Advanced MFC Programming

Chapter 14. Views
memset(&lvfi, 0, sizeof(LV_FINDINFO));
lvfi.flags|=LVFI_PARAM;
lvfi.lParam=lParam;
}
return lc.FindItem(&lvfi);
Here a LV_FINDINFO type object is stuffed, with LVFI_PARAM bit of member flags set to “1” and the
item parameter assigned to member lParam. Then the object is passed to function CListCtrl::
FindItem(…) to search the item in the list control. Function CExplorerView::FindItem(…)’s second
parameter is a CListCtrl type reference, this is because within static member function, we must use the
instance of an object to call any of its non-static functions. This function returns the current index of the
corresponding item.
Comparing Two Items by File Names
The procedure of comparing two items is described in the following paragraphs.
First we pass the parameters of the items to function CExplorerView::FindItem(…) to retrieve their
current indices. After the indices are obtained, we stuff a LV_ITEM type object, set LVIF_IMAGE bit of
member mask to “1” and call function CListCtrl::GetItem(…). Since in the sample, a directory item is
always associated with the default image (In the image list, the image index is 0), we can use an item’s
image index to tell if it represents a directory or a file. For different situations, the comparing function will
return different values (In the sample, a directory always preceeds a file item):
……
……
int CExplorerView::CompareByName(LPARAM lParam1, LPARAM lParam2, CListCtrl &lc)
{
nItem1=FindItem(lParam1, lc);
nItem2=FindItem(lParam2, lc);
memset(&lvi1, 0, sizeof(LV_ITEM));
memset(&lvi2, 0, sizeof(LV_ITEM));
lvi1.mask|=LVIF_IMAGE;
lvi1.iItem=nItem1;
lvi2.mask|=LVIF_IMAGE;
lvi2.iItem=nItem2;
lc.GetItem(&lvi1);
lc.GetItem(&lvi2);
szName1=lc.GetItemText(nItem1, 0);
szName2=lc.GetItemText(nItem2, 0);
if(lvi1.iImage == 0 && lvi2.iImage != 0)return -1;
if(lvi1.iImage != 0 && lvi2.iImage == 0)return 1;
In case both items are directories or files, we need to further compare their names. Since file names
under Windows are case insensitive, we neglect character case when performing the comparison. The
comparison is done within a for loop, which starts from the first characters and ends under one of the
following situations: 1) The two compared characters are different, in which case the character that has the
greater value belongs to the item that should follow the other. 2) One of the strings reaches its end. In this
case the item with longer file name should follow the other. If two strings are exactly the same, the function
returns 0:
……
nSize=min(szName1.GetLength(), szName2.GetLength());
szName1.MakeLower();
szName2.MakeLower();
for(i=0; i szName2[i])return 1;
}
if(i == nSize)
{
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