COM应该每个线程只初始化一次，但在客户端的生存期内会多次触发 OnExecute 事件。

如果您没有对 TIdTCPServer 使用线程池(通过将 TIdSchedulerOfThreadPool 组件附加到 TIdTCPServer::Scheduler 属性)，那么您可以使用 TIdTCPServer::OnConnect 和 TIdTCPServer::OnDisconnect 事件来初始化/完成您的ADO对象，然后根据需要在 TIdTCPServer::OnExecute 事件中使用它们，例如：

class TMyContextData
public:
    TADOConnection *sql_conn;
    TADOQuery *pos_q;
    TMyContextData();
    ~TMyContextData();
TMyContextData::TMyContextData()
    sql_conn = new TADOConnection(NULL);
    pos_q = new TADOQuery(NULL);
TMyContextData::~TMyContextData()
    delete pos_q;
    delete sql_conn;
void __fastcall TMyForm::tcp_serverConnect(TIdContext *AContext)
    ::CoInitialize(NULL);
    AContext->Data = new TMyContextData;
void __fastcall TMyForm::tcp_serverDisconnect(TIdContext *AContext)
    delete static_cast<TMyContextData*>(AContext->Data);
    AContext->Data = NULL;
    ::CoUninitialize();
void __fastcall TMyForm::tcp_serverExecute(TIdContext *AContext)
    TMyContextData *pData = static_cast<TMyContextData*>(AContext->Data);
    // use pData->sql_conn and pData->pos_q as needed...
 }

或者，改为从 TIdServerContext 派生一个新类：

class TMyContext : public TIdServerContext
public:
    TADOConnection *sql_conn;
    TADOQuery *pos_q;
    __fastcall TMyContext(TIdTCPConnection *AConnection, TIdYarn *AYarn, TIdContextThreadList *AList = NULL);
    __fastcall ~TMyContext();
__fastcall TMyContext::TMyContext(TIdTCPConnection *AConnection, TIdYarn *AYarn, TIdContextThreadList *AList)
    : TIdServerContext(AConnection, AYarn, AList)
    ::CoInitialize(NULL);
    sql_conn = new TADOConnection(NULL);
    pos_q = new TADOQuery(NULL);
__fastcall TMyContext::~TMyContext()
    delete pos_q;
    delete sql_conn;
    ::CoUninitialize();
__fastcall TMyForm::TMyForm(TComponent *Owner)
    : TForm(Owner)
    // do this before activating TIdTCPServer
    tcp_server->ContextClass = __classid(TMyContext);
void __fastcall TMyForm::tcp_serverExecute(TIdContext *AContext)
    TMyContext *pContext = static_cast<TMyContext*>(AContext);
    // use pContext->sql_conn and pContext->pos_q as needed...
}

但是，如果您使用线程池，那么多个客户端可以由同一物理线程服务，因此您应该将COM初始化移动到管理 TIdContext 对象的实际线程对象中(您还应该将您的ADO对象移动到线程中，以便可以将它们重用于多个客户端)，例如：

class TMyADOThread : public TIdThreadWithTask
protected:
    virtual void __fastcall AfterExecute();
    virtual void __fastcall BeforeExecute();
public:
    TADOConnection *sql_conn;
    TADOQuery *pos_q;
    __fastcall TMyADOThread(TIdTask *ATask = NULL, const String AName = "");
__fastcall TMyADOThread::TMyADOThread(TIdTask *ATask, const String AName)
    : TIdThreadWithTask(ATask, AName)
void __fastcall TMyADOThread::BeforeExecute()
    TIdThreadWithTask::BeforeExecute();
    ::CoInitialize(NULL);
    sql_conn = new TADOConnection(NULL);
    pos_q = new TADOQuery(NULL);
void __fastcall TMyADOThread::AfterExecute()
    delete pos_q;
    delete sql_conn;
    ::CoUninitialize();
    TIdThreadWithTask::AfterExecute();
__fastcall TMyForm::TMyForm(TComponent *Owner)
    : TForm(Owner)
    // do this before activating TIdTCPServer
    IdSchedulerOfThreadPool1->ThreadClass = __classid(TMyADOThread);