我的第一个用EVC写的程序!
// EvcSymbolTest.cpp : Defines the entry point for the application.
//

#include "stdafx.h"
#include "resource.h"
#include <windows.h>
#include <windowsx.h>
#include <ScanCAPI.h>
#include <stdio.h>
#include <string.h>
#include <wchar.h>
#define     countof(x) sizeof(x)/sizeof(x[0])

BOOL CALLBACK MAINProc(HWND,UINT,WPARAM,LPARAM);
LRESULT CALLBACK EditProc(HWND,UINT,WPARAM,LPARAM);
BOOL Save(HWND hwnd_barcode,HWND hwnd_qty);
void InitFormControl(HWND);
WNDPROC PreEditProc[2];

HINSTANCE hInst    = NULL;
HANDLE            hScanner                = NULL;
LPSCAN_BUFFER    lpScanBuffer            = NULL;
TCHAR            szScannerName[MAX_PATH] = TEXT("SCN1:");    // default scanner name
DWORD            dwScanSize                = 7095;                // default scan buffer size    
DWORD            dwScanTimeout            = 0;                // default timeout value (0 means no timeout)    
BOOL            bUseText                = TRUE;
BOOL            bTriggerFlag            = FALSE;
BOOL            bRequestPending            = FALSE;
BOOL            bStopScanning            = FALSE;

enum tagUSERMSGS
{
    UM_SCAN    = WM_USER + 0x200,
    UM_STARTSCANNING,
    UM_STOPSCANNING
};

int WINAPI WinMain(    HINSTANCE hInstance,
                    HINSTANCE hPrevInstance,
                    LPTSTR    lpCmdLine,
                    int       nCmdShow)
{
    int nResult;

    hInst = hInstance;
    nResult = DialogBoxParamW(hInstance, MAKEINTRESOURCE(IDD_MAIN), NULL, MAINProc,0L);

    return nResult;
}

BOOL CALLBACK MAINProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
    DWORD dwResult;
    LPSCAN_BUFFER    lpScanBuf;
    static HWND    hctl_temp,hctl_barcode, hctl_qty, hctl_status,hctl_info;
    switch(uMsg)
    {
    case WM_INITDIALOG:
        PostMessage(hwnd,UM_STARTSCANNING,0,0L);
        hctl_barcode=GetDlgItem(hwnd,IDC_EDIT_Barcode);
        hctl_qty=GetDlgItem(hwnd,IDC_EDIT_Qty);
        hctl_status=GetDlgItem(hwnd,IDC_STATIC_STATUS);
        hctl_info=GetDlgItem(hwnd,IDC_STATIC_INFO);
        InitFormControl(hwnd);
        //子类化
        PreEditProc[0]=(WNDPROC) SetWindowLong (hctl_barcode, 
                                             GWL_WNDPROC, (LONG) EditProc) ;
        PreEditProc[1]=(WNDPROC) SetWindowLong (hctl_qty, 
                                     GWL_WNDPROC, (LONG) EditProc) ;
        break;
    case UM_STARTSCANNING:
        dwResult=SCAN_Open(szScannerName,&hScanner);
        if(dwResult!=E_SCN_SUCCESS)
        {
            MessageBox(hwnd,TEXT("不能打开激光器"),TEXT("提示"),MB_OK);
            SendMessage(hwnd,UM_STOPSCANNING,0,0L);
            break;
        }
        dwResult=SCAN_Enable(hScanner);
        
        if(dwResult!=E_SCN_SUCCESS)
        {
            MessageBox(hwnd,TEXT("激光器不可用"),TEXT("提示"),MB_OK);
            SendMessage(hwnd,UM_STOPSCANNING,0,0L);
            break;
        }
        lpScanBuffer = SCAN_AllocateBuffer(bUseText, dwScanSize);
        if (lpScanBuffer==NULL)
        {
            MessageBox(hwnd,TEXT("未能分配扫描缓冲"),TEXT("提示"),MB_OK);
            SendMessage(hwnd,UM_STOPSCANNING,0,0L);
            return TRUE;
        }
        //SCAN_ReadLabelMsg扫描成功后向hwnd发送UM_SCAN的消息
        dwResult=SCAN_ReadLabelMsg(hScanner,
            lpScanBuffer,
            hwnd,
            UM_SCAN,
            dwScanTimeout,
            NULL);
        if(dwResult!=E_SCN_SUCCESS)
        {
            MessageBox(hwnd,TEXT("SCAN_ReadLabelMsg发生错误"),TEXT("提示"),MB_OK);
            SendMessage(hwnd,UM_STOPSCANNING,0,0L);
        }
        else
        {
            //只有到最后成功得到缓存后才置此标志为TRUE
            bRequestPending=TRUE;
        }
        break;
        return true;
    case UM_STOPSCANNING:
        //在未停止扫描且未已正常得到缓存后才执行SCAN_Flush
        if (!bStopScanning && bRequestPending)    
        {
            SCAN_Flush(hScanner);
        }

        if (!bRequestPending)            
        {                             
            SCAN_Disable(hScanner);

            if (lpScanBuffer)
                SCAN_DeallocateBuffer(lpScanBuffer);

            SCAN_Close(hScanner);

            EndDialog(hwnd, 0);
        }
        bStopScanning = TRUE;
        break;
    case WM_ACTIVATE:
        switch(LOWORD(wParam))
        {
        case WA_INACTIVE:

            if (bRequestPending)
            {
                dwResult=SCAN_Flush(hScanner);
            }
            break;
        default:
            if (!bRequestPending && lpScanBuffer != NULL && !bStopScanning)
            {
                dwResult=SCAN_ReadLabelMsg(hScanner,
                    lpScanBuffer,
                    hwnd,
                    UM_SCAN,
                    dwScanTimeout,
                    NULL);
                if (dwResult!=E_SCN_SUCCESS)
                {
                    MessageBox(hwnd,TEXT("SCAN_ReadLabelMsg发生错误"),TEXT("提示"),MB_OK);
                    SendMessage(hwnd,UM_STOPSCANNING,0,0L);
                }
            }
            break;
        }
        break;
    case UM_SCAN:
        bRequestPending=FALSE;
        lpScanBuf=(LPSCAN_BUFFER)lParam;
        if(lpScanBuf==NULL)
        {
            MessageBox(hwnd,TEXT("未能正确得到数据"),TEXT("提示"),MB_OK);
            SendMessage(hwnd,UM_STOPSCANNING,0,0L);
        }
        switch(SCNBUF_GETSTAT(lpScanBuf))
        {
        case E_SCN_SUCCESS:
            hctl_temp=GetFocus();
            if(hctl_temp==hctl_barcode ||hctl_temp==hctl_qty)
            {
                Edit_SetText(hctl_temp,(LPTSTR)SCNBUF_GETDATA(lpScanBuffer));
            }
            else
            {
                Edit_SetText(hctl_barcode,(LPTSTR)SCNBUF_GETDATA(lpScanBuffer));
                SendMessage(hwnd,WM_KEYDOWN,VK_RETURN,NULL);
            }
            break;
        }
        if (GetFocus())
        {
            dwResult = SCAN_ReadLabelMsg(hScanner,
                                         lpScanBuffer,
                                         hwnd,
                                         uMsg,
                                         dwScanTimeout,
                                         NULL);
            if ( dwResult != E_SCN_SUCCESS )
            {
                MessageBox(hwnd,TEXT("SCAN_ReadLabelMsg未能正确得到数据"),TEXT("提示"),MB_OK);
                SendMessage(hwnd,UM_STOPSCANNING,0,0L);
            }
            else
                bRequestPending = TRUE;
        }
        return TRUE;
    case WM_COMMAND:
        switch (LOWORD(wParam))
        {
        case IDCANCEL:
            bRequestPending=TRUE;
            SendMessage(hwnd,UM_STOPSCANNING,0,0L);
            bRequestPending=FALSE;
            SendMessage(hwnd,UM_STOPSCANNING,0,0L);
            break;
        }
        return TRUE;
    case WM_KEYDOWN:
        switch (wParam)
        {
        case VK_RETURN:
            hctl_temp=GetFocus();
            if (hctl_temp==hctl_barcode)
            {
                SetFocus(hctl_qty);
                SendMessage(hctl_qty,EM_SETSEL,0,-1);
            }
            else if (hctl_temp==hctl_qty)
            {
                if (Save(hctl_barcode,hctl_qty)==TRUE)
                {
                    SetWindowText(hctl_info,TEXT("追加数据成功!"));
                    InitFormControl(hwnd);
                }
                else
                {
                    SetWindowText(hctl_info,TEXT("追加数据失败!"));
                }
            }
            else
            {
                SetFocus(hctl_barcode);
            }
            break;
        case VK_F1:
            InitFormControl(hwnd);
            break;
        case VK_F2:
            hctl_temp=GetFocus();
            if (hctl_temp==hctl_qty)
            {
                Edit_SetText(hctl_temp,TEXT("-"));
                Edit_SetSel(hctl_temp,1,1);
            }
            break;
        case VK_F3:
            break;
        }
        break;
    }

    return FALSE;
}

//初始化
void InitFormControl(HWND hwnd)
{
    HWND hctl_barcode, hctl_qty;
    hctl_barcode=GetDlgItem(hwnd,IDC_EDIT_Barcode);
    Edit_SetText(hctl_barcode,TEXT(""));
    hctl_qty=GetDlgItem(hwnd,IDC_EDIT_Qty);
    Edit_SetText(hctl_qty,TEXT("1"));
    SetFocus(hctl_barcode);
}

//子类化文本框
LRESULT CALLBACK EditProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
     int id = GetWindowLong (hwnd, GWL_ID) ;
     LPMSG msg;
     WNDPROC proc;
     switch (uMsg)
     {
     case WM_GETDLGCODE :
        msg=(LPMSG) lParam;
        switch(msg->message)
        {
        case WM_KEYDOWN:
            switch(msg->wParam)
            {
            case VK_TAB:
            case VK_RETURN:
            case VK_F1:
            case VK_F2:
            case VK_F3:
                SendMessage(GetParent(hwnd),msg->message,msg->wParam,msg->lParam);
                break;
            }
        }
        /*
        switch(msg->message)
        {
        case EN_SETFOCUS:
            hctl_qty=GetDlgItem(GetParent(hwnd),IDC_EDIT_Qty);
            if (msg->hwnd==hctl_qty)
            {
                SetDlgItemInt(GetParent(hwnd),IDC_STATIC_STATUS,msg->message,FALSE);
                //Edit_SetSel(hwnd,-1,GetWindowTextLength(hwnd));
                Edit_SetSel(hwnd,0,-1);
                //SNDMSG(hwnd, EM_SETSEL, 0, GetWindowTextLength(hwnd));
            }
        }
        */
     }
     if (id==IDC_EDIT_Barcode)
     {
         proc=PreEditProc[0];
     }
     else if (id==IDC_EDIT_Qty)
     {
        proc=PreEditProc[1];
     }
     return CallWindowProc (proc, hwnd, uMsg, wParam, lParam) ;
}

//保存
BOOL Save(HWND hwnd_barcode,HWND hwnd_qty)
{
    int result=FALSE;
    FILE * file_handling=NULL;
    TCHAR barcode[255],qty[255];
    TCHAR buffer[255];
    char ansiBuffer[255];
    GetWindowText(hwnd_barcode,buffer,sizeof(buffer));
    if (!lstrlen (buffer))
    {
        MessageBox(NULL,TEXT("请扫描或输入条码!"),TEXT("提示"),MB_OK);
        SetFocus(hwnd_barcode);
        return result;
    }
    else
    {
        lstrcpy (barcode,buffer);
    }
    memset(buffer,0,sizeof(buffer));
    GetWindowText(hwnd_qty,buffer,sizeof(buffer));
    if (!lstrlen (buffer))
    {
        MessageBox(NULL,TEXT("请输入数量!"),TEXT("提示"),MB_OK);
        SetFocus(hwnd_qty);
        return result;
    }
    else                    //判断数字
    {
        
    }
    lstrcpy (qty,buffer);
    memset(buffer,0,sizeof(buffer));
    swprintf(buffer,TEXT("%s,%s\n"),barcode,qty);
    if (file_handling=fopen(