问题
INTRODUCTION AND RELEVANT INFORMATION:
I am trying to implement listview control with editable items and subitems. Instead of regular listview look, items and subitems should have edit control, checkbox or combo box.
I am using raw WinAPI and C++. I am targeting Windows XP onwards.
MY EFFORTS TO SOLVE THE PROBLEM:
After researching here and on the Internet, I was able to only find examples in MFC. They all use LVN_BEGINLABELEDIT technique to implement this behavior.
Unfortunately I do not understand entirely this concept so I have decided to start from scratch ( I consider this also to be the best approach for improving ones programming skills ).
MY CONCEPT:
I have decided to catch NM_DBLCLK for listview and to get coordinates from there using ListView_GetItemRect or ListView_GetSubItemRect macro.
Then I would simply move the combobox/checkbox/edit control over corresponding item/subitem ( combobox/edit control/checkbox would be created as separate, hidden windows ).
After user finishes with input ( by pressing enter or changing focus ) I would simply hide the combobox/checkbox/edit control.
MY CURRENT RESULTS:
At the moment, I am stuck with the dimensions of combobox/edit control/checkbox not being the same as item/subitem dimensions, when moved above the item/subitem.
QUESTION:
Can my code example submitted below be improved to properly adjust combobox/edit control/checkbox window size to the size of the item/subitem? For now, I will only focus on this part of the problem, to keep this question as short as possible.
Here is the instruction for creating small application that illustrates the problem. Notice that I have tried to keep things as minimal as I could:
1.) Create default Win32 project in Visual Studio ( I use VS 2008 ).
2.) Add the following WM_CREATE handler to main window's procedure:
case WM_CREATE:
{
HWND hEdit = CreateWindowEx( 0,WC_EDIT, L"",
WS_CHILD | WS_VISIBLE | WS_BORDER | ES_CENTER | ES_AUTOHSCROLL,
250, 10, 100, 20, hWnd, (HMENU)1500, hInst, 0 );
HWND hComboBox = CreateWindowEx( 0,WC_COMBOBOX, L"",
WS_CHILD | WS_VISIBLE | WS_BORDER | CBS_DROPDOWNLIST,
100, 10, 100, 20, hWnd, (HMENU)1600, hInst, 0 );
HWND hwndLV = CreateWindowEx( 0, WC_LISTVIEW,
L"Editable Subitems",
WS_CHILD | WS_VISIBLE | WS_BORDER |
LVS_REPORT | LVS_SINGLESEL,
150, 100, 250, 150, hWnd, (HMENU)2000, hInst, 0 );
// set extended listview styles
ListView_SetExtendedListViewStyle( GetDlgItem( hWnd, 2000 ),
LVS_EX_FULLROWSELECT | LVS_EX_GRIDLINES | LVS_EX_DOUBLEBUFFER );
// add some columns
LVCOLUMN lvc = {0};
lvc.iSubItem = 0;
lvc.mask = LVCF_FMT | LVCF_WIDTH | LVCF_TEXT | LVCF_SUBITEM;
lvc.fmt = LVCFMT_LEFT;
for (long nIndex = 0; nIndex < 5; nIndex++ )
{
wchar_t txt[50];
swprintf_s( txt, 50, L"Column %d", nIndex + 1 );
lvc.iSubItem = nIndex;
lvc.cx = 60;
lvc.pszText = txt;
ListView_InsertColumn( GetDlgItem( hWnd,2000 ), nIndex, &lvc );
}
// add some items
LVITEM lvi;
lvi.mask = LVIF_TEXT;
lvi.iItem = 0;
for( lvi.iItem = 0; lvi.iItem < 10; lvi.iItem++ )
for (long nIndex = 0; nIndex < 5; nIndex++ )
{
wchar_t txt[50];
swprintf_s( txt, 50, L"Item %d%d", lvi.iItem + 1, nIndex + 1 );
lvi.iSubItem = nIndex;
lvi.pszText = txt;
if( ! nIndex ) // item
SendDlgItemMessage( hWnd, 2000,
LVM_INSERTITEM, 0,
reinterpret_cast<LPARAM>(&lvi) );
else // sub-item
SendDlgItemMessage( hWnd, 2000,
LVM_SETITEM, 0,
reinterpret_cast<LPARAM>(&lvi) );
}
}
return 0L;
3.) Add the following handler for WM_NOTIFY in main window's procedure:
case WM_NOTIFY:
{
if( ((LPNMHDR)lParam)->code == NM_DBLCLK )
{
switch( ((LPNMHDR)lParam)->idFrom )
{
case 2000: // remember, this was our listview's ID
{
LPNMITEMACTIVATE lpnmia = (LPNMITEMACTIVATE)lParam;
// SHIFT/ALT/CTRL/their combination, must not be pressed
if( ( lpnmia->uKeyFlags || 0 ) == 0 )
{
// this is where we store item/subitem rectangle
RECT rc = { 0, 0, 0, 0 };
if( (lpnmia->iSubItem) <= 0 ) // this is item so we must call ListView_GetItemRect
{
// this rectangle holds proper left coordinate
// since ListView_GetItemRect with LVIR_LABEL flag
// messes up rectangle's left cordinate
RECT rcHelp = { 0, 0, 0, 0 };
// this call gets the length of entire row
// but holds proper left coordinate
ListView_GetItemRect( lpnmia->hdr.hwndFrom,
lpnmia->iItem, &rcHelp, LVIR_BOUNDS );
// this call gets proper rectangle except for the left side
ListView_GetItemRect( lpnmia->hdr.hwndFrom,
lpnmia->iItem, &rc, LVIR_LABEL );
// now we can correct the left coordinate
rc.left = rcHelp.left;
}
else // it is subitem, so we must call ListView_GetSubItemRect
{
ListView_GetSubItemRect( lpnmia->hdr.hwndFrom,
lpnmia->iItem, lpnmia->iSubItem,
LVIR_BOUNDS, &rc );
}
// convert listview client coordinates to parent coordinates
// so edit control can be properly moved
POINT p;
p.x = rc.left;
p.y = rc.top;
ClientToScreen( lpnmia->hdr.hwndFrom, &p );
ScreenToClient( hWnd, &p );
MoveWindow( GetDlgItem( hWnd, 1500 ),
p.x, p.y,
rc.right - rc.left,
rc.bottom - rc.top, TRUE );
// set focus to our edit control
HWND previousWnd = SetFocus( GetDlgItem( hWnd, 1500 ) );
}
}
break;
default:
break;
}
}
}
break;
And this is the result I get:
You can clearly see that top and bottom border of the edit control are not drawn properly. As for combobox, the width is properly adjusted, but height remains the same.
I have tried substituting MoveWindow call with SetWindowPos but the result was the same.
After further tampering, I have found out that NMITEMACTIVATE bugs when returning the rectangle of a subitem, if listview doesn't have LVS_EX_FULLROWSELECT style set. You can see this by simply commenting out the part in my WM_CREATE handler where I set this style. Maybe I am doing something wrong and this "bug" may be caused by my code, but I don't see the problem.
EDITED on September, 17th 2014:
After testing the values for iItem and iSubItem members of NMITEMACTIVATE structure when listview doesn't have LVS_EX_FULLROWSELECT I can verify that the bug is not in my code. It always returns iItem to be 0, no matter which subitem I click. This explains the faulty behavior I got when removing this style.
If any further info is required please leave a comment and I will act as soon as possible.
Thank you for your time and efforts to help.
回答1:
The issue you're facing is multi-faceted.
Firstly, the default font of the edit control is larger (higher) than that of the list-view. You can fix this one quite trivially, by first getting the font from the list-view and then setting it to the edit control. Doing this will then make the bottom border of the control visible.
The next issue is that the caret of the edit control needs a pixel above and below it, to ensure that the control doesn't have its borders interfered with. In addition to this 1 pixel of 'space' you then need another pixel for the border.
Added to this second point, the dimensions calculated by rc.right - rc.left and rc.bottom - rc.top are 1 pixel too small. Think of a rect that starts at 1,1 and extends to 2,2 - this is a rect of 4 pixels - 2 wide and 2 high. Simply subtracting the top/left from the bottom/right would give you a width/height of only 1 pixel each. To fix this, you need to add 1 to each of these subtractions.
Finally, since the caret is exactly the height of the 'client-area' of each item/sub-item, you need to make the edit control 2 pixels taller than the item/sub-item, and start 1 2 pixels higher than it does currently.
Here's the output I get when making the suggested changes:
And here's the changes/additions I made.
1. Get/Set the font. (inserted after creating the list-view and before setting its extended style)
HFONT lvFont = (HFONT)SendDlgItemMessage(hWnd, 2000, WM_GETFONT, 0, 0);
SendDlgItemMessage(hWnd, 1500, WM_SETFONT, (WPARAM)lvFont, TRUE);
2. Set the window position/size
MoveWindow( GetDlgItem( hWnd, 1500 ),
p.x, p.y-2,
1+ rc.right - rc.left,
1+ 2 + rc.bottom - rc.top, TRUE );
Finally, contrast this against the original output from your code:
UPDATE: Here's a snapshot of the appearance when the built-in label editing functionality is used (LVS_EDITLABELS style)
来源：https://stackoverflow.com/questions/25895351/window-size-of-edit-control-combobox-is-not-properly-adjusted-when-using-movewin