Win32 GetWindowText()函数获取各种文本示例

#include <windows.h>
#include "resource.h"
 
LRESULT CALLBACK WindowProcedure (HWND, UINT, WPARAM, LPARAM);

HINSTANCE hInst;
TCHAR szClassName[] = TEXT("getwintextDemo");

int WINAPI
WinMain (HINSTANCE hThisInstance,
         HINSTANCE hPrevInstance,
         LPSTR lpszArgument,
         int nFunsterStil)
{
    HWND hwnd;
    MSG messages;
    WNDCLASSEX wincl;
 
	hInst = hThisInstance;
	
    wincl.hInstance = hThisInstance;
    wincl.lpszClassName = szClassName;
    wincl.lpfnWndProc = WindowProcedure;
    wincl.style = CS_DBLCLKS;
    wincl.cbSize = sizeof (WNDCLASSEX);
 
    wincl.hIcon = LoadIcon (NULL, IDI_APPLICATION);
    wincl.hIconSm = LoadIcon (NULL, IDI_APPLICATION);
    wincl.hCursor = LoadCursor (NULL, IDC_ARROW);
    wincl.lpszMenuName = MAKEINTRESOURCE (IDC_GETWINTEXTDEMO);
    wincl.cbClsExtra = 0;
    wincl.cbWndExtra = 0;
    wincl.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
 
    if (!RegisterClassEx (&wincl))
        return 0;
 
    hwnd = CreateWindowEx (
           0,
           szClassName,
           TEXT("getwintextDemo"),
           WS_OVERLAPPEDWINDOW,
           CW_USEDEFAULT,
           CW_USEDEFAULT,
           550,
           500,
           HWND_DESKTOP,
           NULL,
           hThisInstance,
           NULL
           );
 
    ShowWindow (hwnd, nFunsterStil);
 
    while (GetMessage (&messages, NULL, 0, 0))
    {
        TranslateMessage(&messages);
        DispatchMessage(&messages);
    }
 
    return messages.wParam;
}
 
LRESULT CALLBACK
WindowProcedure (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
	PAINTSTRUCT ps;
	HDC hdc;
	RECT rt;
	int ret;
	//HWND edit1 = 0, hbtn1=0; 有问题 
	HWND edit1, hbtn1;
	HWND hpad, hcalc;
	char szBuffer[100];
	char getbuf[100];
	int iLength;
				
    switch (message)
    {
			case WM_COMMAND:
    		switch (LOWORD(wParam))
    		{
			case IDM_Gettext:		
				hdc=GetDC(hwnd);		
				iLength=GetWindowTextLength(edit1);
				ret=GetWindowText(edit1,getbuf,iLength+1); //实际获取个数通过ret返回 
				//wsprintf(szBuffer, "%d",ret);
    			//MessageBox(NULL,szBuffer,TEXT("返回个数"),0);
				wsprintf(szBuffer, "文本框1的文本：%s",getbuf);
				TextOut(hdc,250,20,szBuffer,lstrlen(szBuffer));		
				
				iLength=GetWindowTextLength(hbtn1);
				ret=GetWindowText(hbtn1,getbuf,iLength); //实际获取个数通过ret返回
				//wsprintf(szBuffer, "%d",ret);
    			//MessageBox(NULL,szBuffer,TEXT("返回个数"),0);
				wsprintf(szBuffer, "按钮1的文本：%s",getbuf);
				TextOut(hdc,250,50,szBuffer,lstrlen(szBuffer));						
				
				GetWindowText(GetDlgItem(hwnd,8), getbuf, 30);
				wsprintf(szBuffer, "文本框1的文本：%s",getbuf);
				TextOut(hdc,250,80,szBuffer,lstrlen(szBuffer));
				
				GetWindowText(GetDlgItem(hwnd,9), getbuf, 30);
				wsprintf(szBuffer, "按钮1的文本：%s",getbuf);
				TextOut(hdc,250,110,szBuffer,lstrlen(szBuffer));
				
				GetWindowText(hwnd, getbuf, 30);
				wsprintf(szBuffer, "本程序窗口的文本：%s",getbuf);
				TextOut(hdc,250,140,szBuffer,lstrlen(szBuffer));	
				
				hpad=FindWindow("Notepad",NULL);
				//wsprintf(szBuffer, "%x",hpad);
    			//MessageBox(NULL,szBuffer,TEXT("记事本句柄"),0);
    			GetWindowText(hpad, getbuf, 30);
				wsprintf(szBuffer, "记事本窗口的文本：%s",getbuf);
				TextOut(hdc,250,170,szBuffer,lstrlen(szBuffer));
				hcalc=FindWindow(NULL,"计算器");
				//wsprintf(szBuffer, "%x",hcalc);
    			//MessageBox(NULL,szBuffer,TEXT("计算器句柄"),0);
    			GetWindowText(hcalc, getbuf, 30);
				wsprintf(szBuffer, "计算器窗口的文本：%s",getbuf);
				TextOut(hdc,250,200,szBuffer,lstrlen(szBuffer));
				break;
		    case IDM_ABOUT:
				MessageBox (hwnd, TEXT ("getwintextDemo v1.0\nCopyright (C) 2020\n by bo"),
                        TEXT ("getwintextDemo"), MB_OK | MB_ICONINFORMATION);
				break;
			case IDM_EXIT:
				DestroyWindow(hwnd);
				break;
			default:
				return DefWindowProc(hwnd, message, wParam, lParam);	    		
		    }
    		break;
  		case WM_CREATE:
			edit1 = CreateWindow(TEXT("Edit"), TEXT("Edit Control DEMO"), WS_CHILD|WS_VISIBLE|ES_LEFT|WS_BORDER|WS_EX_CLIENTEDGE , 
			20, 20, 130, 20, hwnd, (HMENU)8, hInst, NULL);
			SendMessage(edit1, WM_SETFONT, (WPARAM)GetStockObject(25), 0);
			hbtn1 = CreateWindow("Button", "按钮一 Demo", WS_VISIBLE | WS_CHILD | BS_PUSHBUTTON,  
    		20, 50, 120, 20, hwnd, (HMENU)9, hwnd, NULL); 

  			break;
    	case WM_PAINT:
			hdc = BeginPaint(hwnd, &ps);					
			GetClientRect(hwnd, &rt);				
			EndPaint(hwnd, &ps);
			break;
        case WM_DESTROY:
            PostQuitMessage (0);
            break;
        default:
            return DefWindowProc (hwnd, message, wParam, lParam);
    }
 
    return 0;
}

新建一个窗口工程；首先自己在程序里创建一个文本框和一个按钮；

然后分别获取：文本框1，按钮1，本程序窗口，系统自带记事本窗口，系统自带计算器窗口的文本；

结果如下；

如果这么获取文本框1的文本，并不能获取到；

    GetWindowText(edit1,getbuf,iLength+1)；

    按钮类似；输出如第1、2行；

必须要获取到子控件句柄，才能获取到；

    GetWindowText(GetDlgItem(hwnd,8), getbuf, 30);    //hwnd是本程序窗口句柄；

    输出如第3、4行；

然后再获取记事本和计算器的文本（标题）；运行程序需要打开一个记事本，一个计算器；

记事本句柄通过窗口类名获取；计算器句柄通过窗口标题获取；

    hpad=FindWindow("Notepad",NULL);

    hcalc=FindWindow(NULL,"计算器");

GetWindowText()函数参数：句柄，返回内容缓冲区，可填入缓冲区的最大个数；实际返回个数通过函数返回值获取；

可以先如此获取一个窗口文本的长度，再加1，用做GetWindowText()第三个参数；

     iLength=GetWindowTextLength(edit1);

注释了的这两句，是用来调试，如果有问题，返回个数为0；字符个数；

    wsprintf(szBuffer, "%d",ret);
    MessageBox(NULL,szBuffer,TEXT("返回个数"),0);

菜单；

工程；

资源和头文件；

#include "resource.h"
#include <windows.h>

/
//
// Menu
//

IDC_GETWINTEXTDEMO MENU 
BEGIN
    POPUP "&File"
    BEGIN
    	MENUITEM "获取窗口文本",            IDM_Gettext
    	MENUITEM "E&xit",                	IDM_EXIT
    END
    POPUP "&Help"
    BEGIN
        MENUITEM "&About ...",           	IDM_ABOUT
    END
END

#define 	IDM_EXIT		10001
#define 	IDM_ABOUT		10002

#define 	IDC_GETWINTEXTDEMO		10101
#define 	IDD_ABOUTBOX	10102
#define     IDM_Gettext     40001