WdfRegistryQueryMultiString method

[Applies to KMDF and UMDF]

The WdfRegistryQueryMultiString method retrieves the strings that are currently assigned to a specified multi-string registry value, creates a framework string object for each string, and adds each string object to a specified object collection.

Syntax


NTSTATUS WdfRegistryQueryMultiString(
  [in]            WDFKEY                 Key,
  [in]            PCUNICODE_STRING       ValueName,
  [in, optional]  PWDF_OBJECT_ATTRIBUTES StringsAttributes,
  [in]            WDFCOLLECTION          Collection
);

Parameters

Key [in]

A handle to a registry-key object that represents an opened registry key.

ValueName [in]

A pointer to a UNICODE_STRING structure that contains a value name.

StringsAttributes [in, optional]

A pointer to a WDF_OBJECT_ATTRIBUTES structure that contains object attributes for each new string object. This parameter is optional and can be WDF_NO_OBJECT_ATTRIBUTES.

Collection [in]

A handle to a driver-supplied framework collection object.

Return value

WdfRegistryQueryMultiString returns STATUS_SUCCESS if the operation succeeds. Otherwise, the method might return one of the following values:

Return codeDescription
STATUS_INVALID_DEVICE_REQUEST

WdfRegistryQueryMultiString was not called at IRQL = PASSIVE_LEVEL.

STATUS_INVALID_PARAMETER

An invalid parameter was specified.

STATUS_INSUFFICIENT_RESOURCES

A string object could not be allocated.

STATUS_ACCESS_DENIED

The driver did not open the registry key with KEY_QUERY_VALUE, KEY_READ, or KEY_ALL_ACCESS access.

STATUS_OBJECT_TYPE_MISMATCH

The data type of the registry value that the ValueName parameter specified was not REG_MULTI_SZ.

STATUS_OBJECT_NAME_NOT_FOUND

The registry value was not available.

 

For a list of other return values that the WdfRegistryQueryMultiString method might return, see Framework Object Creation Errors.

This method also might return other NTSTATUS values.

A bug check occurs if the driver supplies an invalid object handle.

Remarks

Before your driver calls WdfRegistryQueryMultiString, it must call WdfCollectionCreate to create a collection object.

After WdfRegistryQueryMultiString returns, the driver can call WdfCollectionGetCount to obtain the number of retrieved strings and WdfCollectionGetItem to obtain string objects from the collection.

If the collection contains objects before the driver calls the WdfRegistryQueryMultiString method, the method does not remove those objects or change their index values. The new objects are appended to the end of the collection.

To obtain a string from a string object, the driver can call WdfStringGetUnicodeString.

For more information about registry-key objects, see Using the Registry in Framework-Based Drivers.

Examples

The following code example creates a collection object, initializes a WDF_OBJECT_ATTRIBUTES structure so that the collection object will be the parent of all of the string objects that the framework creates for the collection, and retrieves the strings from a multi-string registry value. Finally, the example obtains the number of string objects that the framework added to the collection.


WDF_OBJECT_ATTRIBUTES stringAttributes;
WDFCOLLECTION col;
NTSTATUS status;
ULONG count;
DECLARE_CONST_UNICODE_STRING(valueMultiSz, VALUE_MULTI_SZ);

status = WdfCollectionCreate(
                             NULL,
                             &col
                             );
ASSERT(NT_SUCCESS(status));

WDF_OBJECT_ATTRIBUTES_INIT(&stringAttributes);
stringAttributes.ParentObject = col;

status = WdfRegistryQueryMultiString(
                                     Key,
                                     &valueMultiSzEmpty,
                                     &stringAttributes,
                                     col
                                     );

count = WdfCollectionGetCount(col);

Requirements

Target platform

Universal

Minimum KMDF version

1.0

Minimum UMDF version

2.0

Header

Wdfregistry.h (include Wdf.h)

Library

Wdf01000.sys (KMDF);
WUDFx02000.dll (UMDF)

IRQL

PASSIVE_LEVEL

DDI compliance rules

DriverCreate, KmdfIrql, KmdfIrql2

See also

UNICODE_STRING
WDF_OBJECT_ATTRIBUTES
WdfCollectionCreate
WdfCollectionGetCount
WdfCollectionGetItem
WdfRegistryQueryMemory
WdfRegistryQueryString
WdfRegistryQueryUnicodeString
WdfRegistryQueryULong
WdfRegistryQueryValue
WdfStringGetUnicodeString

 

 

Send comments about this topic to Microsoft

Show:
© 2015 Microsoft