枚舉注冊表DSN，實現用ADO動態選擇數據源

用ADO通過DSN動態連接數據庫時:(MFC基於對話框 )

//stdafx.h
#import "c:\program files\common files\system\ado\msado15.dll" no_namespace rename("EOF","adoEOF") 
//主程序初始化函數
BOOL CADO2App::InitInstance()
{
    AfxEnableControlContainer();

    AfxOleInit();//初始化COM庫

首先添加一個對話框，然後調用該對話框初始化的時候讀取DSN名字

//把DSN名字顯示到列表框中    列表框ID :IDC_DSN_LIST
((CListBox*)GetDlgItem(IDC_DSN_LIST))->ResetContent();
 HKEY hKey;
RegOpenKeyEx(HKEY_CURRENT_USER,"Software\\ODBC\\ODBC.INI\\ODBC Data Sources",0,KEY_READ,&hKey);
   
    DWord dwKeyCount;
 DWord dwMaxKeyNameLength;

    RegQueryInfoKey(hKey,NULL,NULL,NULL,NULL,NULL,NULL,&dwKeyCount,&dwMaxKeyNameLength,NULL,NULL,NULL);

    char* szKeyName = new char[dwMaxKeyNameLength+1];
    DWord dwKeyName;
    for (long index=0;index<(long)dwKeyCount;index++)
    {
        RegEnumValue(hKey,index,szKeyName,&dwKeyName,NULL,NULL,NULL,NULL);
  CString DSNName;
  DSNName.Format("%s",szKeyName);
  ((CListBox*)GetDlgItem(IDC_DSN_LIST))->AddString(DSNName);
    }
 delete szKeyName;
    RegCloseKey(hKey); 

然後單擊選擇例表框內容,然後把選種的內容記錄成CString m_strDSNName

最後通過ado連接來實現動態連接到數據源

HRESULT hr;
    try
    {    
        hr = m_pConnection.CreateInstance("ADODB.Connection");///創建Connection對象
        if(SUCCEEDED(hr))        

　　{
            hr = m_pConnection->Open("DSN="＋＂_bstr_t(m_strDSNName),"","",0);