IViewHelper::GetConnectedIDs method

Articolo
10/17/2017

The GetConnectedIDs method retrieves, for a given adapter, an array of identifiers for either targets or sources.

Syntax

HRESULT GetConnectedIDs(
  [in]      LPCWSTR wszAdaptorName,
  [in, out] ULONG   *pulCount,
  [in, out] ULONG   *pulID,
  [in]      ULONG   ulFlags
);

Parameters

wszAdaptorName [in]
[in] A NULL-terminated string that indicates the name of the adapter to retrieve identifiers for. The adapter name is obtained from the DeviceKey member of the DISPLAY_DEVICE structure. The adapter name was set in and returned from a call to the EnumDisplayDevices function. For more information about DISPLAY_DEVICE and EnumDisplayDevices, see the Microsoft Windows SDK documentation.
pulCount [in, out]
[in,out] A pointer to a variable that receives the number of entries in the array that will be subsequently returned in the buffer that pulID points to. For more information about how array entries are retrieved, see the Remarks section.
pulID [in, out]
[in,out] A pointer to a buffer that receives the array of identifiers for the targets or sources.

ulFlags [in]
[in] A flag value that identifies the type of identifiers to retrieve. ulFlags can be set to one of the following values.

Value	Meaning
GETCONNECTEDIDS_TARGET (0)	The array that the pulID parameter points to should contain connected (though not necessarily active) targets.
GETCONNECTEDIDS_SOURCE (1)	The array that pulID points to should contain available sources.

Return value

The GetConnectedIDs method returns one of the following values:

Return code	Description
S_OK	GetConnectedIDs successfully retrieved identifiers.
E_INVALIDARG	The ulFlags parameter contained an unknown value.
E_POINTER	One or more of the pointer parameters is set to NULL when it should not be set to NULL.
ERROR_GRAPHICS_INVALID_DISPLAY_ADAPTER	GetConnectedIDs could not match the adapter name in the wszAdaptorName string to an existing graphics adapter's name.
ERROR_GRAPHICS_OPM_PARAMETER_ARRAY_TOO_SMALL	The array that was passed in the pulID parameter cannot hold all of the data that GetConnectedIDs must insert. TMM will then query for the number of array elements again.
*Any other error code (that is defined in Winerror.h) will cause TMM to not act on the retrieved data.*

Remarks

GetConnectedIDs is used to determine if two monitors that are connected to a graphics adapter can be placed into clone view.

To qualify as a target, a monitor or other display device must be connected to the computer. For example, consider a graphics adapter with a Digital Video Interface (DVI) connector that supports output through DVI analog and DVI digital. GetConnectedIDs reports the target identifier of the DVI analog or DVI digital output connector only if a monitor is plugged into that connector. Therefore, a report of targets is not a report of all of the outputs that are available through the video ports. Rather, it is a report of what is physically attached to the graphics adapter. Each monitor is reported as a target whether the monitor is active or not.

In the first call to GetConnectedIDs, the pulID parameter is set to NULL, and the number of entries in the array of identifiers is retrieved in the variable that the pulCount parameter points to. In the second call to GetConnectedIDs, the number of entries that was retrieved in the first call is passed in the variable that pulCount points to, and an allocated array is passed to pulCount. This allocated array receives the identifiers of the targets or sources.

GetConnectedIDs is called when a new second monitor is detected. The IViewHelper::SetActiveTopology method must then be called to set the display on the adapter to clone view. The adapter name is the string that was obtained from the DeviceKey member of the DISPLAY_DEVICE structure in a call to the EnumDisplayDevices function. For more information about DISPLAY_DEVICE and EnumDisplayDevices, see the Windows SDK documentation.

Requirements

End of support	Windows 7
Header	Cloneviewhelper.h (include Cloneviewhelper.h)

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