albumdb.cpp

《Windows CE 6.0开发者参考》（《Programming Windows Embedded CE 6.0 Developer Reference》）第四版书中的源代码

            break;

        // Double click indicates edit
        case NM_DBLCLK:
            PostMessage (hWnd, WM_COMMAND, MAKELPARAM (IDM_EDIT, 0), 0);
            break;

        // Ignore cache hinting for db example.
        case LVN_ODCACHEHINT:
            break;

        case LVN_ODFINDITEM:
            // We should do a reverse lookup here to see if
            // an item exists for the text passed.
            return -1;
        }
    }
    return 0;
}
//----------------------------------------------------------------------
// DoDestroyMain - Process WM_DESTROY message for window.
//
LRESULT DoDestroyMain (HWND hWnd, UINT wMsg, WPARAM wParam, 
                       LPARAM lParam) {
    PostQuitMessage (0);
    return 0;
}
//======================================================================
// Command handler routines
//----------------------------------------------------------------------
// DoMainCommandDelDB - Process Program Delete command.
//
LPARAM DoMainCommandDelDB (HWND hWnd, WORD idItem, HWND hwndCtl, 
                           WORD wNotifyCode) {
    int i, rc;

    i = MessageBox (hWnd, TEXT ("Delete the entire database?"), 
                    TEXT ("Delete"), MB_YESNO);
    if (i != IDYES) 
        return 0;
    if (g_oidDB) {
        CloseHandle (g_hDB);
        rc = CeDeleteDatabase (g_oidDB);
        if (rc == 0) {
            ErrBox (hWnd, TEXT ("Couldn\'t delete database. rc=%d"), 
                    GetLastError());
            g_hDB = OpenDB (hWnd, NULL);   // Open the database.
            return 0;
        }
        g_hDB = INVALID_HANDLE_VALUE;
        g_oidDB = 0;
    }
    ListView_SetItemCount (GetDlgItem (hWnd, ID_LISTV), 0);
    return 0;
}
//----------------------------------------------------------------------
// DoMainCommandExit - Process Program Exit command.
//
LPARAM DoMainCommandExit (HWND hWnd, WORD idItem, HWND hwndCtl, 
                          WORD wNotifyCode) {
    SendMessage (hWnd, WM_CLOSE, 0, 0);
    return 0;
}
//----------------------------------------------------------------------
// DoMainCommandNew - Process Program New command.
//
LPARAM DoMainCommandNew (HWND hWnd, WORD idItem, HWND hwndCtl, 
                         WORD wNotifyCode) {
    PCEPROPVAL pcepv;
    int i, rc;
    CEOID oid;
    HWND hwndLV = GetDlgItem (hWnd, ID_LISTV);
    // Display the new/edit dialog.
    pcepv = 0;
    rc = DialogBoxParam (hInst, TEXT ("EditAlbumDlg"), hWnd, 
                         EditAlbumDlgProc, (LPARAM)&pcepv);
    if (rc == 0) 
        return 0;

    // Write the record.
    oid = CeWriteRecordProps(g_hDB, 0, NUM_DB_PROPS, pcepv);
    if (!oid) 
        ErrBox (hWnd, TEXT ("Write Rec fail. rc=%d"), GetLastError());
    
    ClearCache ();                              // Clear the lv cache.
    i = ListView_GetItemCount (hwndLV) + 1;     // Increment list view
                                                // count.
    ListView_SetItemCount (hwndLV, i);
    InvalidateRect (hwndLV, NULL, TRUE);        // Force redraw.
    return 0;
}
//----------------------------------------------------------------------
// DoMainCommandEdit - Process Program Edit command.
//
LPARAM DoMainCommandEdit (HWND hWnd, WORD idItem, HWND hwndCtl, 
                          WORD wNotifyCode) {
    PCEPROPVAL pcepv = 0;
    int nSel, rc;
    WORD wProps = 0;
    DWORD dwRecSize, dwIndex;
    CEOID oid;
    HWND hwndLV = GetDlgItem (hWnd, ID_LISTV);

    nSel = ListView_GetSelectionMark (hwndLV);
    if (nSel == -1) 
        return 0;

    // Seek to the necessary record.
    oid = CeSeekDatabase (g_hDB, CEDB_SEEK_BEGINNING, nSel, &dwIndex);
    if (oid == 0) {
        ErrBox (hWnd, TEXT ("Db item not found. rc=%d"), GetLastError());
        return 0;
    }
    // Read all properties for the record. Have the system
    // allocate the buffer containing the data.
    oid = CeReadRecordPropsEx (g_hDB, CEDB_ALLOWREALLOC, &wProps, NULL,
                               (LPBYTE *)&pcepv, &dwRecSize, 0);
    if (oid == 0) {
        ErrBox (hWnd, TEXT ("Db item not read. rc=%d"), GetLastError());
        return 0;
    }
    // Display the edit dialog.
    rc = DialogBoxParam (hInst, TEXT ("EditAlbumDlg"), hWnd, 
                         EditAlbumDlgProc, (LPARAM)&pcepv);
    if (rc == 0) 
        return 0;

    // Write the record.
    oid = CeWriteRecordProps(g_hDB, oid, NUM_DB_PROPS, pcepv);
    if (!oid) 
        ErrBox (hWnd, TEXT ("Write Rec fail. rc=%d"), GetLastError());

    LocalFree ((LPBYTE)pcepv);
    ClearCache ();                              // Clear the lv cache.

    InvalidateRect (hwndLV, NULL, TRUE);        // Force redraw.
    return 0;
}
//----------------------------------------------------------------------
// DoMainCommandDelete - Process Program Delete command.
//
LPARAM DoMainCommandDelete (HWND hWnd, WORD idItem, HWND hwndCtl, 
                            WORD wNotifyCode) {
    HWND hwndLV;
    TCHAR szText[64];
    DWORD dwIndex;
    int i, nSel;
    CEOID oid;

    hwndLV = GetDlgItem (hWnd, ID_LISTV);
    nSel = ListView_GetSelectionMark (hwndLV);
    if (nSel != -1) {

        wsprintf (szText, TEXT ("Delete this item?")); 
        i = MessageBox (hWnd, szText, TEXT ("Delete"), MB_YESNO);
        if (i != IDYES) 
            return 0;

        // Seek to the necessary record.
        oid = CeSeekDatabase (g_hDB, CEDB_SEEK_BEGINNING, nSel, &dwIndex);
        CeDeleteRecord (g_hDB, oid);

        // Reduce the list view count by one and force redraw.
        i = ListView_GetItemCount (hwndLV) - 1;
        ListView_SetItemCount (hwndLV, i);
        ClearCache ();                          // Clear the lv cache.
        InvalidateRect (hwndLV, NULL, TRUE);
    }
    return 0;
}
//----------------------------------------------------------------------
// DoMainCommandSort - Process the Sort commands.
//
LPARAM DoMainCommandSort(HWND hWnd, WORD idItem, HWND hwndCtl, 
                         WORD wNotifyCode) {
    int nSort;

    switch (idItem) {
    case IDM_SORTNAME:
        nSort = 0;
        break;
    case IDM_SORTARTIST:
        nSort = 1;
        break;
    case IDM_SORTCATEGORY:
        nSort = 2;
        break;
    }
    if (nSort == g_nLastSort)
        return 0;

    ReopenDatabase (hWnd, nSort);      // Close and reopen the database.
    return 0;
}
//----------------------------------------------------------------------
// DoMainCommandAbout - Process the Help | About menu command.
//
LPARAM DoMainCommandAbout(HWND hWnd, WORD idItem, HWND hwndCtl, 
                          WORD wNotifyCode) {
    // Use DialogBox to create modal dialog.
    DialogBox (hInst, TEXT ("aboutbox"), hWnd, AboutDlgProc);
    return 0;
}
//----------------------------------------------------------------------
// CreateLV - Creates the list view control
//
HWND CreateLV (HWND hWnd, RECT *prect) {
    HWND hwndLV;
    LVCOLUMN lvc;

    // Create album list window.  
    hwndLV = CreateWindowEx (0, WC_LISTVIEW, TEXT (""), 
                         WS_VISIBLE | WS_CHILD | WS_VSCROLL |
                         LVS_OWNERDATA | WS_BORDER | LVS_REPORT, 
                         prect->left, prect->top,
                         prect->right - prect->left,
                         prect->bottom - prect->top,
                         hWnd, (HMENU)ID_LISTV, 
                         hInst, NULL);

    // Add columns.
    if (hwndLV) {
        lvc.mask = LVCF_TEXT | LVCF_WIDTH | LVCF_FMT | LVCF_SUBITEM;
        lvc.fmt = LVCFMT_LEFT;
        lvc.cx = 150;
        lvc.pszText = TEXT ("Name");
        lvc.iSubItem = 0;
        SendMessage (hwndLV, LVM_INSERTCOLUMN, 0, (LPARAM)&lvc);

        lvc.mask |= LVCF_SUBITEM;
        lvc.pszText = TEXT ("Artist");
        lvc.cx = 100;
        lvc.iSubItem = 1;
        SendMessage (hwndLV, LVM_INSERTCOLUMN, 1, (LPARAM)&lvc);

        lvc.mask |= LVCF_SUBITEM;
        lvc.pszText = TEXT ("Category");
        lvc.cx = 100;
        lvc.iSubItem = 2;
        SendMessage (hwndLV, LVM_INSERTCOLUMN, 2, (LPARAM)&lvc);
    }
    return hwndLV;
}
//----------------------------------------------------------------------
// OpenDB - Open database.
//
HANDLE OpenDB (HWND hWnd, LPTSTR lpszName) {
    // Reinitialize the notify request structure.
    cenr.dwSize = sizeof (cenr);
    cenr.hwnd = hWnd;
    cenr.dwFlags = CEDB_EXNOTIFICATION;

    if (lpszName)
        g_oidDB = 0;
    return CeOpenDatabaseEx2 (&g_guidDB, &g_oidDB, lpszName, 
                              &g_diex.rgSortSpecs[g_nLastSort], 
                              0, &cenr);
}
//----------------------------------------------------------------------
// OpenCreateDB - Open database, create if necessary.
//
HANDLE OpenCreateDB (HWND hWnd, int *pnRecords) {
    int rc;
    CEOIDINFO oidinfo;

    g_oidDB = 0;
    g_hDB = OpenDB (hWnd, TEXT ("\\Albums"));
    if (g_hDB == INVALID_HANDLE_VALUE) {
        rc = GetLastError();
        if (rc == ERROR_FILE_NOT_FOUND) {

            g_oidDB = CeCreateDatabaseEx2 (&g_guidDB, &g_diex);
            if (g_oidDB == 0) {
                ErrBox (hWnd, TEXT ("Database create failed. rc=%d"), 
                        GetLastError());
                return 0;
            }
            g_hDB = OpenDB (hWnd, NULL);
        }
    } 
    if (CeOidGetInfo (g_oidDB, &oidinfo))
		*pnRecords = oidinfo.infDatabase.wNumRecords;
	else
		*pnRecords = 0;
    return g_hDB;
}
//----------------------------------------------------------------------
// ClearCache - Clears the one-item cache for the list view control
//
void ClearCache (void) {

    if (g_pLastRecord)
        LocalFree (g_pLastRecord);
    g_pLastRecord = 0;            
    g_nLastItem = -1;
    return;
}
//----------------------------------------------------------------------
// ReopenDatabase - Closes and reopens the database 
//
void ReopenDatabase (HWND hWnd, int nNewSort) {
    int nCnt; 

    if (nNewSort != -1)
        g_nLastSort = nNewSort;

    if (g_hDB)
        CloseHandle (g_hDB);
    ClearCache ();                        // Clear the lv cache.

    g_hDB = OpenCreateDB (hWnd, &nCnt);

    ListView_SetItemCount (GetDlgItem (hWnd, ID_LISTV), nCnt);
    InvalidateRect (GetDlgItem (hWnd, ID_LISTV), NULL, 0);
    return;
}
//----------------------------------------------------------------------
// Get the album data from the database for the requested lv item.
//
int GetItemData (int nItem, PLVCACHEDATA pcd) {
    static WORD wProps;
    DWORD dwIndex;
    CEOID oid;
    PCEPROPVAL pRecord = NULL;
    DWORD dwRecSize;
    int i;

    // See if the item requested was the previous one. If so,
    // just use the old data.
    if ((nItem == g_nLastItem) && (g_pLastRecord)) 
        pRecord = (PCEPROPVAL)g_pLastRecord;
    else {
        // Seek to the necessary record.
        oid = CeSeekDatabase (g_hDB, CEDB_SEEK_BEGINNING, nItem, &dwIndex);
        if (oid == 0) {
            ErrBox (NULL, TEXT ("Db item not found. rc=%d"), 
                    GetLastError());
            return 0;
        }
        // Read all properties for the record.  Have the system
        // allocate the buffer containing the data.
        oid = CeReadRecordProps (g_hDB, CEDB_ALLOWREALLOC, &wProps, NULL,
                                 (LPBYTE *)&pRecord, &dwRecSize);
        if (oid == 0) {
            ErrBox (NULL, TEXT ("Db item not read. rc=%d"), 
                    GetLastError());
            return 0;
        }
        // Free old record, and save the newly read one.
        if (g_pLastRecord)
            LocalFree (g_pLastRecord);
        g_nLastItem = nItem;
        g_pLastRecord = (LPBYTE)pRecord;

    }
    // Copy the data from the record to the album structure.
    for (i = 0; i < wProps; i++) {
        switch (pRecord->propid) {
        case PID_NAME:
            StringCchCopy (pcd->Album.szName, 
			               dim (pcd->Album.szName),
			               pRecord->val.lpwstr);
            break;
        case PID_ARTIST:
            StringCchCopy (pcd->Album.szArtist, 
			               dim (pcd->Album.szArtist),
			               pRecord->val.lpwstr);
            break;
        case PID_CATEGORY:
            pcd->Album.sCategory = pRecord->val.iVal;
            break;
        case PID_NUMTRACKS:
            pcd->Album.sNumTracks = pRecord->val.iVal;
            break;
        }
        pRecord++;
    }
    return 1;