使用VC++ 的OLE DB技术连接SQLCE数据库的开发环境搭建过程，以及所有的代码

以下是使用VC++的OLE DB技术连接SQLCE数据库的开发环境搭建过程和代码：

1. 首先需要下载并安装SQL Server Compact Edition (SQLCE) 3.5 SP2 版本，可以从微软官网下载。

2. 打开Visual Studio，创建一个新的VC++项目。在项目属性中，选择“常规”选项卡，将“字符集”设置为“使用多字节字符集”。

3. 在项目中添加对oledb.h和sqloledb.h的引用。通过右键单击项目，并选择“属性”选项，然后在“C/C++”选项卡下的“常规”中添加包含目录。在“链接器”选项卡下的“输入”中添加附加依赖项“oledb.lib”和“sqloledb.lib”。

4. 在代码中添加以下头文件：

#include <oledb.h>
#include <sqloledb.h>

5. 创建一个OLE DB连接对象和一个命令对象：

IDBInitialize *pIDBInitialize = NULL;
IDBCreateSession *pIDBCreateSession = NULL;
IDBCreateCommand *pIDBCreateCommand = NULL;
ICommandText *pICommandText = NULL;

6. 初始化OLE DB连接：

CoInitialize(NULL);
hr = CoCreateInstance(CLSID_SQLSERVERCE, NULL, CLSCTX_INPROC_SERVER, IID_IDBInitialize, (void **)&pIDBInitialize);
hr = pIDBInitialize->Initialize();

7. 创建一个OLE DB会话对象：

hr = pIDBInitialize->QueryInterface(IID_IDBCreateSession, (void **)&pIDBCreateSession);
hr = pIDBCreateSession->CreateSession(NULL, IID_IUnknown, (void **)&pSession);

8. 创建一个命令对象：

hr = pSession->QueryInterface(IID_IDBCreateCommand, (void **)&pIDBCreateCommand);
hr = pIDBCreateCommand->CreateCommand(NULL, IID_IUnknown, (void **)&pCommand);
hr = pCommand->QueryInterface(IID_ICommandText, (void **)&pICommandText);

9. 执行SQL查询语句：

hr = pICommandText->SetCommandText(DBGUID_DBSQL, L"SELECT * FROM [TableName]");
hr = pCommand->Execute(NULL, IID_IRowset, NULL, NULL, (IUnknown **)&pIRowset);

完整的代码示例可参考以下代码：

#include <windows.h>
#include <oledb.h>
#include <sqloledb.h>
#include <stdio.h>

int main()
{
    HRESULT hr;

    // 创建OLE DB连接对象和命令对象
    IDBInitialize *pIDBInitialize = NULL;
    IDBCreateSession *pIDBCreateSession = NULL;
    IDBCreateCommand *pIDBCreateCommand = NULL;
    ICommandText *pICommandText = NULL;
    IRowset *pIRowset = NULL;

    // 初始化OLE DB连接
    CoInitialize(NULL);
    hr = CoCreateInstance(CLSID_SQLSERVERCE, NULL, CLSCTX_INPROC_SERVER, IID_IDBInitialize, (void **)&pIDBInitialize);
    hr = pIDBInitialize->Initialize();

    // 创建OLE DB会话
    IUnknown *pSession = NULL;
    hr = pIDBInitialize->QueryInterface(IID_IDBCreateSession, (void **)&pIDBCreateSession);
    hr = pIDBCreateSession->CreateSession(NULL, IID_IUnknown, (void **)&pSession);

    // 创建命令对象
    ICommand *pCommand = NULL;
    hr = pSession->QueryInterface(IID_IDBCreateCommand, (void **)&pIDBCreateCommand);
    hr = pIDBCreateCommand->CreateCommand(NULL, IID_IUnknown, (void **)&pCommand);
    hr = pCommand->QueryInterface(IID_ICommandText, (void **)&pICommandText);

    // 执行SQL查询语句
    hr = pICommandText->SetCommandText(DBGUID_DBSQL, L"SELECT * FROM [TableName]");
    hr = pCommand->Execute(NULL, IID_IRowset, NULL, NULL, (IUnknown **)&pIRowset);

    // 处理查询结果
    DBCOUNTITEM cRowsObtained;
    HROW rghRows[10];
    while (TRUE)
    {
        hr = pIRowset->GetNextRows(NULL, 0, 10, &cRowsObtained, &rghRows);
        if (hr == DB_S_ENDOFROWSET)
            break;

        for (int i = 0; i < cRowsObtained; i++)
        {
            printf("Row %d: ", i);

            // 获取每个列的值
            DBBINDING dbBinding;
            dbBinding.iOrdinal = 1;
            dbBinding.wType = DBTYPE_WSTR;
            dbBinding.obValue = 0;
            dbBinding.cbMaxLen = 256;
            dbBinding.obLength = dbBinding.cbMaxLen;
            dbBinding.dwPart = DBPART_VALUE | DBPART_LENGTH | DBPART_STATUS;
            dbBinding.pTypeInfo = NULL;
            dbBinding.pObject = NULL;
            dbBinding.pBindExt = NULL;
            dbBinding.dwFlags = 0;

            DBCOLUMNINFO dbColumnInfo;
            dbColumnInfo.pwszName = L"ColumnName";
            dbColumnInfo.dwType = DBTYPE_WSTR;
            dbColumnInfo.ulColumnSize = 256;
            dbColumnInfo.dwFlags = 0;
            dbColumnInfo.lcid = NULL;
            dbColumnInfo.pTypeInfo = NULL;
            dbColumnInfo.cbMaxLen = 0;
            dbColumnInfo.dwPart = DBPART_VALUE | DBPART_LENGTH | DBPART_STATUS;
            dbColumnInfo.pwcsName = NULL;

            HACCESSOR hAccessor;
            hr = pIRowset->QueryInterface(IID_IAccessor, (void **)&pAccessor);
            hr = pAccessor->CreateAccessor(DBACCESSOR_ROWDATA, 1, &dbBinding, sizeof(dbColumnInfo), &hAccessor, NULL);
            WCHAR wszValue[256];
            DWORD dwLength;
            hr = pAccessor->GetData(rghRows[i], hAccessor, wszValue, &dwLength);
            wprintf(L"%s\n", wszValue);

            hr = pAccessor->ReleaseAccessor(hAccessor, NULL);
            hr = pAccessor->Release();
        }

        hr = pIRowset->ReleaseRows(cRowsObtained, rghRows, NULL, NULL, NULL);
    }

    // 释放资源
    hr = pICommandText->Release();
    hr = pCommand->Release();
    hr = pSession->Release();
    hr = pIDBCreateSession->Release();
    hr = pIDBCreateCommand->Release();
    hr = pIDBInitialize->Release();

    CoUninitialize();

    return 0;
}

希望以上内容能对您有所帮助。