c++ - 将文本附加到窗口最终会停止添加文本 (Win32)
问题描述
我正在尝试将文本附加到子窗口中。在写了很多文本之后,没有附加任何内容。当文本停止附加时,我尝试捕获错误并遍历调试器,但没有什么不寻常的 - 调试器遍历代码并且不会添加任何文本,并且不会显示错误。
这是我的附加功能:
void AppendText(HWND hEditWnd, std::string Text) {
int idx = GetWindowTextLength(hEditWnd);
SetLastError(NOERROR);
SendMessage(hEditWnd, WM_SETFOCUS, (WPARAM)hEditWnd, 0);
SendMessage(hEditWnd, EM_SETSEL, (WPARAM) idx, (LPARAM) idx);
SendMessage(hEditWnd, EM_REPLACESEL, WPARAM(TRUE), (LPARAM) ((LPSTR) Text.c_str()));
ULONG dwErrorCode = GetLastError();
if (dwErrorCode != NOERROR)
{
printf("fail with %u error\n", dwErrorCode);
}
}
这是一些示例代码来尝试一下。为了延迟函数调用,我放置了一个 for 循环让程序继续运行。约 30 秒后,文本将停止附加到窗口。
#include <windows.h>
#include <tchar.h>
#include <string>
#include <windowsx.h>
#define ID_GO 1
#define ID_GO_ONCE 2
const char g_szClassName[] = "myWindowClass";
HWND hOut;
void AppendText(HWND hEditWnd, std::string Text) {
int idx = GetWindowTextLength(hEditWnd);
SetLastError(NOERROR);
SendMessage(hEditWnd, WM_SETFOCUS, (WPARAM)hEditWnd, 0);
SendMessage(hEditWnd, EM_SETSEL, (WPARAM) idx, (LPARAM) idx);
SendMessage(hEditWnd, EM_REPLACESEL, WPARAM(TRUE), (LPARAM) ((LPSTR) Text.c_str()));
ULONG dwErrorCode = GetLastError();
if (dwErrorCode != NOERROR)
{
printf("fail with %u error\n", dwErrorCode);
}
}
LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
switch(msg)
{
case WM_CREATE:
{
HMENU hMenu, hSubMenu;
hMenu = CreateMenu();
hSubMenu = CreatePopupMenu();
AppendMenu(hSubMenu, MF_STRING, ID_GO_ONCE, "&Go Once");
AppendMenu(hSubMenu, MF_STRING, ID_GO, "&Go");
AppendMenu(hMenu, MF_STRING | MF_POPUP, (UINT)hSubMenu, "&Output");
SetMenu(hwnd, hMenu);
}
break;
case WM_COMMAND:
switch(LOWORD(wParam))
{
case ID_GO_ONCE:
AppendText(hOut, "-----HELLO-----\r\n");
AppendText(hOut, "-----TEST-----\r\n");
break;
case ID_GO:
while(1) {
AppendText(hOut, "-----HELLO-----\r\n");
for(int q = 0; q < 7000000; q++);
AppendText(hOut, "-----TEST-----\r\n");
for(int q = 0; q < 7000000; q++);
}
break;
}
break;
case WM_CLOSE:
DestroyWindow(hwnd);
break;
case WM_DESTROY:
PostQuitMessage(0);
break;
default:
return DefWindowProc(hwnd, msg, wParam, lParam);
}
return 0;
}
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
LPSTR lpCmdLine, int nCmdShow)
{
WNDCLASSEX wc;
HWND hwnd;
MSG Msg;
wc.cbSize = sizeof(WNDCLASSEX);
wc.style = 0;
wc.lpfnWndProc = WndProc;
wc.cbClsExtra = 0;
wc.cbWndExtra = 0;
wc.hInstance = hInstance;
wc.hIcon = LoadIcon(NULL, IDI_APPLICATION);
wc.hCursor = LoadCursor(NULL, IDC_ARROW);
wc.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
wc.lpszMenuName = NULL;
wc.lpszClassName = g_szClassName;
wc.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
if(!RegisterClassEx(&wc))
{
MessageBox(NULL, "Window Registration Failed!", "Error!",
MB_ICONEXCLAMATION | MB_OK);
return 0;
}
hwnd = CreateWindowEx(
WS_EX_CLIENTEDGE,
g_szClassName,
"Test GUI",
WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT, CW_USEDEFAULT, 680, 402,
NULL, NULL, hInstance, NULL);
if(hwnd == NULL)
{
MessageBox(NULL, "Window Creation Failed!", "Error!",
MB_ICONEXCLAMATION | MB_OK);
return 0;
}
hOut = CreateWindowW(L"Edit", L"", WS_CHILD | WS_VISIBLE | ES_LEFT | ES_MULTILINE |
ES_AUTOHSCROLL | ES_AUTOVSCROLL, 0, 0, 680 - 20, 340, hwnd, NULL, NULL, NULL);
ShowWindow(hwnd, nCmdShow);
UpdateWindow(hwnd);
while(GetMessage(&Msg, NULL, 0, 0) > 0)
{
TranslateMessage(&Msg);
DispatchMessage(&Msg);
}
return Msg.wParam;
}
一个窗口可以显示多少文本有限制吗?
解决方案
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