c++ - WinAPI 从编辑控件中检索文本

Question

这个问题已经让我抓狂了

我已经阅读了关于这个主题的每一个问答，每个人都有相同的解决方案，但它永远不会为我工作。我得出的结论是，因为我是新手，所以我一定遗漏了一些其他答案中没有提到的非常明显的东西，所以请尽可能详细地回答。

我有一个使用 WinAPI 的 C++ 程序。我有一个名为 hwnd 的窗口，该窗口有 2 个按钮和 2 个编辑控件文本框。此时我要做的就是将文本框中输入的文本保存到 .txt 文件中。

各种回答(还有微软官网)都说要用

SendMessage(editcontroltag，WM_GETTEXT，0，LPARAM 缓冲区)

或GetWindowText(editcontroltag, buffer, size)

等等。我已经尝试了所有这些，并且代码编译没有问题，但是我永远无法真正检索文本框中的文本。它要么是空的，要么是一些乱码(我试过 unicode 和 ansi，两种方式都会发生同样的事情)

乱码通常看起来像 ')6 或它的一些变体(它对我没有意义，所以我无法确定它的来源。

我尝试将缓冲区转换为几乎所有允许的数据类型，我尝试检索缓冲区及其地址(地址显示正常)。仍然没有运气。

我会在这里为您粘贴代码，很抱歉它非常困惑，您会注意到我已经注释掉了许多不同的检索文本的尝试。无论哪种方式都没有结果。每次都出现同样的错误

谢谢

#include <windows.h>
#include <iostream>
#include <fstream>
#include <TCHAR.H>
#include <stdio.h>
//#include "C:\Users\Eric\Desktop\Documentation\resource.h"
//the following defines are for adding menus without headers or rc files
#define ID_FILE_EXIT 9001
#define ID_STUFF_GO 9002
#define IDC_MAIN_EDIT 101
#define ID_BUTTON 9003
#define ID_EDITCHILD1 100
#define ID_EDITCHILD2 102
#define BUFFER_SIZE 256

using namespace std;

const char g_szClassName[] = "myWindowClass";
BOOL authenticate(char, string);
string bufferToString(char* , int );
BOOL doit = TRUE;
 //Step 4: the Window Procedure

 /*
 Procedure to add items to the main window
 you create the item inside the WM_CREATE function thingy
 look it up online, there are many examples
 This will draw the item in the window, but will not do anything
 next you will need to go to the WM_COMMAND switch statement
 and add a case for the appropriate LWORD of your item

kapish?

 */

LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
    static HWND hwndEDUSER;
    static HWND hwndEDPASS;

    //TCHAR lpszLatin[] =  "Lorem ipsum dolor sit amet, consectetur ";
UpdateWindow(hwnd);
    switch(msg)
    {
        case WM_SIZE:
        {
            HWND hEdit;
            RECT rcClient;

            GetClientRect(hwnd, &rcClient);

            hEdit = GetDlgItem(hwnd, IDC_MAIN_EDIT);
            SetWindowPos(hEdit, NULL, 0, 0, rcClient.right, rcClient.bottom, SWP_NOZORDER);
        }
        break;
        case WM_CREATE:
        {
            HMENU hMenu, hSubMenu;
            HICON hIcon, hIconSm;
            HINSTANCE hInstance;

            if(doit)
                {
            HWND hwndEDUSER = CreateWindowEx(
                                 0,"EDIT",   // predefined class
                                NULL,         // no window title
                                WS_CHILD | WS_VISIBLE |
                                ES_LEFT | ES_MULTILINE ,
                                60, 60, 100, 25,   // set size in WM_SIZE message
                                hwnd,         // parent window
                                (HMENU) ID_EDITCHILD1,   // edit control ID
                                (HINSTANCE) GetWindowLong(hwnd, GWL_HINSTANCE),
                                NULL);        // pointer not needed

            // Add text to the window.
            SendMessage(hwndEDUSER, WM_SETTEXT, 0, (LPARAM)("username"));
            //SendMessage(hwndEdit, EM_SETLIMITTEXT, 3, NULL);

            HWND hwndEDPASS = CreateWindow(
                                 "EDIT",   // predefined class
                                NULL,         // no window title
                                WS_CHILD | WS_VISIBLE |
                                ES_LEFT,
                                60, 90, 100, 25,   // set size in WM_SIZE message
                                hwnd,         // parent window
                                (HMENU) ID_EDITCHILD2,   // edit control ID
                                (HINSTANCE) GetWindowLong(hwnd, GWL_HINSTANCE),
                                NULL);        // pointer not needed

            // Add text to the window.
            SendMessage(hwndEDPASS, WM_SETTEXT, 0, (LPARAM)("password"));
            //SendMessage(hwndEdit, EM_SETLIMITTEXT, 3, NULL);


            HWND hwndButton = CreateWindow(
            "BUTTON",  // Predefined class; Unicode assumed
            "Commit",      // Button text
            WS_TABSTOP | WS_VISIBLE | WS_CHILD | BS_DEFPUSHBUTTON,  // Styles
            200,         // x position
            10,         // y position
            200,        // Button width
            25,        // Button height
            hwnd,     // Parent window
            NULL,       // No menu.
            (HINSTANCE)GetWindowLong(hwnd, GWL_HINSTANCE),
            NULL);      // Pointer not needed.


            HWND boobs = CreateWindow(
            "BUTTON",  // Predefined class; Unicode assumed
            "LOG IN",      // Button text
            WS_TABSTOP | WS_VISIBLE | WS_CHILD | BS_DEFPUSHBUTTON,  // Styles
            200,         // x position
            35,         // y position
            200,        // Button width
            25,        // Button height
            hwnd,     // Parent window
            (HMENU)ID_BUTTON,       // PREVIOUS COMMENT SAID NO MENU, HOWEVER THIS IS WHERE I ADD THE ID FOR THE BUTTON BEING PRESED
            (HINSTANCE)GetWindowLong(hwnd, GWL_HINSTANCE),
            NULL);      // Pointer not needed.
                }

           // HWND hWndExample = CreateWindow("EDIT", "Text Goes Here", WS_VISIBLE | WS_CHILD | ES_CENTER, 10,10,100,100, hwnd, NULL, hInstance, NULL);


            hMenu = CreateMenu();

            hSubMenu = CreatePopupMenu();
            AppendMenu(hSubMenu, MF_STRING, ID_FILE_EXIT, "E&xit");
            AppendMenu(hMenu, MF_STRING | MF_POPUP, (UINT)hSubMenu, "&File");

            hSubMenu = CreatePopupMenu();
            AppendMenu(hSubMenu, MF_STRING, ID_STUFF_GO, "&Go");
            AppendMenu(hMenu, MF_STRING | MF_POPUP, (UINT)hSubMenu, "&Stuff");

            SetMenu(hwnd, hMenu);

            hIcon = static_cast<HICON>(LoadImage(NULL, "C:\menu_one.ico", IMAGE_ICON, 32, 32, LR_LOADFROMFILE));
            if(hIcon)
                SendMessage(hwnd, WM_SETICON, ICON_BIG, (LPARAM)hIcon);
            else
                MessageBox(hwnd, "Could not load large icon!", "Error", MB_OK | MB_ICONERROR);


            hIconSm = static_cast <HICON>(LoadImage(NULL, "C:\menu_two.ico", IMAGE_ICON, 16, 16, LR_LOADFROMFILE));
            if(hIconSm)
                SendMessage(hwnd, WM_SETICON, ICON_SMALL, (LPARAM)hIconSm);
            elsehttp://msdn.microsoft.com/en-us/library/windows/desktop/ms633520(v=VS.85).aspx
                MessageBox(hwnd, "Could not load small icon!", "Error", MB_OK | MB_ICONERROR);

        }
        break;

        /*case WM_LBUTTONDOWN: //mouse click
        case BN_CLICKED:
        {
            char szFileName[MAX_PATH];
            HINSTANCE hInstance = GetModuleHandle(NULL);

            GetModuleFileName(hInstance, szFileName, MAX_PATH);
            MessageBox(hwnd, "The document has been requested, and will be available shortly", "Document Requested", MB_OK | MB_ICONINFORMATION);
        }*/
        break;
        case WM_COMMAND:
            switch(LOWORD(wParam))
            {
                case ID_FILE_EXIT:
                    PostMessage(hwnd, WM_CLOSE, 0, 0);
                break;
                case ID_STUFF_GO:
                    MessageBox(hwnd, "Unavailable", "title", MB_OKCANCEL | MB_ICONINFORMATION );
                break;
                case ID_BUTTON:
                    {

                        //TCHAR user[BUFFER_SIZE];
                        //string user ="";
                        //static char user[256];
                        //char id[256];
                        //((WORD*)user)[0] = BUFFER_SIZE; //cast variable user of type TCHAR into WORD. Set position 0 of said WORD variable to BUFFER_SIZE (needed by EM_GETLINE)
                       // SendMessage(hwndEDUSER, EM_GETLINE, 0, (LPARAM)user);

                        // Edit_GetText(hwndEDUSER,(LPTSTR) user,BUFFER_SIZE);

                        //GetWindowText(hwndEDUSER, (LPSTR)user, 256);
                        //GetDlgItemText(hwndEDUSER, ID_EDITCHILD1, (LPTSTR)user,BUFFER_SIZE);
                        //const char id= *user;

                        int len = SendMessage(hwndEDUSER, WM_GETTEXTLENGTH, 0, 0);
                        char* buffer = new char[len];
                        UpdateWindow(hwnd);
                        SendMessage(hwndEDUSER, WM_GETTEXT, 0, (LPARAM)buffer);
                        //return buffer;
                        string user(buffer);
                        fstream users;
                        users.open("C:\\users\\Eric\\Desktop\\Documentation\\user1.txt");
                        users << user;
                        users.close();
                        doit = FALSE;
                        //PostMessage(hwnd, WM_PAINT, 0, 0);
                        UpdateWindow(hwnd);
                        //char id = (char)user;
                       /* Edit_GetText(hwndEDUSER, (LPTSTR)eyeD,50);
                       string id(eyeD);
                        if(id=="2"){MessageBox(hwnd, "BITTCH", "Document Requested", MB_OK | MB_ICONINFORMATION);} */

                        //string id = (string)user;
                       // authenticate(id, "");
                        //char szFileName[MAX_PATH];
                        //HINSTANCE hInstance = GetModuleHandle(NULL);

                        //GetModuleFileName(hInstance, szFileName, MAX_PATH);
                        MessageBox(hwnd,buffer, "Title", MB_OK | MB_ICONINFORMATION);
                    }
                break;
              /*  case BN_CLICKED:
                    {
                    char szFileName[MAX_PATH];
                    HINSTANCE hInstance = GetModuleHandle(NULL);

                    GetModuleFileName(hInstance, szFileName, MAX_PATH);
                    MessageBox(hwnd, "Commit", "Document Requested", MB_OK | MB_ICONINFORMATION);
                    }
                break;*/
            }
        break;
        case WM_CLOSE:
            DestroyWindow(hwnd);
        break;
        case WM_DESTROY:
            PostQuitMessage(0);
        break;
        /*case WM_PAINT:
        {
            PAINTSTRUCT ps;
            HDC hdc = BeginPaint(hwnd, &ps);

            // All painting occurs here, between BeginPaint and EndPaint.

            FillRect(hdc, &ps.rcPaint, (HBRUSH) (COLOR_WINDOW+1));

            EndPaint(hwnd, &ps);
        }*/
        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;
    //Step 1: Registering the Window Class;

    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); //comment this out for header and rc
    wc.hCursor       = LoadCursor(NULL, IDC_ARROW);
    wc.hbrBackground = (HBRUSH)(COLOR_INACTIVEBORDER);//(HBRUSH)(COLOR_WINDOW+1);
    wc.lpszMenuName  = NULL;
    wc.lpszClassName = g_szClassName;
    wc.hIconSm       = LoadIcon(NULL, IDI_APPLICATION); //comment this out for header and rc
    //wc.lpszMenuName  = MAKEINTRESOURCE(IDR_MYMENU); //comment this out for header and rc
    //wc.hIcon  = LoadIcon(GetModuleHandle(NULL), MAKEINTRESOURCE(IDI_MYICON));
    //wc.hIconSm  = (HICON)LoadImage(GetModuleHandle(NULL), MAKEINTRESOURCE(IDI_MYICON), IMAGE_ICON, 16, 16, 0);

    if(!RegisterClassEx(&wc))
    {
        MessageBox(NULL, "Window Registration Failed!", "Error!",
            MB_ICONEXCLAMATION | MB_OK);
        return 0;
    }
    // Step 2: Creating the Window
    hwnd = CreateWindowEx(
        WS_EX_CLIENTEDGE,
        g_szClassName,
        "nameofwin",
        WS_OVERLAPPEDWINDOW,
        CW_USEDEFAULT, CW_USEDEFAULT, 600, 480,
        NULL, NULL, hInstance, NULL);
    if(hwnd == NULL)
    {
        MessageBox(NULL, "Window Creation Failed!", "Error!",
            MB_ICONEXCLAMATION | MB_OK);
        return 0;
    }
    ShowWindow(hwnd, nCmdShow);
    UpdateWindow(hwnd);
    // Step 3: The Message Loop
    while(GetMessage(&Msg, NULL, 0, 0) > 0) //this piece of code is responsible for collecting events (clicks.. etc) and reporting them to the window
    {
        TranslateMessage(&Msg);
        DispatchMessage(&Msg);
    }
    return Msg.wParam;
}

BOOL authenticate(char uid, string pwd)
{
    //string boobs=uid;
    fstream users;
    users.open("C:\\users\\Eric\\Desktop\\Documentation\\user1.txt");
    users << uid;
    users.close();
    return TRUE;
}

Answer 1

您正在为句柄声明一个静态变量，HWND hwndEDUSER。但是在创建窗口时，您没有使用该变量。您正在声明一个新的，它超出了范围并且丢失了。稍后，您使用静态变量...其中没有任何内容。