自绘LISTVIEW的滚动条(Delphi实现)

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。

unit SkinSB;interfaceusesSysUtils, Classes, Windows, Messages, Graphics;constSKINSB_PROP = '{8BC6661E-5880-4353-878D-C3B3784CFC5F}';typeTBarPosCode = ( 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 recordOldWndProc: TWindowProc;Prevent: Boolean; // prevent style change messageScrolling: Boolean;Style: Cardinal; // real styleThumbTrack: Boolean;ThumbPos: Integer;Tracking: Boolean; // tracking: click arrow or track thumbend;TSkinSB = classprotectedFBitmap: TBitmap;constructor CreateInstance;publicconstructor 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;implementationusesCommCtrl;{$R *.res} varl_SkinSB: TSkinSB;l_SkinSB_Prop: TATOM;typePImageImportDescriptor = ^TImageImportDescriptor;TImageImportDescriptor = packed recordOriginalFirstThunk: DWORD;  // or Characteristics: DWORDTimeDateStamp: DWORD;ForwarderChain: DWORD;Name: DWORD;FirstThunk: DWORD;end;PImageChunkData = ^TImageChunkData;TImageChunkData = packed recordcase Integer of0: ( ForwarderString: DWORD );1: ( Func: DWORD );2: ( Ordinal: DWORD );3: ( AddressOfData: DWORD );end;PImageImportByName = ^TImageImportByName;TImageImportByName = packed recordHint: Word;Name: array[0..0] of Byte;end;typePHookRec = ^THookRec;THookRec = packed recordOldFunc: Pointer;NewFunc: Pointer;end;var_HookGetScrollInfo: THookRec; procedure HookApiInMod(ImageBase: Cardinal; ApiName: PChar; PHook: PHookRec);
varpidh: PImageDosHeader;pinh: PImageNtHeaders;pSymbolTable: PIMAGEDATADIRECTORY;piid: PIMAGEIMPORTDESCRIPTOR;pitd_org, pitd_1st: PImageChunkData;piibn: PImageImportByName;pAPIFunction: Pointer;written, oldAccess: DWORD;
beginif 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);repeatpitd_org := PImageChunkData(DWORD(ImageBase) + piid^.OriginalFirstThunk);pitd_1st := PImageChunkData(DWORD(ImageBase) + piid^.FirstThunk);repeatpiibn := PImageImportByName(DWORD(ImageBase) + LPDWORD(pitd_org)^);pAPIFunction := Pointer(pitd_1st^.Func);if StrComp(ApiName, @piibn^.Name) = 0 thenbeginPHook^.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;
beginResult := PSkinSBInfo( GetProp(hWnd, MAKEINTATOM(l_SkinSB_Prop)) );
end;function GetSkinSB: TSkinSB;
beginif l_SkinSB = nil then l_SkinSB := TSkinSB.CreateInstance;Result := l_SkinSB;
end;function CalcScrollBarRect(H: HWND; nBarCode: Cardinal): TRect;
varStyle, ExStyle: Cardinal;
beginSetRect(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) thenbeginInflateRect(Result, -GetSystemMetrics(SM_CXEDGE), -GetSystemMetrics(SM_CYEDGE));end;// special: returns the crossif nBarCode = SB_BOTH thenbeginif ((Style and WS_HSCROLL) = 0) or ((Style and WS_VSCROLL) = 0) thenbeginSetRect(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 thenbegin//    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 thenbeginif (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;typeTBarElem = (beArrow1, beBG, beThumb, beArrow2);TBarElemRects = array[TBarElem] of TRect;function CalcBarElemRects(hWnd: HWND; nBarCode: Integer): TBarElemRects;
varR: TRect;SI: TScrollInfo;ThumbSize: Integer;X, L, H, BlockH, BlockV: Integer;
beginR := 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 thenbeginBlockV := 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;endelsebeginBlockH := 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 thenbegin// max thumb, no thumbif nBarCode = SB_VERT thenbeginResult[beThumb].Top := L;Result[beThumb].Bottom := H;endelsebeginResult[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 thenbeginResult[beThumb].Top := X;Result[beThumb].Bottom := X + ThumbSize;endelsebeginResult[beThumb].Left := X;Result[beThumb].Right := X + ThumbSize;end;
end;function GetPtBarPos(H: HWND; Pt: TPoint): TBarPosCode;
varR: TRect;BR: TBarElemRects;
beginResult := bpcNone;R := CalcScrollBarRect(H, SB_HORZ);InflateRect(R, GetSystemMetrics(SM_CXEDGE), GetSystemMetrics(SM_CYEDGE));if PtInRect(R, Pt) thenbeginBR := CalcBarElemRects(H, SB_HORZ);if PtInRect(BR[beArrow1], Pt) then Result := bpcHArrowLelse if PtInRect(BR[beThumb], Pt) then Result := bpcHThumbelse if PtInRect(BR[beArrow2], Pt) then Result := bpcHArrowRelse if Pt.X < BR[beThumb].Left then Result := bpcHPageLelse Result := bpcHPageR;Exit;end;R := CalcScrollBarRect(H, SB_VERT);InflateRect(R, GetSystemMetrics(SM_CXEDGE), GetSystemMetrics(SM_CYEDGE)); if PtInRect(R, Pt) thenbeginBR := CalcBarElemRects(H, SB_VERT);if PtInRect(BR[beArrow1], Pt) then Result := bpcVArrowUelse if PtInRect(BR[beThumb], Pt) then Result := bpcVThumbelse if PtInRect(BR[beArrow2], Pt) then Result := bpcVArrowDelse if Pt.Y < BR[beThumb].Top then Result := bpcVPageUelse Result := bpcVPageD;Exit;end;
end;typeTGetScrollInfoFunc = function (H: HWND; Code: Integer; var SI: TScrollInfo): Boolean; stdcall;function _SkinSB_GetScrollInfo(H: HWND; Code: Integer; var SI: TScrollInfo): Boolean; stdcall;
varP: PSkinSBInfo;
beginResult := TGetScrollInfoFunc(_HookGetScrollInfo.OldFunc)(H, Code, SI);P := GetSkinSBInfo(H);if (P <> nil) and P^.ThumbTrack and ((SI.fMask and SIF_TRACKPOS) <> 0) thenbeginSI.nTrackPos := P^.ThumbPos;end;
end;{ TSkinSB }constructor TSkinSB.Create;
beginraise Exception.Create('use GetSkinSB.');
end;constructor TSkinSB.CreateInstance;
begininherited;_HookGetScrollInfo.OldFunc := nil;_HookGetScrollInfo.NewFunc := @_SkinSB_GetScrollInfo;HookApiInMod( GetModuleHandle('comctl32.dll'), 'GetScrollInfo', @_HookGetScrollInfo );FBitmap := TBitmap.Create;FBitmap.LoadFromResourceName(hInstance, 'scrollbar');
end;destructor TSkinSB.Destroy;
beginFreeAndNil(FBitmap);inherited;
end;procedure TSkinSB.DrawElem(H: HWND; Code: TBarPosCode; R: TRect;Down: Boolean);
varCanvas: TCanvas;
beginCanvas := TCanvas.Create;tryCanvas.Handle := GetWindowDC(H);trycase Code ofbpcHArrowL:beginif 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:beginif 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:beginBitBlt(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:beginif R.Right - R.Left < 4 thenbeginStretchBlt(Canvas.Handle, R.Left, R.Top, R.Right - R.Left, 16, FBitmap.Canvas.Handle,160, 0, 16, 16, SRCCOPY);endelsebeginBitBlt(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:beginif 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:beginif 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:beginBitBlt(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:beginif R.Bottom - R.Top < 4 thenbeginStretchBlt(Canvas.Handle, R.Left, R.Top, 16, R.Bottom - R.Top, FBitmap.Canvas.Handle,176, 0, 16, 16, SRCCOPY);endelsebeginBitBlt(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);finallyReleaseDC(H, Canvas.Handle);end;finallyCanvas.Handle := 0;FreeAndNil(Canvas);end;
end;procedure TSkinSB.InitSkinSB(H: HWND);
varPInfo: PSkinSBInfo;
beginPInfo := GetSkinSBInfo(H);if PInfo <> nil then Exit; // already initedNew(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);
varPInfo: PSkinSBInfo;
beginPInfo := GetSkinSBInfo(H);if PInfo = nil then Exit; // not initedRemoveProp(H, MAKEINTATOM(l_SkinSB_Prop));SetWindowLong(H, GWL_WNDPROC, Cardinal(@PInfo^.OldWndProc));Dispose(PInfo);
end;constWM_REPEAT_CLICK = WM_USER + $6478;procedure OnRepeatClickTimer(hWnd: HWND; uMsg: UINT; idEvent: UINT; dwTime: DWORD); stdcall;
beginKillTimer(0, idEvent);PostThreadMessage(MainThreadID, WM_REPEAT_CLICK, 0, 0);
end;procedure RedrawScrollBars(hWnd: HWND);
varRHBar, RVBar, RCross: TRect;BR: TBarElemRects;
beginRHBar := CalcScrollBarRect(hWnd, SB_HORZ);if not IsRectEmpty(RHBar) thenbeginBR := 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) thenbeginBR := 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) thenbeginGetSkinSB.DrawElem(hWnd, bpcCross, RCross, False);end;
end;procedure TrackBar(hWnd: HWND; nBarCode: Integer; PosCode: TBarPosCode; BarElem: TBarElem; MsgCode: Integer);
varBR: TBarElemRects;Msg: tagMSG;Pt: TPoint;R: TRect;ScrollMsg: Cardinal;RepeatClick: Boolean;idEvent: UINT;SI: TScrollInfo;procedure RefreshRect;beginBR := CalcBarElemRects(hWnd, nBarCode);R := BR[BarElem];end;beginRepeatClick := False;BR := CalcBarElemRects(hWnd, nBarCode);R := BR[BarElem];GetScrollInfo(hWnd, nBarCode, SI);if nBarCode = SB_HORZ then ScrollMsg := WM_HSCROLLelse ScrollMsg := WM_VSCROLL;if BarElem = beBG thenbeginif PosCode = bpcHPageL then R.Right := BR[beThumb].Leftelse if PosCode = bpcHPageR then R.Left := BR[beThumb].Rightelse if PosCode = bpcVPageU then R.Bottom := BR[beThumb].Topelse if PosCode = bpcVPageD then R.Top := BR[beThumb].Bottom;end;GetSkinSB.DrawElem(hWnd, PosCode, R, True);GetSkinSBInfo(hWnd)^.Tracking := True;idEvent := 0;trySetCapture(hWnd);idEvent := SetTimer(0, 0, 1000, @OnRepeatClickTimer);while GetCapture = hWnd dobeginif not GetMessage(Msg, 0, 0, 0) then Break;if (Msg.hwnd = 0) and (Msg.message = WM_REPEAT_CLICK) thenbeginGetCursorPos(Pt);ScreenToClient(hWnd, Pt);if PtInRect(R, Pt) thenbeginRepeatClick := 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;endelse if Msg.hwnd = hWnd thenbegincase Msg.message ofWM_LBUTTONUP:beginif RepeatClick then Break;GetCursorPos(Pt);ScreenToClient(hWnd, Pt);if PtInRect(R, Pt) thenbeginSendMessage(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;finallyif idEvent <> 0 then KillTimer(0, idEvent);if IsWindow(hWnd) thenbeginif 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);
varBR: 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;beginif nBarCode = SB_HORZ then Result := Abs((ARect.Bottom + ARect.Top) div 2 - APt.Y) < 150else Result := Abs((ARect.Left + ARect.Right) div 2 - APt.X) < 150;end;function CalcPos(ARect: TRect; APt: TPoint; ADragX: Integer): Integer;varNewX: Integer;beginif nBarCode = SB_HORZ then NewX := APt.X - ADragXelse 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 thenResult := SI.nMax - Integer(SI.nPage) + 1;end;procedure UpdateDragBar(ADown: Boolean; APos: Integer = -10000);varW: Integer;beginBR := CalcBarElemRects(hWnd, nBarCode);R := BR[BarElem];if nBarCode = SB_HORZ thenbeginif APos <> -10000 thenbeginW := 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);endelsebeginif APos <> -10000 thenbeginW := 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;beginBR := CalcBarElemRects(hWnd, nBarCode);R := BR[BarElem];if nBarCode = SB_HORZ then ScrollMsg := WM_HSCROLLelse ScrollMsg := WM_VSCROLL;SI.cbSize := SizeOf(SI);SI.fMask := SIF_ALL;GetScrollInfo(hWnd, nBarCode, SI);GetCursorPos(Pt);ScreenToClient(hWnd, Pt);if nBarCode = SB_HORZ thenbeginDragX := Pt.X - BR[beThumb].Left;ThumbSize := BR[beThumb].Right - BR[beThumb].Left;L := BR[beArrow1].Right;H := BR[beArrow2].Left;endelsebeginDragX := 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);trySetCapture(hWnd);while GetCapture = hWnd dobeginif not GetMessage(Msg, 0, 0, 0) then Break;if Msg.hwnd = hWnd thenbegincase Msg.message ofWM_MOUSEMOVE:beginPushed := ValidDragArea(R, Pt);GetCursorPos(Pt);ScreenToClient(hWnd, Pt);if ValidDragArea(R, Pt) thenbeginPos := CalcPos(R, Pt, DragX);if nBarCode = SB_HORZ then X := Pt.X - DragXelse X := Pt.Y - DragX;endelsebeginPos := 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:beginGetCursorPos(Pt);ScreenToClient(hWnd, Pt);if ValidDragArea(R, Pt) thenbeginPos := 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;finallyif IsWindow(hWnd) thenbeginif GetCapture = hWnd then ReleaseCapture;GetSkinSBInfo(hWnd)^.Tracking := False;end;UpdateDragBar(False);end;
end;function SkinSBWndProc(hWnd: HWND; uMsg: UINT; wParam: WPARAM; lParam: LPARAM): LRESULT;
varPInfo: PSkinSBInfo;Style, ExStyle: Cardinal;R, RHBar, RVBar, RCross: TRect;Pt: TPoint;Rgn, Rgn2: HRGN;PR: PRect;BR: TBarElemRects;XBar, YBar: Integer;
beginPInfo := GetSkinSBInfo(hWnd);if PInfo = nil then Result := DefWindowProc(hWnd, uMsg, wParam, lParam)  error!!!elsebegincase uMsg ofWM_NCHITTEST:beginGetCursorPos(Pt);ScreenToClient(hWnd, Pt);case GetPtBarPos(hWnd, Pt) ofbpcHArrowL:beginif (GetKeyState(VK_LBUTTON) and $8000) <> 0 thenbeginif GetCapture <> hWnd thenTrackBar(hWnd, SB_HORZ, bpcHArrowL, beArrow1, SB_LINELEFT);end;Result := HTNOWHERE;Exit;end;bpcHArrowR:beginif (GetKeyState(VK_LBUTTON) and $8000) <> 0 thenbeginif GetCapture <> hWnd thenTrackBar(hWnd, SB_HORZ, bpcHArrowR, beArrow2, SB_LINERIGHT);end;Result := HTNOWHERE;Exit;end;bpcHPageL:beginif (GetKeyState(VK_LBUTTON) and $8000) <> 0 thenbeginif GetCapture <> hWnd thenbeginTrackBar(hWnd, SB_HORZ, bpcHPageL, beBG, SB_PAGELEFT);RedrawScrollBars(hWnd);end;end;Result := HTNOWHERE;Exit;end;bpcHPageR:beginif (GetKeyState(VK_LBUTTON) and $8000) <> 0 thenbeginif GetCapture <> hWnd thenbeginTrackBar(hWnd, SB_HORZ, bpcHPageR, beBG, SB_PAGERIGHT);RedrawScrollBars(hWnd);end;end;Result := HTNOWHERE;Exit;end;bpcHThumb:beginif (GetKeyState(VK_LBUTTON) and $8000) <> 0 thenbeginif GetCapture <> hWnd thenTrackThumb(hWnd, SB_HORZ, bpcHThumb, beThumb);end;Result := HTNOWHERE;Exit;end;bpcVArrowU:beginif (GetKeyState(VK_LBUTTON) and $8000) <> 0 thenbeginif GetCapture <> hWnd thenTrackBar(hWnd, SB_VERT, bpcVArrowU, beArrow1, SB_LINELEFT);end;Result := HTNOWHERE;Exit;end;bpcVArrowD:beginif (GetKeyState(VK_LBUTTON) and $8000) <> 0 thenbeginif GetCapture <> hWnd thenTrackBar(hWnd, SB_VERT, bpcVArrowD, beArrow2, SB_LINERIGHT);end;Result := HTNOWHERE;Exit;end;bpcVPageU:beginif (GetKeyState(VK_LBUTTON) and $8000) <> 0 thenbeginif GetCapture <> hWnd thenbeginTrackBar(hWnd, SB_VERT, bpcVPageU, beBG, SB_PAGELEFT);RedrawScrollBars(hWnd);end;end;Result := HTNOWHERE;Exit;end;bpcVPageD:beginif (GetKeyState(VK_LBUTTON) and $8000) <> 0 thenbeginif GetCapture <> hWnd thenbeginTrackBar(hWnd, SB_VERT, bpcVPageD, beBG, SB_PAGERIGHT);RedrawScrollBars(hWnd);end;end;Result := HTNOWHERE;Exit;end;bpcVThumb:beginif (GetKeyState(VK_LBUTTON) and $8000) <> 0 thenbeginif GetCapture <> hWnd thenTrackThumb(hWnd, SB_VERT, bpcVThumb, beThumb);end;Result := HTNOWHERE;Exit;end;end;end;WM_HSCROLL:beginPInfo^.Scrolling := True;Style := GetWindowLong(hWnd, GWL_STYLE);PInfo^.Style := Style;PInfo^.Prevent := True;trySetWindowLong(hWnd, GWL_STYLE, Style and (not (WS_VSCROLL or WS_HSCROLL)));finallyPInfo^.Prevent := False;end;Result := CallWindowProc(@PInfo^.OldWndProc, hWnd, uMsg, wParam, lParam);RedrawScrollBars(hWnd);PInfo^.Prevent := True;trySetWindowLong(hWnd, GWL_STYLE, Style);finallyPInfo^.Prevent := False;end;PInfo^.Scrolling := False;Exit;end;WM_VSCROLL:beginPInfo^.Scrolling := True;Style := GetWindowLong(hWnd, GWL_STYLE);PInfo^.Style := Style;PInfo^.Prevent := True;trySetWindowLong(hWnd, GWL_STYLE, Style and (not (WS_VSCROLL or WS_HSCROLL)));finallyPInfo^.Prevent := False;end;Result := CallWindowProc(@PInfo^.OldWndProc, hWnd, uMsg, wParam, lParam);PInfo^.Prevent := True;trySetWindowLong(hWnd, GWL_STYLE, Style);finallyPInfo^.Prevent := False;end;PInfo^.Scrolling := False;Exit;end;WM_STYLECHANGED:beginif wParam = GWL_STYLE thenbeginif PInfo^.Prevent thenbeginResult := 0;Exit;endelsebeginPInfo^.Style := GetWindowLong(hWnd, GWL_STYLE);end;end;end;WM_NCCALCSIZE:beginStyle := GetWindowLong(hWnd, GWL_STYLE);ExStyle := GetWindowLong(hWnd, GWL_EXSTYLE);XBar := GetSystemMetrics(SM_CXVSCROLL);YBar := GetSystemMetrics(SM_CYHSCROLL);if PInfo^.Scrolling thenbeginPInfo^.Prevent := True;trySetWindowLong(hWnd, GWL_STYLE, Style and (not (WS_HSCROLL or WS_VSCROLL)));  // real stylefinallyPInfo^.Prevent := False;end;end;Result := CallWindowProc(@PInfo^.OldWndProc, hWnd, uMsg, wParam, lParam);if PInfo^.Scrolling thenbeginPR := PRect(lParam);if (PInfo^.Style and WS_VSCROLL) <> 0 thenbeginif (ExStyle and WS_EX_LEFTSCROLLBAR) <> 0 then Inc(PR^.Left, XBar)else Dec(PR^.Right, XBar);end;if (PInfo^.Style and WS_HSCROLL) <> 0 thenbeginDec(PR^.Bottom, YBar);end;end;if PInfo^.Scrolling thenbeginPInfo^.Prevent := True;trySetWindowLong(hWnd, GWL_STYLE, Style);  // old stylefinallyPInfo^.Prevent := False;end;end;Exit;end;WM_NCPAINT:beginGetWindowRect(hWnd, R);Pt := R.TopLeft;if wParam = 1 thenbeginRgn := 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) thenbeginBR := 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) thenbeginBR := 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) thenbeginGetSkinSB.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:beginStyle := GetWindowLong(hWnd, GWL_STYLE);PInfo^.Prevent := True;trySetWindowLong(hWnd, GWL_STYLE, Style and (not (WS_VSCROLL or WS_HSCROLL)));finallyPInfo^.Prevent := False;end;Result := CallWindowProc(@PInfo^.OldWndProc, hWnd, uMsg, wParam, lParam);PInfo^.Prevent := True;trySetWindowLong(hWnd, GWL_STYLE, Style);  // old stylefinallyPInfo^.Prevent := False;end;Exit;end;WM_MOUSEWHEEL, WM_MOUSEMOVE:beginResult := 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;initializationl_SkinSB := nil;l_SkinSB_Prop := GlobalAddAtom(SKINSB_PROP);finalizationif 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。

转载于:https://www.cnblogs.com/Lucky2011/archive/2011/04/01/2002131.html

自绘LISTVIEW的滚动条(Delphi实现)相关推荐

Android重绘ListView高度
Android重绘ListView高度经常会有这样需求,需要ListView默认将所有的条目显示出来,这就需要外层使用ScrollView,ScrollView里面放置一个重绘高度的ListView ...
android listview 不重绘,重绘listview
重绘listview (2010-04-28 11:19:31) 标签: 杂谈分类: C# 要实现ListView的各行各列重绘是一件很麻烦的事情,最近就确定要实现一个功能需求,在一个ListVie ...
【Android】自定义listview快速滚动条
2019独角兽企业重金招聘Python工程师标准>>> http://blog.csdn.net/xyang81/article/details/17680333 在eoe上看到有个 ...
横向ListView（四） —— 添加滚动条
2019独角兽企业重金招聘Python工程师标准>>> 在前面的文章已经介绍了横向ListView的基础实现及头尾视图的添加等的实现,这篇文章将介绍为横向ListView添加滚动条: ...
使用ListView应该注意的地方很全
在ListView中设置Selector为null会报空指针? mListView.setSelector(null);//空指针试试下面这种: mListView.setSelector(ne ...
揭秘换肤技术：实现系统滚动条换肤功能
对于Windows系统中各种控件换肤功能,要数滚动条的换肤最难实现了,尤其是控件自带的系统滚动条,如Edit.ListBox.ListView.TreeView等自带的系统滚动条,要想实现其自定义的皮 ...
实现系统滚动条换肤功能
对于Windows系统中各种控件换肤功能,要数滚动条的换肤最难实现了,尤其是控件自带的系统滚动条,如Edit.ListBox.ListView.TreeView等自带的系统滚动条,要想实现其自定义的皮 ...
android listview divider color,android listview 属性
1. 背景色: listView设置背景色android:background="@drawable/bg",拖动或者点击list空白位置的时候发现ListItem都变成黑色. 因 ...
ListView使用技巧-更新中
虽然在Android5.X中,RecyclerView在很多地方组件取代了ListView,但是ListView的使用依然是分广泛. 本博文将对以下两方面的内容进行介绍 1. ListView常用技巧 ...
Andorid ListView使用技巧
一.使用ViewHolder模式提高效率 ViewHolder模式充分利用ListView的视图缓存机制,避免了每次在调用getView()方法的时候都去通过findViewById()方法实例化控件 ...

自绘LISTVIEW的滚动条(Delphi实现)

自绘LISTVIEW的滚动条(Delphi实现)相关推荐

最新文章

热门文章