|Microsoft DirectX 9.0|
The QueryId method retrieves an identifier for the pin.
HRESULT QueryId( LPWSTR *Id );
Pointer to a variable that receives a string containing the pin identifier.
Returns an HRESULT value. Possible values include those shown in the following table.
|E_POINTER||NULL pointer argument.|
|VFW_E_NOT_FOUND||Pin was not found on the filter.|
This method implements the IPin::QueryId method. To construct an identifier string, the pin calls the CSource::FindPinNumber method with itself as the parameter. The FindPinNumber method returns the pin number, indexed from zero. QueryId increments the return value by one and converts the result to a string. For example, the first pin becomes "1"; the second pin becomes "2"; and so forth.
If this method returns VFW_E_NOT_FOUND, it indicates that the filter's array of pins is invalid, presumably caused by a bug in the filter.