Class MFAttributes

The IMFAttributes interface is a general-purpose interface for storing key/value pairs, where the key is a GUID and the value is one of a small number of common data types, including UINT32, UINT64, double, GUID, Unicode string, and BLOB (counted array of UINT8). In addition to the methods inherited from IUnknown, the IMFAttributes interface exposes the following methods.

Inheritance

object

DXComObject

MFAttributes

MFMediaType

MFSample

Implements

IDisposable

Inherited Members

DXComObject.Dispose()

DXComObject.AddRef()

DXComObject.Release()

DXComObject.QueryInterface(in Guid)

DXComObject.Handle

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

object.ToString()

Namespace: JeremyAnsel.DirectX.MediaFoundation

Assembly: JeremyAnsel.DirectX.MediaFoundation.dll

Syntax

[SecurityCritical]
public class MFAttributes : DXComObject, IDisposable

Remarks

The LockStore and UnlockStore calls may not be nested, and may not be called from different threads.

Constructors

MFAttributes(nint)

Initializes a new instance of the MFAttributes class.

Declaration

public MFAttributes(nint comPtr)

Parameters

Type	Name	Description
nint	comPtr

Fields

MFAttributesGuid

The interface GUID.

Declaration

public static readonly Guid MFAttributesGuid

Field Value

Type	Description
Guid

Methods

CopyAllItems(MFAttributes)

CopyAllItems clones all items from the store to the specified store.

Declaration

public void CopyAllItems(MFAttributes pDest)

Parameters

Type	Name	Description
MFAttributes	pDest	pointer to an IMFAttributes interface which will recieve all items from this set.

Remarks

Note that the pDest store must be unlocked in order to retrieve or set items by key.

CopyAllItems is a destructive operation on the destination store. In the event of a failure to copy all items, the state of the pDest store is UNDEFINED. Furthermore, any existing items in the pDest store will be removed prior to copying items from the source store.

DeleteAllItems()

DeleteAllItems removes all values from the attribute set.

Declaration

public void DeleteAllItems()

DeleteItem(Guid)

DeleteItem removes the value associated with the specified key from the attribute set.

Declaration

public void DeleteItem(Guid guidKey)

Parameters

Type	Name	Description
Guid	guidKey	GUID specifying the key.

GetAttribute2UINT32asUINT64(Guid, out uint, out uint)

Declaration

public void GetAttribute2UINT32asUINT64(Guid guidKey, out uint punHigh32, out uint punLow32)

Parameters

Type	Name	Description
Guid	guidKey
uint	punHigh32
uint	punLow32

GetAttributeDouble(Guid, double)

Declaration

public double GetAttributeDouble(Guid guidKey, double fDefault)

Parameters

Type	Name	Description
Guid	guidKey
double	fDefault

Returns

Type	Description
double

GetAttributeRatio(Guid, out uint, out uint)

Declaration

public void GetAttributeRatio(Guid guidKey, out uint punNumerator, out uint punDenominator)

Parameters

Type	Name	Description
Guid	guidKey
uint	punNumerator
uint	punDenominator

GetAttributeSize(Guid, out uint, out uint)

Declaration

public void GetAttributeSize(Guid guidKey, out uint punWidth, out uint punHeight)

Parameters

Type	Name	Description
Guid	guidKey
uint	punWidth
uint	punHeight

GetAttributeUINT32(Guid, uint)

Declaration

public uint GetAttributeUINT32(Guid guidKey, uint unDefault)

Parameters

Type	Name	Description
Guid	guidKey
uint	unDefault

Returns

Type	Description
uint

GetAttributeUINT64(Guid, ulong)

Declaration

public ulong GetAttributeUINT64(Guid guidKey, ulong unDefault)

Parameters

Type	Name	Description
Guid	guidKey
ulong	unDefault

Returns

Type	Description
ulong

GetCount()

GetCount retrieves the number of items currently in the set.

Declaration

public uint GetCount()

Returns

Type	Description
uint	S_OK. The call was successful, and *pcItems contains the number of values in the set.

GetDouble(Guid)

GetDouble retrieves a value of type double corresponding to the given key.

Declaration

public double GetDouble(Guid guidKey)

Parameters

Type	Name	Description
Guid	guidKey	GUID specifying the value to retrieve.

Returns

Type	Description
double	S_OK. Value was found and retrieved successfully. MF_E_INVALIDTYPE Value was found, but is not of type double. MF_E_ATTRIBUTENOTFOUND. No value corresponding to this key is stored in this object.

GetGUID(Guid)

GetGUID retrieve a value of type GUID corresponding to the given key.

Declaration

public Guid GetGUID(Guid guidKey)

Parameters

Type	Name	Description
Guid	guidKey	GUID specifying the value to retrieve.

Returns

Type	Description
Guid	S_OK. Value was found and retrieved successfully. MF_E_INVALIDTYPE Value was found, but is not of type GUID. MF_E_ATTRIBUTENOTFOUND. No value corresponding to this key is stored in this object.

GetItemType(Guid)

GetItemType returns the type of a value from the attributes store that corresponds to the given key (a GUID).

Declaration

public int GetItemType(Guid guidKey)

Parameters

Type	Name	Description
Guid	guidKey	Key corresponding to value to search for

Returns

Type	Description
int	S_OK. The key exists, and the value of pType signifies the type of the item value. MF_E_ATTRIBUTENOTFOUND. No value corresponding to this key is stored in this object.

GetString(Guid)

GetString retrieves a string value corresponding to the given key.

Declaration

public string GetString(Guid guidKey)

Parameters

Type	Name	Description
Guid	guidKey	GUID specifying the value to retrieve.

Returns

Type

Description

string

S_OK. Value was found and retrieved successfully. E_OUTOFMEMORY Value was found, but string length is too large to fit in a UINT32 value. HRESULT_FROM_WIN32( ERROR_INSUFFICIENT_BUFFER ) cchBufSize was not sufficiently large to hold the string value with NULL terminator. In this case, *pcchLength will be set to the length of the string value in chars. The caller will need to allocate a buffer of size at least *ppchLength + 1 chars and call the method again. MF_E_INVALIDTYPE Value was found, but is not of type LPWSTR. MF_E_ATTRIBUTENOTFOUND. No value corresponding to this key is stored in this object.

GetStringLength(Guid)

GetStringLength retrieve the length of a string value corresponding to the given key.

Declaration

public uint GetStringLength(Guid guidKey)

Parameters

Type	Name	Description
Guid	guidKey	GUID specifying the value to check.

Returns

Type	Description
uint	S_OK. Value was found and retrieved successfully. E_OUTOFMEMORY Value was found, but string length is too large to fit in a UINT32 value. MF_E_INVALIDTYPE Value was found, but is not of type LPWSTR. MF_E_ATTRIBUTENOTFOUND. No value corresponding to this key is stored in this object.

GetUINT32(Guid)

GetUINT32 retrieves a value of type UINT32 corresponding to the given key.

Declaration

public uint GetUINT32(Guid guidKey)

Parameters

Type	Name	Description
Guid	guidKey	GUID specifying the value to retrieve.

Returns

Type	Description
uint	S_OK. Value was found and retrieved successfully. MF_E_INVALIDTYPE Value was found, but is not of type UINT32. MF_E_ATTRIBUTENOTFOUND. No value corresponding to this key is stored in this object.

GetUINT64(Guid)

GetUINT64 retrieves a value of type UINT64 corresponding to the given key.

Declaration

public ulong GetUINT64(Guid guidKey)

Parameters

Type	Name	Description
Guid	guidKey	GUID specifying the value to retrieve.

Returns

Type	Description
ulong	S_OK. Value was found and retrieved successfully. MF_E_INVALIDTYPE Value was found, but is not of type UINT64. MF_E_ATTRIBUTENOTFOUND. No value corresponding to this key is stored in this object.

GetUnknown(Guid, Guid)

Declaration

public nint GetUnknown(Guid guidKey, Guid riid)

Parameters

Type	Name	Description
Guid	guidKey
Guid	riid

Returns

Type	Description
nint

LockStore()

LockStore excludes other threads from accessing the set, until such time as UnlockStore is called.

Declaration

public void LockStore()

SetAttribute2UINT32asUINT64(Guid, uint, uint)

Declaration

public void SetAttribute2UINT32asUINT64(Guid guidKey, uint unHigh32, uint unLow32)

Parameters

Type	Name	Description
Guid	guidKey
uint	unHigh32
uint	unLow32

SetAttributeRatio(Guid, uint, uint)

Declaration

public void SetAttributeRatio(Guid guidKey, uint unNumerator, uint unDenominator)

Parameters

Type	Name	Description
Guid	guidKey
uint	unNumerator
uint	unDenominator

SetAttributeSize(Guid, uint, uint)

Declaration

public void SetAttributeSize(Guid guidKey, uint unWidth, uint unHeight)

Parameters

Type	Name	Description
Guid	guidKey
uint	unWidth
uint	unHeight

SetDouble(Guid, double)

SetDouble associates the given double value with the specified key.

Declaration

public void SetDouble(Guid guidKey, double fValue)

Parameters

Type	Name	Description
Guid	guidKey	GUID specifying the key.
double	fValue	Value of the property.

SetGUID(Guid, Guid)

SetGUID associates the given GUID value with the specified key.

Declaration

public void SetGUID(Guid guidKey, Guid guidValue)

Parameters

Type	Name	Description
Guid	guidKey	GUID specifying the key.
Guid	guidValue	Value of the property.

SetString(Guid, string)

SetString associates the given LPWSTR value with the specified key.

Declaration

public void SetString(Guid guidKey, string wszValue)

Parameters

Type	Name	Description
Guid	guidKey	GUID specifying the key.
string	wszValue	Value of the property. WszValue is presumed to be NULL-terminated.

Remarks

Callee will allocate a new buffer and copy the given string, rather than storing a reference to the string passed in. Thus, caller is responsible for freeing any memory which may have been allocated for wszValue.

SetUINT32(Guid, uint)

SetUINT32 associates the given UINT32 value with the specified key.

Declaration

public void SetUINT32(Guid guidKey, uint unValue)

Parameters

Type	Name	Description
Guid	guidKey	GUID specifying the key.
uint	unValue	Value of the property.

SetUINT64(Guid, ulong)

SetUINT64 associates the given UINT64 value with the specified key.

Declaration

public void SetUINT64(Guid guidKey, ulong unValue)

Parameters

Type	Name	Description
Guid	guidKey	GUID specifying the key.
ulong	unValue	Value of the property.

SetUnknown(Guid, nint)

SetUnknown associates the given IUnknown interface pointer value with the specified key.

Declaration

public void SetUnknown(Guid guidKey, nint pUnknown)

Parameters

Type	Name	Description
Guid	guidKey	GUID specifying the key.
nint	pUnknown	Value of the property.

UnlockStore()

UnlockStore allows other threads access to the set, if they were previously denied access via LockStore.

Declaration

public void UnlockStore()

Implements

IDisposable