IKsPropertySet Interface

The IKsPropertySet interface enables you to set and retrieve device properties.

When to Implement

Implement this interface on any pin to expose its properties and to enable its properties to be changed.

When to Use

Use this interface in your application or filter to access device properties.

Methods in Vtable Order

IUnknown methods	Description
QueryInterface	Returns pointers to supported interfaces.
AddRef	Increments the reference count.
Release	Decrements the reference count.

IKsPropertySet methods	Description
Set	Sets a property identified by a property set GUID and a property ID.
Get	Retrieves a property identified by a property set GUID and a property ID.
QuerySupported	Determines whether an object supports a property set.

---

IKsPropertySet::Get

Retrieves a property identified by a property set GUID and a property ID.

HRESULT Get(
  REFGUID guidPropSet,
  DWORD dwPropID,
  LPVOID pInstanceData,
  DWORD cbInstanceData,
  LPVOID pPropData,
  DWORD cbPropData,
  DWORD *pcbReturned
  );

Parameters

guidPropSet

[in] Property set GUID.

dwPropID

[in] Identifier of the property within the property set.

pInstanceData

[out, size_is(cbInstanceData)] Pointer to instance data for the property.

cbInstanceData

[in] Number of bytes in the buffer to which pInstanceData points.

pPropData

[out, size_is(cbPropData)] Pointer to the retrieved buffer, which contains the value of the property.

cbPropData

[in] Number of bytes in the buffer to which pPropData points.

pcbReturned

[out] Pointer to the number of bytes returned in the buffer to which pPropData points.

Return Values

Returns an HRESULT value that depends on the implementation of the interface.

The current DirectShow implementation returns E_PROP_SET_UNSUPPORTED if the property set is not supported or E_PROP_ID_UNSUPPORTED if the property ID is not supported for the specified property set.

Remarks

To retrieve a property, allocate a buffer which this method will then fill in. To determine the necessary buffer size, specify NULL for pPropData and zero (0) for cbPropData. This method returns the necessary buffer size in pcbReturned.

---

IKsPropertySet::QuerySupported

Determines whether an object supports a property set.

HRESULT QuerySupported(
  REFGUID guidPropSet,
  DWORD dwPropID,
  DWORD *pTypeSupport
  );

Parameters

guidPropSet

[in] Property set GUID.

dwPropID

[in] Identifier of the property within the property set.

pTypeSupport

[out] Pointer to a value in which to store flags indicating the support provided by the driver. Supported flags include the following:

Value	Meaning
KSPROPERTY_SUPPORT_GET	You can retrieve the property by calling the IKsPropertySet::Get method.
KSPROPERTY_SUPPORT_SET	You can change the property by calling IKsPropertySet::Set.

Return Values

Returns an HRESULT value that depends on the implementation of the interface.

The return values for the current DirectShow implementation include the following:

Value	Meaning
E_NOTIMPL	Property set is not supported.
E_PROP_ID_UNSUPPORTED	Property ID is not supported for the specified property set.
E_PROP_SET_UNSUPPORTED	Property set is not supported.
S_OK	Specified property set and property ID combination is supported.

---

IKsPropertySet::Set

Sets a property identified by a property set GUID and a property ID.

HRESULT Set(
  REFGUID guidPropSet,
  DWORD dwPropID,
  LPVOID pInstanceData,
  DWORD cbInstanceData,
  LPVOID pPropData,
  DWORD cbPropData
  );

Parameters

guidPropSet

[in] Property set GUID.

dwPropID

[in] Identifier of the property within the property set.

pInstanceData

[out, size_is(cbInstanceData)] Pointer to instance data for the property.

cbInstanceData

[in] Number of bytes in the buffer to which pInstanceData points.

pPropData

[out, size_is(cbPropData)] Pointer to the retrieved buffer, which contains the value of the property.

cbPropData

[in] Number of bytes in the buffer to which pPropData points.

Return Values

Returns an HRESULT value that depends on the implementation of the interface.

The current DirectShow implementation returns E_PROP_SET_UNSUPPORTED if the property set is not supported or E_PROP_ID_UNSUPPORTED if the property ID is not supported for the specified property set.

© 1997 Microsoft Corporation. All rights reserved. Terms of Use.