2;<br />
	//nItem2 = ListView_FindItem(hWnd, -1, &fi);<br />
<br />
<br />
	return 0;<br />
}<br />

Thanks

Tom Wright
tawright915@yahoo.com

ClockDivider15-Sep-05 10:40

15-Sep-05 10:40

I am not sure why Smile | :)

but here is some code i have in my function that might belong to the problem:

int CALLBACK CListCtrlEx::CallbackSortString(LPARAM lParam1, LPARAM lParam2, LPARAM lParamSort)
{
// lParamSort contains a pointer to the list view control.
CListCtrlEx* pListCtrl = (CListCtrlEx*) lParamSort;
}

Thus you should be able to convert lParamSort to a CWnd* which then provides the propper m_hWnd

Is that true?

Tom Wright15-Sep-05 11:30

15-Sep-05 11:30

The problem with this is that I'm not using any MFC.

Here is my event code:

<br />
LPNMLISTVIEW lpNmlv = (LPNMLISTVIEW) lParam;<br />
<br />
			case LVN_COLUMNCLICK:<br />
				if (lpNmlv->hdr.hwndFrom == GetDlgItem(hWnd, IDC_LOCAL_FILELIST))<br />
				{<br />
					ListView_SortItems(lpNmlv->hdr.hwndFrom, ListViewCompareProc,(LPARAM)(lpNmlv));<br />
				}<br />
<br />
				if (lpNmlv->hdr.hwndFrom == GetDlgItem(hWnd, IDC_REMOTE_FILELIST))<br />
				{<br />
					HWND RemoteHwnd = GetDlgItem(hWnd, IDC_REMOTE_FILELIST);<br />
				}<br />
				return TRUE;<br />
<br />
<br />
int CALLBACK FileTransfer::ListViewCompareProc(LPARAM lParam1, LPARAM lParam2, LPARAM lParamSort)<br />
{<br />
	static LV_FINDINFO fi;<br />
	static int		 nItem1, nItem2;<br />
	static char		szBuf1[30], szBuf2[30];<br />
	NMLISTVIEW *lpNmlv = (NMLISTVIEW*)lParamSort;<br />
<br />
	// Determine the items that we are comparing.<br />
	//...........................................<br />
	fi.flags = LVFI_PARAM;<br />
	fi.lParam = lParam1;<br />
	<br />
	nItem1 = ListView_FindItem(lpNmlv->hdr.hwndFrom, -1, &fi);<br />
 <br />
	fi.lParam = lParam2;<br />
	nItem2 = ListView_FindItem(lpNmlv->hdr.hwndFrom, -1, &fi);<br />
	// Retrieve the item text so we can compare it.<br />
	//.............................................<br />
	ListView_GetItemText(lpNmlv->hdr.hwndFrom, nItem1, lParamSort, szBuf1, sizeof(szBuf1));<br />
	ListView_GetItemText(lpNmlv->hdr.hwndFrom, nItem2, lParamSort, szBuf2, sizeof(szBuf2));<br />
 <br />
	// Return the comparison results.<br />
	//...............................<br />
	if (lpNmlv) // ACENDING ORDER<br />
		return(strcmp(szBuf1, szBuf2));<br />
	else<br />
		return(strcmp(szBuf1, szBuf2) * -1);<br />
<br />
}<br />

Thanks

Tom Wright
tawright915@yahoo.com

ClockDivider15-Sep-05 12:14

15-Sep-05 12:14

Ummm... Your code compiles here...

But you already changed the calling of the ListView_FindItem and ListView_GetItemText, now using the lpNmlv.>hdr.hwndFrom, no?

What is the exact compiler error?

Tom Wright15-Sep-05 12:34

15-Sep-05 12:34

Yeah it compiles fine now. Just still not getting anything. I think I'm not setting my pointers correctly or the NMLISTVIEW struct.

You know there aren't very many samples of how to use this out there on the internet. Must be used much.

Tom Wright
tawright915@yahoo.com

ClockDivider15-Sep-05 13:49

15-Sep-05 13:49

The prob is this in:

ListView_GetItemText(lpNmlv->hdr.hwndFrom, lParam2, lParamSort, szBuf2, sizeof(szBuf2));

the parameter lParamsort is wrong here, it should define the column (lpNmlv->iSubItem).

AND: Do you to set the LPARAM value when inserting your item?

Here is an excerpt from .NET help: "The lParam1 parameter is the 32-bit value associated with the first item being compared, and the lParam2 parameter is the value associated with the second item. These are the values specified in the lParam member of the items’ LVITEM structure when they were inserted into the list."

I hade precisely the same problems as you, now that I assured being the item.lPram member valid and changing the wrong parameter value to the item.iSubitem it works...

Hope it helps now?...

Graham Bradshaw15-Sep-05 13:43

Graham Bradshaw

15-Sep-05 13:43

Tom Wright wrote:
My problem is that in my callback I need to access the window handle and I cannot

That's what the lParamSort paramter is for. You pass in whatever you want (for examnple, a number or a pointer to a data structure), and the same value is passed to your comparison function. Your comparision function can then interpret that lParam in the right way (as a number or dereference the pointer to get the data structure again), and process it.