ICommandImpl Class
Provides implementation for the ICommand interface.
Syntax
template <class T, class CommandBase = ICommand>
class ATL_NO_VTABLE ICommandImpl : public CommandBase
Parameters
T
Your class, derived from ICommandImpl.
CommandBase
A command interface. The default is ICommand.
Requirements
Header: atldb.h
Members
Methods
| Name | Description |
|---|---|
| Cancel | Cancels the current command execution. |
| CancelExecution | Cancels the current command execution. |
| CreateRowset | Creates a rowset object. |
| Execute | Executes the command. |
| GetDBSession | Returns an interface pointer to the session that created the command. |
| ICommandImpl | The constructor. |
Data Members
| Name | Description |
|---|---|
| m_bCancel | Indicates whether the command is to be canceled. |
| m_bCancelWhenExecuting | Indicates whether the command is to be canceled when executing. |
| m_bIsExecuting | Indicates whether the command is currently executing. |
Remarks
A mandatory interface on the command object.
ICommandImpl::Cancel
Cancels the current command execution.
Syntax
STDMETHOD(Cancel)();
Remarks
See ICommand::Cancel in the OLE DB Programmer's Reference.
ICommandImpl::CancelExecution
Cancels the current command execution.
Syntax
HRESULT CancelExecution();
ICommandImpl::CreateRowset
Called by Execute to create a single rowset.
Syntax
template template <class RowsetClass>
HRESULT CreateRowset(IUnknown* pUnkOuter,
REFIID riid,
DBPARAMS* pParams,
DBROWCOUNT* pcRowsAffected,
IUnknown** ppRowset,
RowsetClass*& pRowsetObj);
Parameters
RowsetClass
A template class member representing the user's rowset class. Usually generated by the wizard.
pUnkOuter
[in] A pointer to the controlling IUnknown interface if the rowset is being created as part of an aggregate; otherwise, it is null.
riid
[in] Corresponds to riid in ICommand::Execute.
pParams
[in/out] Corresponds to pParams in ICommand::Execute.
pcRowsAffected
Corresponds to pcRowsAffected in ICommand::Execute.
ppRowset
[in/out] Corresponds to ppRowset in ICommand::Execute.
pRowsetObj
[out] A pointer to a rowset object. Typically this parameter is not used, but it can be used if you must perform more work on the rowset before passing it to a COM object. The lifetime of pRowsetObj is bound by ppRowset.
Return Value
A standard HRESULT value. See ICommand::Execute for a list of typical values.
Remarks
To create more than one rowset, or to provide your own conditions for creating different rowsets, place different calls to CreateRowset from within Execute.
See ICommand::Execute in the OLE DB Programmer's Reference.
ICommandImpl::Execute
Executes the command.
Syntax
HRESULT Execute(IUnknown* pUnkOuter,
REFIID riid,
DBPARAMS* pParams,
DBROWCOUNT* pcRowsAffected,
IUnknown** ppRowset);
Parameters
See ICommand::Execute in the OLE DB Programmer's Reference.
Remarks
The outgoing interface requested will be an interface acquired from the rowset object that this function creates.
Execute calls CreateRowset. Override the default implementation to create more than one rowset or to provide your own conditions for creating different rowsets.
ICommandImpl::GetDBSession
Returns an interface pointer to the session that created the command.
Syntax
STDMETHOD (GetDBSession) (REFIID riid,
IUnknown** ppSession);
Parameters
See ICommand::GetDBSession in the OLE DB Programmer's Reference.
Remarks
Useful for retrieving properties from the session.
ICommandImpl::ICommandImpl
The constructor.
Syntax
ICommandImpl();
ICommandImpl::m_bCancel
Indicates whether the command is canceled.
Syntax
unsigned m_bCancel:1;
Remarks
You can retrieve this variable in the Execute method of your command class and cancel as appropriate.
ICommandImpl::m_bCancelWhenExecuting
Indicates whether the command can be canceled when executing.
Syntax
unsigned m_bCancelWhenExecuting:1;
Remarks
Defaults to true (can be canceled).
ICommandImpl::m_bIsExecuting
Indicates whether the command is currently executing.
Syntax
unsigned m_bIsExecuting:1;
Remarks
The Execute method of your command class can set this variable to true.
See also
OLE DB Provider Templates
OLE DB Provider Template Architecture