关于滚动条的问题
滚动条滚动后程序界面内容错乱了，不知道为何会这样
大家帮忙看看代码
#include<Windows.h>
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, PSTR szCmdLine, int iCmdShow)
{
static TCHAR szAppName[] = TEXT("MyWindows");
HWND hwnd;
MSG msg;
WNDCLASS wndclass;
wndclass.style = CS_HREDRAW | CS_VREDRAW;
wndclass.lpfnWndProc = WndProc;
wndclass.cbClsExtra = 0;
wndclass.cbWndExtra = 0;
wndclass.hInstance = hInstance;
wndclass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
wndclass.hCursor = LoadCursor(NULL, IDC_ARROW);
wndclass.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
wndclass.lpszMenuName = NULL;
wndclass.lpszClassName = szAppName;
if (!RegisterClass(&wndclass))
{
MessageBox(NULL, TEXT("this program requires Windows NT!"), szAppName, MB_ICONERROR);
return 0;
}
hwnd = CreateWindow(szAppName,
TEXT("by:"),
WS_OVERLAPPEDWINDOW |WS_VSCROLL,
CW_USEDEFAULT,
CW_USEDEFAULT,
500,
400,
NULL,
NULL,
hInstance,
NULL
);
ShowWindow(hwnd, iCmdShow);
UpdateWindow(hwnd);
while (GetMessage(&msg, NULL, 0, 0))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
return msg.wParam;
}
LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
HDC hdc;
PAINTSTRUCT ps;
SCROLLINFO si;
TEXTMETRICW tm;
TCHAR szBuffer;
static int cxClient, cyClient,cxchar,cychar,iVertPos;
switch (message)
{
case WM_SIZE:
cxClient = LOWORD(lParam);
cyClient = HIWORD(lParam);
si.cbSize = sizeof(si);
si.fMask = SIF_RANGE | SIF_PAGE;
si.nMin = 0;
si.nMax = 30 - 1;
si.nPage = cyClient / cychar;
SetScrollInfo(hwnd, SB_VERT, &si, TRUE);
return 0;
case WM_VSCROLL:
si.cbSize = sizeof(si);
si.fMask = SIF_ALL;
GetScrollInfo(hwnd, SB_VERT, &si);
iVertPos = si.nPos;
switch (LOWORD(wParam))
{
case SB_LINEDOWN:
si.nPos = si.nPos + 1;
break;
case SB_LINEUP:
si.nPos = si.nPos - 1;
break;
default:
break;
}
si.fMask = SIF_POS;
SetScrollInfo(hwnd, SB_VERT, &si, TRUE);
GetScrollInfo(hwnd, SB_VERT, &si);
if (si.nPos != iVertPos)
{
ScrollWindow(hwnd, 0, cychar*(iVertPos - si.nPos), NULL, NULL);
UpdateWindow(hwnd);
}
return 0;
case WM_CREATE:
hdc = GetDC(hwnd);
GetTextMetrics(hdc, &tm);
cxchar = tm.tmAveCharWidth;
cychar = tm.tmHeight + tm.tmExternalLeading;
ReleaseDC(hwnd, hdc);
return 0;
case WM_PAINT:
hdc = BeginPaint(hwnd, &ps);
si.cbSize = sizeof(si);
si.fMask = SIF_POS;
GetScrollInfo(hwnd, SB_VERT, &si);
iVertPos = si.nPos;
for (int i = 0; i < 30; i++)
{
wsprintf(szBuffer, TEXT("%d"), i);
TextOut(hdc, 0, i*cychar, szBuffer, lstrlen(szBuffer));
}
EndPaint(hwnd, &ps);
return 0;
case WM_DESTROY:
PostQuitMessage(0);
return 0;
}
return DefWindowProc(hwnd, message, wParam, lParam);
} 朋友不妨可以参考下咱课堂上的演示代码：
/* -------------------------------------------------------------------
MyWindows.c -- 基本窗口模型
《Windows 程序设计（SDK）》视频教程
--------------------------------------------------------------------*/
#include <windows.h>
#include "strsafe.h"
#include "sysmets.h"
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, PSTR szCmdLine, int iCmdShow)
{
static TCHAR szAppName[] = TEXT("MyWindows");
HWND hwnd;
MSG msg;
WNDCLASS wndclass;
wndclass.style = CS_HREDRAW | CS_VREDRAW;
wndclass.lpfnWndProc = WndProc;
wndclass.cbClsExtra = 0;
wndclass.cbWndExtra = 0;
wndclass.hInstance = hInstance;
wndclass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
wndclass.hCursor = LoadCursor(NULL, IDC_ARROW);
wndclass.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
wndclass.lpszMenuName = NULL;
wndclass.lpszClassName = szAppName;
if (!RegisterClass(&wndclass))
{
MessageBox(NULL, TEXT("这个程序需要在 Windows NT 才能执行！"), szAppName, MB_ICONERROR);
return 0;
}
hwnd = CreateWindow(szAppName,
TEXT("鱼C工作室"),
WS_OVERLAPPEDWINDOW | WS_VSCROLL | WS_HSCROLL,
CW_USEDEFAULT,
CW_USEDEFAULT,
CW_USEDEFAULT,
CW_USEDEFAULT,
NULL,
NULL,
hInstance,
NULL);
ShowWindow(hwnd, iCmdShow);
UpdateWindow(hwnd);
while (GetMessage(&msg, NULL, 0, 0))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
return msg.wParam;
}
LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
HDC hdc;
PAINTSTRUCT ps;
TEXTMETRIC tm;
SCROLLINFO si;
TCHAR szBuffer;
static int cxChar, cxCaps, cyChar, cxClient, cyClient, iMaxWidth;
size_t iTarget;
int i, x, y, iVertPos, iHorzPos, iPaintBeg, iPaintEnd;
switch (message)
{
case WM_CREATE:
hdc = GetDC(hwnd);
GetTextMetrics(hdc, &tm);
cxChar = tm.tmAveCharWidth;
cxCaps = (tm.tmPitchAndFamily & 1 ? 3 : 2) * cxChar / 2;
cyChar = tm.tmHeight + tm.tmExternalLeading;
ReleaseDC(hwnd, hdc);
// 设置客户区的最大宽度
// （我们这里设置为 22 个大写字符的宽度 + 40 个小写字符的宽度）
iMaxWidth = 22 * cxCaps + 40 * cxChar;
return 0;
case WM_SIZE:
cxClient = LOWORD(lParam);
cyClient = HIWORD(lParam);
// 设置垂直滚动条
si.cbSize = sizeof(si);
si.fMask = SIF_RANGE | SIF_PAGE;
si.nMin = 0;
si.nMax = NUMLINES - 1;
si.nPage = cyClient / cyChar;
SetScrollInfo(hwnd, SB_VERT, &si, TRUE);
// 设置水平滚动条
si.cbSize = sizeof(si);
si.fMask = SIF_RANGE | SIF_PAGE;
si.nMin = 0;
si.nMax = 2 + iMaxWidth / cxChar;
si.nPage = cxClient / cxChar;
SetScrollInfo(hwnd, SB_HORZ, &si, TRUE);
return 0;
case WM_VSCROLL:
// 获得滚动条信息
si.cbSize = sizeof(si);
si.fMask = SIF_ALL;
GetScrollInfo(hwnd, SB_VERT, &si);
// 获得滑块的位置
iVertPos = si.nPos;
// 根据消息的通知码改变滚动条滑块的位置
switch (LOWORD(wParam))
{
// 用户点击键盘 Home 按键
case SB_TOP:
si.nPos = si.nMin;
break;
// 用户点击键盘 End 按键
case SB_BOTTOM:
si.nPos = si.nMax;
break;
// 用户点击滚动条上边的三角形
case SB_LINEUP:
si.nPos -= 1;
break;
// 用户点击滚动条下边的三角形
case SB_LINEDOWN:
si.nPos += 1;
break;
// 用户点击滑块上边的滚动条轴
case SB_PAGEUP:
si.nPos -= si.nPage;
break;
// 用户点击滑块下边的滚动条轴
case SB_PAGEDOWN:
si.nPos += si.nPage;
break;
// 用户拖动滚动条
case SB_THUMBTRACK:
si.nPos = si.nTrackPos;
break;
default:
break;
}
// 设置改变后的滚动条滑块位置
si.fMask = SIF_POS;
SetScrollInfo(hwnd, SB_VERT, &si, TRUE);
// 获得滚动条滑块的位置，由于窗口调整，它可能不是同一个值
GetScrollInfo(hwnd, SB_VERT, &si);
// 与此前的保存的值进行比较，如果不同则滚动窗口
if (si.nPos != iVertPos)
{
ScrollWindow(hwnd, 0, cyChar * (iVertPos - si.nPos), NULL, NULL);
UpdateWindow(hwnd);
}
return 0;
case WM_HSCROLL:
// 获得滚动条信息
si.cbSize = sizeof(si);
si.fMask = SIF_ALL;
GetScrollInfo(hwnd, SB_HORZ, &si);
// 获得滑块的位置
iHorzPos = si.nPos;
// 根据消息的通知码改变滚动条滑块的位置
switch (LOWORD(wParam))
{
// 用户点击滚动条左边的三角形
case SB_LINELEFT:
si.nPos -= 1;
break;
// 用户点击滚动条右边的三角形
case SB_LINERIGHT:
si.nPos += 1;
break;
// 用户点击滑块左边的滚动条轴
case SB_PAGELEFT:
si.nPos -= si.nPage;
break;
// 用户点击滑块右边的滚动条轴
case SB_PAGERIGHT:
si.nPos += si.nPage;
break;
// 滚动条最终停留的位置
case SB_THUMBPOSITION:
si.nPos = si.nTrackPos;
break;
default:
break;
}
// 设置改变后的滚动条滑块位置
si.fMask = SIF_POS;
SetScrollInfo(hwnd, SB_HORZ, &si, TRUE);
// 获得滚动条滑块的位置，由于窗口调整，它可能不是同一个值
GetScrollInfo(hwnd, SB_HORZ, &si);
// 与此前的保存的值进行比较，如果不同则滚动窗口
if (si.nPos != iHorzPos)
{
ScrollWindow(hwnd, cxChar * (iHorzPos - si.nPos), 0, NULL, NULL);
}
return 0;
case WM_PAINT:
hdc = BeginPaint(hwnd, &ps);
// 获得垂直滚动条的位置
si.cbSize = sizeof (si);
si.fMask = SIF_POS;
GetScrollInfo(hwnd, SB_VERT, &si);
iVertPos = si.nPos;
// 获得水平滚动条的位置
GetScrollInfo(hwnd, SB_HORZ, &si);
iHorzPos = si.nPos;
// 计算需要重绘的区域并确保范围在之中
iPaintBeg = max(0, iVertPos + ps.rcPaint.top / cyChar);
iPaintEnd = min(NUMLINES - 1, iVertPos + ps.rcPaint.bottom / cyChar);
for (i = iPaintBeg; i <= iPaintEnd; i++)
{
// 计算此时重绘无效区域的位置
x = cxChar * (1 - iHorzPos);
y = cyChar * (i - iVertPos);
StringCchLength(sysmetrics.szLabel, 1024, &iTarget);
TextOut(hdc, x, y, sysmetrics.szLabel, iTarget);
StringCchLength(sysmetrics.szDesc, 1024, &iTarget);
TextOut(hdc, x + 22 * cxCaps, y, sysmetrics.szDesc, iTarget);
SetTextAlign(hdc, TA_RIGHT | TA_TOP);
StringCchPrintf(szBuffer, 10, TEXT("%5d"), GetSystemMetrics(sysmetrics.iIndex));
StringCchLength(szBuffer, 10, &iTarget);
TextOut(hdc, x + 22 * cxCaps + 40 * cxChar, y, szBuffer, iTarget);
SetTextAlign(hdc, TA_LEFT | TA_TOP);
}
EndPaint(hwnd, &ps);
return 0;
case WM_DESTROY:
PostQuitMessage(0);
return 0;
}
return DefWindowProc(hwnd, message, wParam, lParam);
} 首先，你使用ScrollWindow函数时就要告诉自己，不要在滚动时重绘整个客户区。
这个函数只会产生一小块无效区域（存放在ps.rcPaint中），你要做的是在这块区域里面绘制。
所以你要用到ps.rcPaint这个矩形。代码修改的部分我标记出来了，和小甲鱼老师给的代码的核心是一样的，自己多想想，实在是百度都找不到的就回帖问问。
#include<Windows.h>
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, PSTR szCmdLine, int iCmdShow)
{
static TCHAR szAppName[] = TEXT("MyWindows");
HWND hwnd;
MSG msg;
WNDCLASS wndclass;
wndclass.style = CS_HREDRAW | CS_VREDRAW;
wndclass.lpfnWndProc = WndProc;
wndclass.cbClsExtra = 0;
wndclass.cbWndExtra = 0;
wndclass.hInstance = hInstance;
wndclass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
wndclass.hCursor = LoadCursor(NULL, IDC_ARROW);
wndclass.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
wndclass.lpszMenuName = NULL;
wndclass.lpszClassName = szAppName;
if (!RegisterClass(&wndclass))
{
MessageBox(NULL, TEXT("this program requires Windows NT!"), szAppName, MB_ICONERROR);
return 0;
}
hwnd = CreateWindow(szAppName,
TEXT("by:"),
WS_OVERLAPPEDWINDOW | WS_VSCROLL,
CW_USEDEFAULT,
CW_USEDEFAULT,
500,
400,
NULL,
NULL,
hInstance,
NULL
);
ShowWindow(hwnd, iCmdShow);
UpdateWindow(hwnd);
while (GetMessage(&msg, NULL, 0, 0))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
return msg.wParam;
}
LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
HDC hdc;
PAINTSTRUCT ps;
SCROLLINFO si;
TEXTMETRICW tm;
TCHAR szBuffer;
static int cxClient, cyClient, cxchar, cychar, iVertPos;
static RECT ScrollRect;
int FirstLine, LastLine;
switch (message)
{
case WM_SIZE:
cxClient = LOWORD(lParam);
cyClient = HIWORD(lParam);
GetClientRect(hwnd, &ScrollRect);
si.cbSize = sizeof(si);
si.fMask = SIF_RANGE | SIF_PAGE;
si.nMin = 0;
si.nMax = 30 - 1;
si.nPage = cyClient / cychar;
SetScrollInfo(hwnd, SB_VERT, &si, TRUE);
return 0;
case WM_VSCROLL:
si.cbSize = sizeof(si);
si.fMask = SIF_ALL;
GetScrollInfo(hwnd, SB_VERT, &si);
iVertPos = si.nPos;
switch (LOWORD(wParam))
{
case SB_LINEDOWN:
si.nPos = si.nPos + 1;
break;
case SB_LINEUP:
si.nPos = si.nPos - 1;
break;
default:
break;
}
si.fMask = SIF_POS;
SetScrollInfo(hwnd, SB_VERT, &si, TRUE);
GetScrollInfo(hwnd, SB_VERT, &si);
if (si.nPos != iVertPos)
{
ScrollWindow(hwnd, 0, cychar*(iVertPos - si.nPos), NULL, NULL);
UpdateWindow(hwnd);
}
return 0;
case WM_CREATE:
hdc = GetDC(hwnd);
GetTextMetrics(hdc, &tm);
cxchar = tm.tmAveCharWidth;
cychar = tm.tmHeight + tm.tmExternalLeading;
ReleaseDC(hwnd, hdc);
return 0;
case WM_PAINT:
hdc = BeginPaint(hwnd, &ps);
si.cbSize = sizeof(si);
si.fMask = SIF_ALL;
GetScrollInfo(hwnd, SB_VERT, &si);
iVertPos = si.nPos;
FirstLine = min(0, ps.rcPaint.top / cychar + iVertPos);
LastLine = max(29, ps.rcPaint.bottom / cychar + iVertPos); //控制从第几行开始绘制，在第几行结束绘制
for (int i = FirstLine; i <= LastLine; i++)
{
wsprintf(szBuffer, TEXT("%d"), i);
TextOut(hdc, 0, (i-iVertPos)*cychar, szBuffer, lstrlen(szBuffer));
}
EndPaint(hwnd, &ps);
return 0;
case WM_DESTROY:
PostQuitMessage(0);
return 0;
}
return DefWindowProc(hwnd, message, wParam, lParam);
}
响应WM_PAINT时：
FirstLine = min(0, ps.rcPaint.top / cychar + iVertPos);
LastLine = max(29, ps.rcPaint.bottom / cychar + iVertPos); //控制从第几行开始绘制，在第几行结束绘制
for (int i = FirstLine; i <= LastLine; i++)
{
wsprintf(szBuffer, TEXT("%d"), i);
TextOut(hdc, 0, (i-iVertPos)*cychar, szBuffer, lstrlen(szBuffer));
}
虽然我都不懂为什么要(i-vertPos)而不是直接i*cychar
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