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自绘LISTVIEW的滚动条(Delphi实现)
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因项目需要准备对LISTVIEW的滚动条进行自绘。于是在网上搜了一下，问题没解决，却搜出一篇令人不愉快的帖子 。确实，那时候实力是不够的，但现在应该是没问题了，为这个目的才不断磨练自己的。
LISTVIEW控件的滚动条是系统自带的，它不创建窗口。对LISTVIEW窗口本身进行子类化后，要处理一些跟滚动条有关的消息。
首先是要骗过WM_NCPAINT消息。这个十分容易。WM_NCPAINT消息的wParam是一个区域的句柄。当它不为1时，从它里面CLIP 掉滚动条的区域，再传给原窗口过程即可。当它为1时，创建一个包含控件全客户区域的Region，再从中CLIP掉滚动条的区域，传给原窗口过程。
然后是WM_HSCROLL和WM_VSCROLL消息。在调用原窗口过程之前需要去掉窗口的WS_HSCROLL和WS_VSCROLL样式，否 则窗口过程就会在消息中绘制滚动条。调用后需要恢复。同时为避免窗口在WM_STYLECHANGING和WM_STYLECHANGED消息中重绘，也 需要截获这两个消息。
WM_NCCALCSIZE消息也是必须截获的。如果是在处理WM_HSCROLL和WM_VSCROLL消息的过程中响应WM_NCCALCSIZE，则必须去掉WS_HSCROLL和WS_VSCROLL样式。
然后是WM_ERASEBACKGROUND,WM_MOUSEWHELL消息。在这消息后需要重绘滚动条。
最重要的莫过于WM_NCHITTEST消息了。因为是自绘，所以滚动条的按下和拖动都必须在这里处理。
在自己写的滚动条Track函数中，最头疼的莫过于ThumbTrack了。当你计算好滚动到的绝对位置后，用SendMessage(hWnd, WM_XSCROLL, MAKEWPARAM(SB_THUMBTRACK, Pos), 0)发给窗口时，它居然没有反应。这是因为窗口过程不会从消息中取得TrackPos，而是会调用GetScrollInfo的API取得 TrackPos（因为前者只有16位）。但是使用SetScrollInfo是没办法设置TrackPos的。虽然你可以用SIF_POS标志让它同时 设置Pos和TrackPos，但当Pos等于TrackPos时，窗口过程不会做任何响应。从windows源代码中我们可以了解到，TrackPos 并不会为每个窗口保存一份，实际上，在任一时刻最多只有一个滚动条在做ThumbTrack的操作，因此系统只需要用一个全局变量来保存就可以了。
解决这个问题的办法是HookAPI。在GetScrollInfo中返回我们自己的TrackPos。要注意的是要Hook的不是本模块的 API，而是ComCtl32.dll中的GetScrollInfo。因此简单的如往@GetScrollInfo地址写几句跳转的方法是行不通的。必 须遍历ComCtl32.dll的pe头。这种技术在很多文章中都有描述。
不多说了，以下是Delphi代码，要点在前面已有描述，源码中没有做特殊说明。
使用说明：
资源中是一张横条的192*16的位图，从左到右依次是：左箭头、右箭头、上箭头、下箭头、左箭头按下、右箭头按下、上箭头按下、下箭头按下、横Thumb条、纵Thumb条、横背景条、纵背景条。
初始化时，调用GetSkinSB.InitSkinSB(ListView1.Handle);即可。窗口销毁前调用GetSkinSB.UninitSkinSB(ListView1.Handle)。
虽然也可针对EDIT(TMemo)和其它使用系统滚动条的控件使用此模块，但效果各有差异，需要分别做特殊处理。
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unit
SkinSB;
interface
uses
SysUtils, Classes, Windows, Messages, Graphics;
const
SKINSB_PROP =
'{8BC6661E-5880-4353-878D-C3B3784CFC5F}'
;
type
TBarPosCode = ( bpcNone,
bpcHArrowL, bpcHArrowR, bpcHPageL, bpcHPageR, bpcHThumb,
bpcVArrowU, bpcVArrowD, bpcVPageU, bpcVPageD, bpcVThumb,
bpcCross );
TWindowProc =
function
(hWnd: HWND; uMsg: UINT; wParam: WPARAM; lParam: LPARAM): LRESULT; stdcall;
PSkinSBInfo = ^TSkinSBInfo;
TSkinSBInfo =
packed
record
OldWndProc: TWindowProc;
Prevent:
Boolean
;
// prevent style change message
Scrolling:
Boolean
;
Style:
Cardinal
;
// real style
ThumbTrack:
Boolean
;
ThumbPos:
Integer
;
Tracking:
Boolean
;
// tracking: click arrow or track thumb
end
;
TSkinSB =
class
protected
FBitmap: TBitmap;
constructor
CreateInstance;
public
constructor
Create;
destructor
Destroy; override;
procedure
InitSkinSB(H: HWND);
procedure
UnInitSkinSB(H: HWND);
procedure
DrawElem(H: HWND; Code: TBarPosCode; R: TRect; Down:
Boolean
);
end
;
function
GetSkinSB: TSkinSB;
function
SkinSBWndProc(hWnd: HWND; uMsg: UINT; wParam: WPARAM; lParam: LPARAM): LRESULT; stdcall;
function
GetSkinSBInfo(hWnd: HWND): PSkinSBInfo;
implementation
uses
CommCtrl;
{$R *.res}
var
l_SkinSB: TSkinSB;
l_SkinSB_Prop: TATOM;
type
PImageImportDescriptor = ^TImageImportDescriptor;
TImageImportDescriptor =
packed
record
OriginalFirstThunk: DWORD;
// or Characteristics: DWORD
TimeDateStamp: DWORD;
ForwarderChain: DWORD;
Name: DWORD;
FirstThunk: DWORD;
end
;
PImageChunkData = ^TImageChunkData;
TImageChunkData =
packed
record
case
Integer
of
0
: ( ForwarderString: DWORD );
1
: ( Func: DWORD );
2
: ( Ordinal: DWORD );
3
: ( AddressOfData: DWORD );
end
;
PImageImportByName = ^TImageImportByName;
TImageImportByName =
packed
record
Hint:
Word
;
Name:
array
[
0..0
]
of
Byte
;
end
;
type
PHookRec = ^THookRec;
THookRec =
packed
record
OldFunc:
Pointer
;
NewFunc:
Pointer
;
end
;
var
_HookGetScrollInfo: THookRec;
procedure
HookApiInMod(ImageBase:
Cardinal
; ApiName:
PChar
; PHook: PHookRec);
var
pidh: PImageDosHeader;
pinh: PImageNtHeaders;
pSymbolTable: PIMAGEDATADIRECTORY;
piid: PIMAGEIMPORTDESCRIPTOR;
pitd_org, pitd_1st: PImageChunkData;
piibn: PImageImportByName;
pAPIFunction:
Pointer
;
written, oldAccess: DWORD;
begin
if
ImageBase =
0
then
Exit;
pidh := PImageDosHeader(ImageBase);
pinh := PImageNtHeaders(DWORD(ImageBase) +
Cardinal
(pidh^._lfanew));
pSymbolTable := @pinh^.OptionalHeader
.
DataDirectory[
1
];
piid := PImageImportDescriptor(DWORD(ImageBase) + pSymbolTable^.VirtualAddress);
repeat
pitd_org := PImageChunkData(DWORD(ImageBase) + piid^.OriginalFirstThunk);
pitd_1st := PImageChunkData(DWORD(ImageBase) + piid^.FirstThunk);
repeat
piibn := PImageImportByName(DWORD(ImageBase) + LPDWORD(pitd_org)^);
pAPIFunction :=
Pointer
(pitd_1st^.Func);
if
StrComp(ApiName, @piibn^.Name) =
0
then
begin
PHook^.OldFunc := pAPIFunction;
VirtualProtect(@(pitd_1st^.Func), SizeOf(DWORD), PAGE_WRITECOPY, oldAccess);
WriteProcessMemory(GetCurrentProcess(), @(pitd_1st^.Func), @PHook^.NewFunc, SizeOf(DWORD), written);
VirtualProtect(@(pitd_1st^.Func), SizeOf(DWORD), oldAccess, oldAccess);
end
;
Inc(pitd_org);
Inc(pitd_1st);
until
pitd_1st^.Func =
0
;
Inc(piid);
until
piid^.FirstThunk + piid^.OriginalFirstThunk + piid^.ForwarderChain + piid^.Name =
0
;
end
;
function
GetSkinSBInfo(hWnd: HWND): PSkinSBInfo;
begin
Result := PSkinSBInfo( GetProp(hWnd, MAKEINTATOM(l_SkinSB_Prop)) );
end
;
function
GetSkinSB: TSkinSB;
begin
if
l_SkinSB =
nil
then
l_SkinSB := TSkinSB
.
CreateInstance;
Result := l_SkinSB;
end
;
function
CalcScrollBarRect(H: HWND; nBarCode:
Cardinal
): TRect;
var
Style, ExStyle:
Cardinal
;
begin
SetRect(Result,
0
,
0
,
0
,
0
);
Style := GetWindowLong(H, GWL_STYLE);
ExStyle := GetWindowLong(H, GWL_EXSTYLE);
if
(nBarCode = SB_HORZ)
and
((Style
and
WS_HSCROLL) =
0
)
then
Exit;
if
(nBarCode = SB_VERT)
and
((Style
and
WS_VSCROLL) =
0
)
then
Exit;
GetWindowRect(H, Result);
OffsetRect(Result, -Result
.
Left, -Result
.
Top);
if
((ExStyle
and
WS_EX_DLGMODALFRAME) <>
0
)
or
((ExStyle
and
WS_EX_CLIENTEDGE) <>
0
)
then
begin
InflateRect(Result, -GetSystemMetrics(SM_CXEDGE), -GetSystemMetrics(SM_CYEDGE));
end
;
// special: returns the cross
if
nBarCode = SB_BOTH
then
begin
if
((Style
and
WS_HSCROLL) =
0
)
or
((Style
and
WS_VSCROLL) =
0
)
then
begin
SetRect(Result,
0
,
0
,
0
,
0
);
Exit;
end
;
Result
.
Top := Result
.
Bottom - GetSystemMetrics(SM_CYVSCROLL);
if
(ExStyle
and
WS_EX_LEFTSCROLLBAR) <>
0
then
Result
.
Right := Result
.
Left + GetSystemMetrics(SM_CXHSCROLL)
else
Result
.
Left := Result
.
Right - GetSystemMetrics(SM_CXHSCROLL);
Exit;
end
;
if
nBarCode = SB_HORZ
then
begin
// if (ExStyle and WS_EX_TOPSCROLLBAR) <> 0 then Result.Bottom := Result.Top + GetSystemMetrics(SM_CYVSCROLL)
Result
.
Top := Result
.
Bottom - GetSystemMetrics(SM_CYVSCROLL);
if
((Style
and
WS_VSCROLL) <>
0
)
then
Dec(Result
.
Right, GetSystemMetrics(SM_CYVSCROLL));
end
;
if
nBarCode = SB_VERT
then
begin
if
(ExStyle
and
WS_EX_LEFTSCROLLBAR) <>
0
then
Result
.
Right := Result
.
Left + GetSystemMetrics(SM_CXHSCROLL)
else
Result
.
Left := Result
.
Right - GetSystemMetrics(SM_CXHSCROLL);
if
((Style
and
WS_HSCROLL) <>
0
)
then
Dec(Result
.
Bottom, GetSystemMetrics(SM_CXHSCROLL));
end
;
end
;
type
TBarElem = (beArrow1, beBG, beThumb, beArrow2);
TBarElemRects =
array
[TBarElem]
of
TRect;
function
CalcBarElemRects(hWnd: HWND; nBarCode:
Integer
): TBarElemRects;
var
R: TRect;
SI: TScrollInfo;
ThumbSize:
Integer
;
X, L, H, BlockH, BlockV:
Integer
;
begin
R := CalcScrollBarRect(hWnd, nBarCode);
SI
.
cbSize := SizeOf(SI);
SI
.
fMask := SIF_ALL;
GetScrollInfo(hWnd, nBarCode, SI);
Result[beArrow1] := R;
Result[beArrow2] := R;
Result[beBG] := R;
Result[beThumb] := R;
if
nBarCode = SB_VERT
then
begin
BlockV := GetSystemMetrics(SM_CYVSCROLL);
L := Result[beArrow1].Top + BlockV;
H := Result[beArrow2].Bottom - BlockV;
Result[beArrow1].Bottom := L;
Result[beArrow2].Top := H;
// Inc(L);
// Dec(H);
Result[beBG].Top := L;
Result[beBG].Bottom := H;
end
else
begin
BlockH := GetSystemMetrics(SM_CXHSCROLL);
L := Result[beArrow1].Left + BlockH;
H := Result[beArrow2].Right - BlockH;
Result[beArrow1].Right := L;
Result[beArrow2].Left := H;
// Inc(L);
// Dec(H);
Result[beBG].Left := L;
Result[beBG].Right := H;
end
;
if
SI
.
nMax - SI
.
nMin -
Integer
(SI
.
nPage) +
1
<=
0
then
begin
// max thumb, no thumb
if
nBarCode = SB_VERT
then
begin
Result[beThumb].Top := L;
Result[beThumb].Bottom := H;
end
else
begin
Result[beThumb].Left := L;
Result[beThumb].Right := H;
end
;
Exit;
end
;
ThumbSize := MulDiv(H - L, SI
.
nPage, SI
.
nMax - SI
.
nMin +
1
);
X := L + MulDiv(SI
.
nTrackPos, H - ThumbSize - L, SI
.
nMax -
Integer
(SI
.
nPage) - SI
.
nMin +
1
);
if
nBarCode = SB_VERT
then
begin
Result[beThumb].Top := X;
Result[beThumb].Bottom := X + ThumbSize;
end
else
begin
Result[beThumb].Left := X;
Result[beThumb].Right := X + ThumbSize;
end
;
end
;
function
GetPtBarPos(H: HWND; Pt: TPoint): TBarPosCode;
var
R: TRect;
BR: TBarElemRects;
begin
Result := bpcNone;
R := CalcScrollBarRect(H, SB_HORZ);
InflateRect(R, GetSystemMetrics(SM_CXEDGE), GetSystemMetrics(SM_CYEDGE));
if
PtInRect(R, Pt)
then
begin
BR := CalcBarElemRects(H, SB_HORZ);
if
PtInRect(BR[beArrow1], Pt)
then
Result := bpcHArrowL
else
if
PtInRect(BR[beThumb], Pt)
then
Result := bpcHThumb
else
if
PtInRect(BR[beArrow2], Pt)
then
Result := bpcHArrowR
else
if
Pt
.
X < BR[beThumb].Left
then
Result := bpcHPageL
else
Result := bpcHPageR;
Exit;
end
;
R := CalcScrollBarRect(H, SB_VERT);
InflateRect(R, GetSystemMetrics(SM_CXEDGE), GetSystemMetrics(SM_CYEDGE));
if
PtInRect(R, Pt)
then
begin
BR := CalcBarElemRects(H, SB_VERT);
if
PtInRect(BR[beArrow1], Pt)
then
Result := bpcVArrowU
else
if
PtInRect(BR[beThumb], Pt)
then
Result := bpcVThumb
else
if
PtInRect(BR[beArrow2], Pt)
then
Result := bpcVArrowD
else
if
Pt
.
Y < BR[beThumb].Top
then
Result := bpcVPageU
else
Result := bpcVPageD;
Exit;
end
;
end
;
type
TGetScrollInfoFunc =
function
(H: HWND; Code:
Integer
;
var
SI: TScrollInfo):
Boolean
; stdcall;
function
_SkinSB_GetScrollInfo(H: HWND; Code:
Integer
;
var
SI: TScrollInfo):
Boolean
; stdcall;
var
P: PSkinSBInfo;
begin
Result := TGetScrollInfoFunc(_HookGetScrollInfo
.
OldFunc)(H, Code, SI);
P := GetSkinSBInfo(H);
if
(P <>
nil
)
and
P^.ThumbTrack
and
((SI
.
fMask
and
SIF_TRACKPOS) <>
0
)
then
begin
SI
.
nTrackPos := P^.ThumbPos;
end
;
end
;
{ TSkinSB }
constructor
TSkinSB
.
Create;
begin
raise
Exception
.
Create(
'use GetSkinSB.'
);
end
;
constructor
TSkinSB
.
CreateInstance;
begin
inherited
;
_HookGetScrollInfo
.
OldFunc :=
nil
;
_HookGetScrollInfo
.
NewFunc := @_SkinSB_GetScrollInfo;
HookApiInMod( GetModuleHandle(
'comctl32.dll'
),
'GetScrollInfo'
, @_HookGetScrollInfo );
FBitmap := TBitmap
.
Create;
FBitmap
.
LoadFromResourceName(hInstance,
'scrollbar'
);
end
;
destructor
TSkinSB
.
Destroy;
begin
FreeAndNil(FBitmap);
inherited
;
end
;
procedure
TSkinSB
.
DrawElem(H: HWND; Code: TBarPosCode; R: TRect;
Down:
Boolean
);
var
Canvas: TCanvas;
begin
Canvas := TCanvas
.
Create;
try
Canvas
.
Handle := GetWindowDC(H);
try
case
Code
of
bpcHArrowL:
begin
if
Down
then
BitBlt(Canvas
.
Handle, R
.
Left, R
.
Top,
16
,
16
, FBitmap
.
Canvas
.
Handle,
64
,
0
, SRCCOPY)
else
BitBlt(Canvas
.
Handle, R
.
Left, R
.
Top,
16
,
16
, FBitmap
.
Canvas
.
Handle,
0
,
0
, SRCCOPY);
Exit;
end
;
bpcHArrowR:
begin
if
Down
then
BitBlt(Canvas
.
Handle, R
.
Left, R
.
Top,
16
,
16
, FBitmap
.
Canvas
.
Handle,
80
,
0
, SRCCOPY)
else
BitBlt(Canvas
.
Handle, R
.
Left, R
.
Top,
16
,
16
, FBitmap
.
Canvas
.
Handle,
16
,
0
, SRCCOPY);
Exit;
end
;
bpcHThumb:
begin
BitBlt(Canvas
.
Handle, R
.
Left, R
.
Top,
2
,
16
, FBitmap
.
Canvas
.
Handle,
128
,
0
, SRCCOPY);
BitBlt(Canvas
.
Handle, R
.
Right -
2
, R
.
Top,
2
,
16
, FBitmap
.
Canvas
.
Handle,
142
,
0
, SRCCOPY);
StretchBlt(Canvas
.
Handle, R
.
Left +
2
, R
.
Top, R
.
Right - R
.
Left -
4
,
16
, FBitmap
.
Canvas
.
Handle,
130
,
0
,
12
,
16
, SRCCOPY);
Exit;
end
;
bpcHPageL, bpcHPageR:
begin
if
R
.
Right - R
.
Left <
4
then
begin
StretchBlt(Canvas
.
Handle, R
.
Left, R
.
Top, R
.
Right - R
.
Left,
16
, FBitmap
.
Canvas
.
Handle,
160
,
0
,
16
,
16
, SRCCOPY);
end
else
begin
BitBlt(Canvas
.
Handle, R
.
Left, R
.
Top,
2
,
16
, FBitmap
.
Canvas
.
Handle,
160
,
0
, SRCCOPY);
BitBlt(Canvas
.
Handle, R
.
Right -
2
, R
.
Top,
2
,
16
, FBitmap
.
Canvas
.
Handle,
174
,
0
, SRCCOPY);
StretchBlt(Canvas
.
Handle, R
.
Left +
2
, R
.
Top, R
.
Right - R
.
Left -
4
,
16
, FBitmap
.
Canvas
.
Handle,
162
,
0
,
12
,
16
, SRCCOPY);
end
;
Exit;
end
;
bpcVArrowU:
begin
if
Down
then
BitBlt(Canvas
.
Handle, R
.
Left, R
.
Top,
16
,
16
, FBitmap
.
Canvas
.
Handle,
96
,
0
, SRCCOPY)
else
BitBlt(Canvas
.
Handle, R
.
Left, R
.
Top,
16
,
16
, FBitmap
.
Canvas
.
Handle,
32
,
0
, SRCCOPY);
Exit;
end
;
bpcVArrowD:
begin
if
Down
then
BitBlt(Canvas
.
Handle, R
.
Left, R
.
Top,
16
,
16
, FBitmap
.
Canvas
.
Handle,
112
,
0
, SRCCOPY)
else
BitBlt(Canvas
.
Handle, R
.
Left, R
.
Top,
16
,
16
, FBitmap
.
Canvas
.
Handle,
48
,
0
, SRCCOPY);
Exit;
end
;
bpcVThumb:
begin
BitBlt(Canvas
.
Handle, R
.
Left, R
.
Top,
16
,
2
, FBitmap
.
Canvas
.
Handle,
144
,
0
, SRCCOPY);
BitBlt(Canvas
.
Handle, R
.
Left, R
.
Bottom -
2
,
16
,
2
, FBitmap
.
Canvas
.
Handle,
144
,
14
, SRCCOPY);
StretchBlt(Canvas
.
Handle, R
.
Left, R
.
Top +
2
,
16
, R
.
Bottom - R
.
Top -
4
, FBitmap
.
Canvas
.
Handle,
144
,
2
,
16
,
12
, SRCCOPY);
Exit;
end
;
bpcVPageU, bpcVPageD:
begin
if
R
.
Bottom - R
.
Top <
4
then
begin
StretchBlt(Canvas
.
Handle, R
.
Left, R
.
Top,
16
, R
.
Bottom - R
.
Top, FBitmap
.
Canvas
.
Handle,
176
,
0
,
16
,
16
, SRCCOPY);
end
else
begin
BitBlt(Canvas
.
Handle, R
.
Left, R
.
Top,
16
,
2
, FBitmap
.
Canvas
.
Handle,
176
,
0
, SRCCOPY);
BitBlt(Canvas
.
Handle, R
.
Left, R
.
Bottom -
2
,
16
,
2
, FBitmap
.
Canvas
.
Handle,
176
,
14
, SRCCOPY);
StretchBlt(Canvas
.
Handle, R
.
Left, R
.
Top +
2
,
16
, R
.
Bottom - R
.
Top -
4
, FBitmap
.
Canvas
.
Handle,
176
,
2
,
16
,
12
, SRCCOPY);
end
;
Exit;
end
;
end
;
Canvas
.
Pen
.
Color := clBlack;
Canvas
.
Brush
.
Color := clWhite;
Canvas
.
Rectangle(R);
finally
ReleaseDC(H, Canvas
.
Handle);
end
;
finally
Canvas
.
Handle :=
0
;
FreeAndNil(Canvas);
end
;
end
;
procedure
TSkinSB
.
InitSkinSB(H: HWND);
var
PInfo: PSkinSBInfo;
begin
PInfo := GetSkinSBInfo(H);
if
PInfo <>
nil
then
Exit;
// already inited
New(PInfo);
PInfo^.OldWndProc := TWindowProc(GetWindowLong(H, GWL_WNDPROC));
PInfo^.Style := GetWindowLong(H, GWL_STYLE);
PInfo^.Prevent :=
False
;
PInfo^.Scrolling :=
False
;
PInfo^.ThumbTrack :=
False
;
SetWindowLong(H, GWL_WNDPROC,
Cardinal
(@SkinSBWndProc));
SetProp(H, MAKEINTATOM(l_SkinSB_Prop),
Cardinal
(PInfo));
end
;
procedure
TSkinSB
.
UnInitSkinSB(H: HWND);
var
PInfo: PSkinSBInfo;
begin
PInfo := GetSkinSBInfo(H);
if
PInfo =
nil
then
Exit;
// not inited
RemoveProp(H, MAKEINTATOM(l_SkinSB_Prop));
SetWindowLong(H, GWL_WNDPROC,
Cardinal
(@PInfo^.OldWndProc));
Dispose(PInfo);
end
;
const
WM_REPEAT_CLICK = WM_USER +
$6478
;
procedure
OnRepeatClickTimer(hWnd: HWND; uMsg: UINT; idEvent: UINT; dwTime: DWORD); stdcall;
begin
KillTimer(
0
, idEvent);
PostThreadMessage(MainThreadID, WM_REPEAT_CLICK,
0
,
0
);
end
;
procedure
RedrawScrollBars(hWnd: HWND);
var
RHBar, RVBar, RCross: TRect;
BR: TBarElemRects;
begin
RHBar := CalcScrollBarRect(hWnd, SB_HORZ);
if
not
IsRectEmpty(RHBar)
then
begin
BR := CalcBarElemRects(hWnd, SB_HORZ);
GetSkinSB
.
DrawElem(hWnd, bpcHPageL, Rect(BR[beBG].Left, BR[beBG].Top, BR[beThumb].Left, BR[beBG].Bottom),
False
);
GetSkinSB
.
DrawElem(hWnd, bpcHPageR, Rect(BR[beThumb].Right, BR[beBG].Top, BR[beBG].Right, BR[beBG].Bottom),
False
);
GetSkinSB
.
DrawElem(hWnd, bpcHThumb, BR[beThumb],
False
);
GetSkinSB
.
DrawElem(hWnd, bpcHArrowL, BR[beArrow1],
False
);
GetSkinSB
.
DrawElem(hWnd, bpcHArrowR, BR[beArrow2],
False
);
end
;
RVBar := CalcScrollBarRect(hWnd, SB_VERT);
if
not
IsRectEmpty(RVBar)
then
begin
BR := CalcBarElemRects(hWnd, SB_VERT);
GetSkinSB
.
DrawElem(hWnd, bpcVPageU, Rect(BR[beBG].Left, BR[beBG].Top, BR[beBG].Right, BR[beThumb].Top),
False
);
GetSkinSB
.
DrawElem(hWnd, bpcVPageD, Rect(BR[beBG].Left, BR[beThumb].Bottom, BR[beBG].Right, BR[beBG].Bottom),
False
);
GetSkinSB
.
DrawElem(hWnd, bpcVThumb, BR[beThumb],
False
);
GetSkinSB
.
DrawElem(hWnd, bpcVArrowU, BR[beArrow1],
False
);
GetSkinSB
.
DrawElem(hWnd, bpcVArrowD, BR[beArrow2],
False
);
end
;
RCross := CalcScrollBarRect(hWnd, SB_BOTH);
if
not
IsRectEmpty(RCross)
then
begin
GetSkinSB
.
DrawElem(hWnd, bpcCross, RCross,
False
);
end
;
end
;
procedure
TrackBar(hWnd: HWND; nBarCode:
Integer
; PosCode: TBarPosCode; BarElem: TBarElem; MsgCode:
Integer
);
var
BR: TBarElemRects;
Msg: tagMSG;
Pt: TPoint;
R: TRect;
ScrollMsg:
Cardinal
;
RepeatClick:
Boolean
;
idEvent: UINT;
SI: TScrollInfo;
procedure
RefreshRect;
begin
BR := CalcBarElemRects(hWnd, nBarCode);
R := BR[BarElem];
end
;
begin
RepeatClick :=
False
;
BR := CalcBarElemRects(hWnd, nBarCode);
R := BR[BarElem];
GetScrollInfo(hWnd, nBarCode, SI);
if
nBarCode = SB_HORZ
then
ScrollMsg := WM_HSCROLL
else
ScrollMsg := WM_VSCROLL;
if
BarElem = beBG
then
begin
if
PosCode = bpcHPageL
then
R
.
Right := BR[beThumb].Left
else
if
PosCode = bpcHPageR
then
R
.
Left := BR[beThumb].Right
else
if
PosCode = bpcVPageU
then
R
.
Bottom := BR[beThumb].Top
else
if
PosCode = bpcVPageD
then
R
.
Top := BR[beThumb].Bottom;
end
;
GetSkinSB
.
DrawElem(hWnd, PosCode, R,
True
);
GetSkinSBInfo(hWnd)^.Tracking :=
True
;
idEvent :=
0
;
try
SetCapture(hWnd);
idEvent := SetTimer(
0
,
0
,
1000
, @OnRepeatClickTimer);
while
GetCapture = hWnd
do
begin
if
not
GetMessage(Msg,
0
,
0
,
0
)
then
Break;
if
(Msg
.
hwnd =
0
)
and
(Msg
.
message = WM_REPEAT_CLICK)
then
begin
GetCursorPos(Pt);
ScreenToClient(hWnd, Pt);
if
PtInRect(R, Pt)
then
begin
RepeatClick :=
True
;
SendMessage(hWnd, ScrollMsg, MsgCode,
0
);
SendMessage(hWnd, ScrollMsg, SB_ENDSCROLL,
0
);
RefreshRect;
GetSkinSB
.
DrawElem(hWnd, PosCode, R,
True
);
// if MsgCode = SB_LINEDOWN then SetScrollPos(hWnd, nBarCode, GetScrollPos(hWnd, nBarCode) + 1, False);
if
MsgCode = SB_PAGEDOWN
then
SetScrollPos(hWnd, nBarCode, GetScrollPos(hWnd, nBarCode) +
Integer
(SI
.
nPage),
False
);
// if MsgCode = SB_LINEUP then SetScrollPos(hWnd, nBarCode, GetScrollPos(hWnd, nBarCode) - 1, False);
if
MsgCode = SB_PAGEUP
then
SetScrollPos(hWnd, nBarCode, GetScrollPos(hWnd, nBarCode) -
Integer
(SI
.
nPage),
False
);
RedrawScrollBars(hWnd);
SetTimer(
0
,
0
,
80
, @OnRepeatClickTimer);
end
;
end
else
if
Msg
.
hwnd = hWnd
then
begin
case
Msg
.
message
of
WM_LBUTTONUP:
begin
if
RepeatClick
then
Break;
GetCursorPos(Pt);
ScreenToClient(hWnd, Pt);
if
PtInRect(R, Pt)
then
begin
SendMessage(hWnd, ScrollMsg, MsgCode,
0
);
SendMessage(hWnd, ScrollMsg, SB_ENDSCROLL,
0
);
RefreshRect;
// if MsgCode = SB_LINEDOWN then SetScrollPos(hWnd, nBarCode, GetScrollPos(hWnd, nBarCode) + 1, False);
if
MsgCode = SB_PAGEDOWN
then
SetScrollPos(hWnd, nBarCode, GetScrollPos(hWnd, nBarCode) +
Integer
(SI
.
nPage),
False
);
// if MsgCode = SB_LINEUP then SetScrollPos(hWnd, nBarCode, GetScrollPos(hWnd, nBarCode) - 1, False);
if
MsgCode = SB_PAGEUP
then
SetScrollPos(hWnd, nBarCode, GetScrollPos(hWnd, nBarCode) -
Integer
(SI
.
nPage),
False
);
end
;
Break;
end
;
end
;
end
;
DispatchMessage(Msg);
end
;
finally
if
idEvent <>
0
then
KillTimer(
0
, idEvent);
if
IsWindow(hWnd)
then
begin
if
GetCapture = hWnd
then
ReleaseCapture;
GetSkinSB
.
DrawElem(hWnd, PosCode, R,
False
);
GetSkinSBInfo(hWnd)^.Tracking :=
False
;
end
;
end
;
end
;
procedure
TrackThumb(hWnd: HWND; nBarCode:
Integer
; PosCode: TBarPosCode; BarElem: TBarElem);
var
BR: TBarElemRects;
Msg: tagMSG;
Pt: TPoint;
DragX:
Integer
;
R: TRect;
ScrollMsg:
Cardinal
;
SI, SI2: TScrollInfo;
Pos:
Integer
;
H, L, ThumbSize, X:
Integer
;
Pushed:
Boolean
;
function
ValidDragArea(ARect: TRect; APt: TPoint):
Boolean
;
begin
if
nBarCode = SB_HORZ
then
Result :=
Abs
((ARect
.
Bottom + ARect
.
Top)
div
2
- APt
.
Y) <
150
else
Result :=
Abs
((ARect
.
Left + ARect
.
Right)
div
2
- APt
.
X) <
150
;
end
;
function
CalcPos(ARect: TRect; APt: TPoint; ADragX:
Integer
):
Integer
;
var
NewX:
Integer
;
begin
if
nBarCode = SB_HORZ
then
NewX := APt
.
X - ADragX
else
NewX := APt
.
Y - ADragX;
Result := SI
.
nMin + MulDiv(NewX - L, SI
.
nMax -
Integer
(SI
.
nPage) - SI
.
nMin +
1
, H - L - ThumbSize);
if
Result < SI
.
nMin
then
Result := SI
.
nMin;
if
Result > SI
.
nMax -
Integer
(SI
.
nPage) +
1
then
Result := SI
.
nMax -
Integer
(SI
.
nPage) +
1
;
end
;
procedure
UpdateDragBar(ADown:
Boolean
; APos:
Integer
= -
10000
);
var
W:
Integer
;
begin
BR := CalcBarElemRects(hWnd, nBarCode);
R := BR[BarElem];
if
nBarCode = SB_HORZ
then
begin
if
APos <> -
10000
then
begin
W := R
.
Right - R
.
Left;
if
APos < BR[beArrow1].Right
then
APos := BR[beArrow1].Right;
if
APos + W > BR[beArrow2].Left
then
APos := BR[beArrow2].Left - W;
R
.
Left := APos;
R
.
Right := APos + W;
end
;
GetSkinSB
.
DrawElem(hWnd, bpcHPageL, Rect(BR[beBG].Left, BR[beBG].Top, R
.
Left, BR[beBG].Bottom),
False
);
GetSkinSB
.
DrawElem(hWnd, bpcHPageR, Rect(R
.
Right, BR[beBG].Top, BR[beBG].Right, BR[beBG].Bottom),
False
);
end
else
begin
if
APos <> -
10000
then
begin
W := R
.
Bottom - R
.
Top;
if
APos < BR[beArrow1].Bottom
then
APos := BR[beArrow1].Bottom;
if
APos + W >= BR[beArrow2].Top
then
APos := BR[beArrow2].Top - W -
1
;
R
.
Top := APos;
R
.
Bottom := APos + W;
end
;
GetSkinSB
.
DrawElem(hWnd, bpcVPageU, Rect(BR[beBG].Left, BR[beBG].Top, BR[beBG].Right, R
.
Top),
False
);
GetSkinSB
.
DrawElem(hWnd, bpcVPageD, Rect(BR[beBG].Left, R
.
Bottom, BR[beBG].Right, BR[beBG].Bottom),
False
);
end
;
GetSkinSB
.
DrawElem(hWnd, PosCode, R, ADown);
OutputDebugString(
PChar
(Format(
'R=(%d,%d,%d,%d)'
, [R
.
Left, R
.
Top, R
.
Right, R
.
Bottom])));
end
;
begin
BR := CalcBarElemRects(hWnd, nBarCode);
R := BR[BarElem];
if
nBarCode = SB_HORZ
then
ScrollMsg := WM_HSCROLL
else
ScrollMsg := WM_VSCROLL;
SI
.
cbSize := SizeOf(SI);
SI
.
fMask := SIF_ALL;
GetScrollInfo(hWnd, nBarCode, SI);
GetCursorPos(Pt);
ScreenToClient(hWnd, Pt);
if
nBarCode = SB_HORZ
then
begin
DragX := Pt
.
X - BR[beThumb].Left;
ThumbSize := BR[beThumb].Right - BR[beThumb].Left;
L := BR[beArrow1].Right;
H := BR[beArrow2].Left;
end
else
begin
DragX := Pt
.
Y - BR[beThumb].Top;
ThumbSize := BR[beThumb].Bottom - BR[beThumb].Top;
L := BR[beArrow1].Bottom;
H := BR[beArrow2].Top;
end
;
{ if nBarCode = SB_HORZ then SendMessage(hWnd, WM_SYSCOMMAND, SC_HSCROLL, MAKELPARAM(Pt.X, Pt.Y))
else SendMessage(hWnd, WM_SYSCOMMAND, SC_VSCROLL, MAKELPARAM(Pt.X, Pt.Y)); }
GetSkinSBInfo(hWnd)^.Tracking :=
True
;
UpdateDragBar(
True
);
try
SetCapture(hWnd);
while
GetCapture = hWnd
do
begin
if
not
GetMessage(Msg,
0
,
0
,
0
)
then
Break;
if
Msg
.
hwnd = hWnd
then
begin
case
Msg
.
message
of
WM_MOUSEMOVE:
begin
Pushed := ValidDragArea(R, Pt);
GetCursorPos(Pt);
ScreenToClient(hWnd, Pt);
if
ValidDragArea(R, Pt)
then
begin
Pos := CalcPos(R, Pt, DragX);
if
nBarCode = SB_HORZ
then
X := Pt
.
X - DragX
else
X := Pt
.
Y - DragX;
end
else
begin
Pos := SI
.
nPos;
X := DragX;
end
;
GetSkinSBInfo(hWnd)^.ThumbPos := Pos;
GetSkinSBInfo(hWnd)^.ThumbTrack :=
True
;
SendMessage(hWnd, ScrollMsg, MAKEWPARAM(SB_THUMBTRACK, Pos),
0
);
GetSkinSBInfo(hWnd)^.ThumbTrack :=
False
;
UpdateDragBar(Pushed, X);
end
;
WM_LBUTTONUP:
begin
GetCursorPos(Pt);
ScreenToClient(hWnd, Pt);
if
ValidDragArea(R, Pt)
then
begin
Pos := CalcPos(R, Pt, DragX);
SI2
.
cbSize := SizeOf(SI2);
SI2
.
fMask := SIF_ALL;
GetScrollInfo(hWnd, nBarCode, SI2);
SI2
.
nPos := Pos;
SI2
.
nTrackPos := Pos;
SetScrollInfo(hWnd, nBarCode, SI2,
False
);
SI2
.
nTrackPos :=
0
;
SI2
.
nPos :=
0
;
GetScrollInfo(hWnd, nBarCode, SI2);
SendMessage(hWnd, ScrollMsg, MAKEWPARAM(SB_THUMBPOSITION, Pos),
0
);
SendMessage(hWnd, ScrollMsg, SB_ENDSCROLL,
0
);
end
;
Break;
end
;
end
;
end
;
DispatchMessage(Msg);
end
;
finally
if
IsWindow(hWnd)
then
begin
if
GetCapture = hWnd
then
ReleaseCapture;
GetSkinSBInfo(hWnd)^.Tracking :=
False
;
end
;
UpdateDragBar(
False
);
end
;
end
;
function
SkinSBWndProc(hWnd: HWND; uMsg: UINT; wParam: WPARAM; lParam: LPARAM): LRESULT;
var
PInfo: PSkinSBInfo;
Style, ExStyle:
Cardinal
;
R, RHBar, RVBar, RCross: TRect;
Pt: TPoint;
Rgn, Rgn2: HRGN;
PR: PRect;
BR: TBarElemRects;
XBar, YBar:
Integer
;
begin
PInfo := GetSkinSBInfo(hWnd);
if
PInfo =
nil
then
Result := DefWindowProc(hWnd, uMsg, wParam, lParam)
//// error!!!
else
begin
case
uMsg
of
WM_NCHITTEST:
begin
GetCursorPos(Pt);
ScreenToClient(hWnd, Pt);
case
GetPtBarPos(hWnd, Pt)
of
bpcHArrowL:
begin
if
(GetKeyState(VK_LBUTTON)
and
$8000
) <>
0
then
begin
if
GetCapture <> hWnd
then
TrackBar(hWnd, SB_HORZ, bpcHArrowL, beArrow1, SB_LINELEFT);
end
;
Result := HTNOWHERE;
Exit;
end
;
bpcHArrowR:
begin
if
(GetKeyState(VK_LBUTTON)
and
$8000
) <>
0
then
begin
if
GetCapture <> hWnd
then
TrackBar(hWnd, SB_HORZ, bpcHArrowR, beArrow2, SB_LINERIGHT);
end
;
Result := HTNOWHERE;
Exit;
end
;
bpcHPageL:
begin
if
(GetKeyState(VK_LBUTTON)
and
$8000
) <>
0
then
begin
if
GetCapture <> hWnd
then
begin
TrackBar(hWnd, SB_HORZ, bpcHPageL, beBG, SB_PAGELEFT);
RedrawScrollBars(hWnd);
end
;
end
;
Result := HTNOWHERE;
Exit;
end
;
bpcHPageR:
begin
if
(GetKeyState(VK_LBUTTON)
and
$8000
) <>
0
then
begin
if
GetCapture <> hWnd
then
begin
TrackBar(hWnd, SB_HORZ, bpcHPageR, beBG, SB_PAGERIGHT);
RedrawScrollBars(hWnd);
end
;
end
;
Result := HTNOWHERE;
Exit;
end
;
bpcHThumb:
begin
if
(GetKeyState(VK_LBUTTON)
and
$8000
) <>
0
then
begin
if
GetCapture <> hWnd
then
TrackThumb(hWnd, SB_HORZ, bpcHThumb, beThumb);
end
;
Result := HTNOWHERE;
Exit;
end
;
bpcVArrowU:
begin
if
(GetKeyState(VK_LBUTTON)
and
$8000
) <>
0
then
begin
if
GetCapture <> hWnd
then
TrackBar(hWnd, SB_VERT, bpcVArrowU, beArrow1, SB_LINELEFT);
end
;
Result := HTNOWHERE;
Exit;
end
;
bpcVArrowD:
begin
if
(GetKeyState(VK_LBUTTON)
and
$8000
) <>
0
then
begin
if
GetCapture <> hWnd
then
TrackBar(hWnd, SB_VERT, bpcVArrowD, beArrow2, SB_LINERIGHT);
end
;
Result := HTNOWHERE;
Exit;
end
;
bpcVPageU:
begin
if
(GetKeyState(VK_LBUTTON)
and
$8000
) <>
0
then
begin
if
GetCapture <> hWnd
then
begin
TrackBar(hWnd, SB_VERT, bpcVPageU, beBG, SB_PAGELEFT);
RedrawScrollBars(hWnd);
end
;
end
;
Result := HTNOWHERE;
Exit;
end
;
bpcVPageD:
begin
if
(GetKeyState(VK_LBUTTON)
and
$8000
) <>
0
then
begin
if
GetCapture <> hWnd
then
begin
TrackBar(hWnd, SB_VERT, bpcVPageD, beBG, SB_PAGERIGHT);
RedrawScrollBars(hWnd);
end
;
end
;
Result := HTNOWHERE;
Exit;
end
;
bpcVThumb:
begin
if
(GetKeyState(VK_LBUTTON)
and
$8000
) <>
0
then
begin
if
GetCapture <> hWnd
then
TrackThumb(hWnd, SB_VERT, bpcVThumb, beThumb);
end
;
Result := HTNOWHERE;
Exit;
end
;
end
;
end
;
WM_HSCROLL:
begin
PInfo^.Scrolling :=
True
;
Style := GetWindowLong(hWnd, GWL_STYLE);
PInfo^.Style := Style;
PInfo^.Prevent :=
True
;
try
SetWindowLong(hWnd, GWL_STYLE, Style
and
(
not
(WS_VSCROLL
or
WS_HSCROLL)));
finally
PInfo^.Prevent :=
False
;
end
;
Result := CallWindowProc(@PInfo^.OldWndProc, hWnd, uMsg, wParam, lParam);
RedrawScrollBars(hWnd);
PInfo^.Prevent :=
True
;
try
SetWindowLong(hWnd, GWL_STYLE, Style);
finally
PInfo^.Prevent :=
False
;
end
;
PInfo^.Scrolling :=
False
;
Exit;
end
;
WM_VSCROLL:
begin
PInfo^.Scrolling :=
True
;
Style := GetWindowLong(hWnd, GWL_STYLE);
PInfo^.Style := Style;
PInfo^.Prevent :=
True
;
try
SetWindowLong(hWnd, GWL_STYLE, Style
and
(
not
(WS_VSCROLL
or
WS_HSCROLL)));
finally
PInfo^.Prevent :=
False
;
end
;
Result := CallWindowProc(@PInfo^.OldWndProc, hWnd, uMsg, wParam, lParam);
PInfo^.Prevent :=
True
;
try
SetWindowLong(hWnd, GWL_STYLE, Style);
finally
PInfo^.Prevent :=
False
;
end
;
PInfo^.Scrolling :=
False
;
Exit;
end
;
WM_STYLECHANGED:
begin
if
wParam = GWL_STYLE
then
begin
if
PInfo^.Prevent
then
begin
Result :=
0
;
Exit;
end
else
begin
PInfo^.Style := GetWindowLong(hWnd, GWL_STYLE);
end
;
end
;
end
;
WM_NCCALCSIZE:
begin
Style := GetWindowLong(hWnd, GWL_STYLE);
ExStyle := GetWindowLong(hWnd, GWL_EXSTYLE);
XBar := GetSystemMetrics(SM_CXVSCROLL);
YBar := GetSystemMetrics(SM_CYHSCROLL);
if
PInfo^.Scrolling
then
begin
PInfo^.Prevent :=
True
;
try
SetWindowLong(hWnd, GWL_STYLE, Style
and
(
not
(WS_HSCROLL
or
WS_VSCROLL)));
// real style
finally
PInfo^.Prevent :=
False
;
end
;
end
;
Result := CallWindowProc(@PInfo^.OldWndProc, hWnd, uMsg, wParam, lParam);
if
PInfo^.Scrolling
then
begin
PR := PRect(lParam);
if
(PInfo^.Style
and
WS_VSCROLL) <>
0
then
begin
if
(ExStyle
and
WS_EX_LEFTSCROLLBAR) <>
0
then
Inc(PR^.Left, XBar)
else
Dec(PR^.Right, XBar);
end
;
if
(PInfo^.Style
and
WS_HSCROLL) <>
0
then
begin
Dec(PR^.Bottom, YBar);
end
;
end
;
if
PInfo^.Scrolling
then
begin
PInfo^.Prevent :=
True
;
try
SetWindowLong(hWnd, GWL_STYLE, Style);
// old style
finally
PInfo^.Prevent :=
False
;
end
;
end
;
Exit;
end
;
WM_NCPAINT:
begin
GetWindowRect(hWnd, R);
Pt := R
.
TopLeft;
if
wParam =
1
then
begin
Rgn := CreateRectRgn(Pt
.
X, Pt
.
Y, Pt
.
X + R
.
Right, Pt
.
Y + R
.
Bottom);
end
else
Rgn := wParam;
RHBar := CalcScrollBarRect(hWnd, SB_HORZ);
OffsetRect(RHBar, Pt
.
X, PT
.
Y);
if
not
IsRectEmpty(RHBar)
then
begin
BR := CalcBarElemRects(hWnd, SB_HORZ);
GetSkinSB
.
DrawElem(hWnd, bpcHPageL, Rect(BR[beBG].Left, BR[beBG].Top, BR[beThumb].Left, BR[beBG].Bottom),
False
);
GetSkinSB
.
DrawElem(hWnd, bpcHPageR, Rect(BR[beThumb].Right, BR[beBG].Top, BR[beBG].Right, BR[beBG].Bottom),
False
);
GetSkinSB
.
DrawElem(hWnd, bpcHThumb, BR[beThumb],
False
);
GetSkinSB
.
DrawElem(hWnd, bpcHArrowL, BR[beArrow1],
False
);
GetSkinSB
.
DrawElem(hWnd, bpcHArrowR, BR[beArrow2],
False
);
end
;
Rgn2 := CreateRectRgn(RHBar
.
Left, RHBar
.
Top, RHBar
.
Right, RHBar
.
Bottom);
CombineRgn(Rgn, Rgn, Rgn2, RGN_DIFF);
DeleteObject(Rgn2);
RVBar := CalcScrollBarRect(hWnd, SB_VERT);
if
not
IsRectEmpty(RVBar)
then
begin
BR := CalcBarElemRects(hWnd, SB_VERT);
GetSkinSB
.
DrawElem(hWnd, bpcVPageU, Rect(BR[beBG].Left, BR[beBG].Top, BR[beBG].Right, BR[beThumb].Top),
False
);
GetSkinSB
.
DrawElem(hWnd, bpcVPageD, Rect(BR[beBG].Left, BR[beThumb].Bottom, BR[beBG].Right, BR[beBG].Bottom),
False
);
GetSkinSB
.
DrawElem(hWnd, bpcVThumb, BR[beThumb],
False
);
GetSkinSB
.
DrawElem(hWnd, bpcVArrowU, BR[beArrow1],
False
);
GetSkinSB
.
DrawElem(hWnd, bpcVArrowD, BR[beArrow2],
False
);
end
;
OffsetRect(RVBar, Pt
.
X, PT
.
Y);
Rgn2 := CreateRectRgn(RVBar
.
Left, RVBar
.
Top, RVBar
.
Right, RVBar
.
Bottom);
CombineRgn(Rgn, Rgn, Rgn2, RGN_DIFF);
DeleteObject(Rgn2);
RCross := CalcScrollBarRect(hWnd, SB_BOTH);
if
not
IsRectEmpty(RCross)
then
begin
GetSkinSB
.
DrawElem(hWnd, bpcCross, RCross,
False
);
end
;
OffsetRect(RCross, Pt
.
X, PT
.
Y);
Rgn2 := CreateRectRgn(RCross
.
Left, RCross
.
Top, RCross
.
Right, RCross
.
Bottom);
CombineRgn(Rgn, Rgn, Rgn2, RGN_DIFF);
DeleteObject(Rgn2);
Result := CallWindowProc(@PInfo^.OldWndProc, hWnd, uMsg, Rgn, lParam);
if
wParam =
1
then
DeleteObject(Rgn);
Exit;
end
;
WM_ERASEBKGND:
begin
Style := GetWindowLong(hWnd, GWL_STYLE);
PInfo^.Prevent :=
True
;
try
SetWindowLong(hWnd, GWL_STYLE, Style
and
(
not
(WS_VSCROLL
or
WS_HSCROLL)));
finally
PInfo^.Prevent :=
False
;
end
;
Result := CallWindowProc(@PInfo^.OldWndProc, hWnd, uMsg, wParam, lParam);
PInfo^.Prevent :=
True
;
try
SetWindowLong(hWnd, GWL_STYLE, Style);
// old style
finally
PInfo^.Prevent :=
False
;
end
;
Exit;
end
;
WM_MOUSEWHEEL, WM_MOUSEMOVE:
begin
Result := CallWindowProc(@PInfo^.OldWndProc, hWnd, uMsg, wParam, lParam);
if
PInfo^.Tracking
then
Exit;
if
(uMsg = WM_MOUSEMOVE)
and
((wParam
and
MK_LBUTTON) =
0
)
then
Exit;
RedrawScrollBars(hWnd);
Exit;
end
;
end
;
Result := CallWindowProc(@PInfo^.OldWndProc, hWnd, uMsg, wParam, lParam);
end
;
end
;
initialization
l_SkinSB :=
nil
;
l_SkinSB_Prop := GlobalAddAtom(SKINSB_PROP);
finalization
if
Assigned(l_SkinSB)
then
FreeAndNil(l_SkinSB);
end
.
|
补充：使用此方法后，在调用SetScrollInfo后也必须调用RedrawScrollBars重绘滚动条。Hook本模块的SetScrollInfo API是个好方法。在这里就不给出代码了。
学习中的点点滴滴予以记载，以便以后的学习复习。 本篇博客转自Lucky2011的博客(http://www.cnblogs.com/Lucky2011/)
http://www.cnblogs.com/Lucky2011/archive/2011/04/01/2002131.html
关于ListView 设置OwnerData 为 True时 Items删除节点不起作用
当ListView 设置OwnerData := True 时，再调用ListView.Items.delete(I)，是不起作用的。
在使用很多方法和查询资料的方法的也没有解决这个问题。
但是在我仔细研究listView源码后发现可以利用消息的方法删除某个节点，SendMessage(hWnd, LVM_DELETEITEM, i, 0);
在CommCtrl单元里面封装好了对listView的所有消息的的接口；
本例用到的接口如下：
function ListView_DeleteItem(hWnd: HWND; i: Integer): Bool;
学习中的点点滴滴予以记载，以便以后的学习复习。 本篇博客转自Lucky2011的博客(http://www.cnblogs.com/Lucky2011/)
http://www.cnblogs.com/Lucky2011/archive/2011/04/06/2006554.html
