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Enumerating Services and Storages

The collections of Services and Storages on a device are accessed through the read-only Device object properties of Device.Services and Device.Storages. These collections can be enumerated directly through these properties, or they can be extracted into servicesCollection and storagesCollection objects and enumerated separately.

Enumerating Services

There are four ways to enumerate services: by index into a services collection, by Persistent Unique ID (PUID), by Object identifier (ObjectID), and by service type.

Enumerating a Service by an Index into the Services Collection

Individual services in a services collection can be accessed by using a zero-based numeric index. The following examples show how to retrieve a specific service by using an index.

Retrieve a service directly from the services collection in the Device object by using an index.


var aService = DeviceObject.Services[0];

Retrieve a separate collection of all services on a device, and then access a specific service by indexing into the collection.


var services = DeviceObject.Services;

for (i=0; i < services.Count; i++)
{
    var aService = services[i];

    // Do something with aService.
}

Enumerating a Service by PUID

A PUID is a string that uniquely identifies a service on the device. The PUID for a specific service can be obtained by using the WPD Automation name ObjectPersistentUniqueID that corresponds to the WPD PROPERTYKEY WPD_OBJECT_PERSISTENT_UNIQUE_ID; for example:

var servicePUID = service.ObjectPersistentUniqueID;

The following examples show how to retrieve a specific service by using its PUID.

Retrieve a service directly from the services collection in the Device object by using its PUID.



var servicePUID = DeviceObject.Services[0].ObjectPersistentUniqueId;
var service = DeviceObject.Services[servicePUID];

Retrieve a separate collection of all services on a device, and then access a specific service by using its PUID.


var services = DeviceObject.Services;
var servicePUID = services[0].ObjectPersistentUniqueId;

// Any service can be accessed by using its PUID.
var service = services[servicePUID];

Enumerating a Service by ObjectID

An ObjectID is a string that uniquely identifies a service object on the device. The ObjectId of a specific service can be obtained by using the WPD Automation name ObjectId that corresponds to the WPD PROPERTYKEY WPD_OBJECT_ID; for example:

var serviceObjectId = service.ObjectId;

The following example shows how to retrieve a specific service by using its ObjectID.

Retrieve a service directly from the services collection in the Device object by using its ObjectID.



var objectID = DeviceObject.Services[0].ObjectId;
var service = DeviceObject.Services[objectID];

Retrieve a separate collection of all services on a device, and then access a specific service by using its ObjectID.


var services = DeviceObject.Services;
var serviceID = services[0].ObjectId;

// Any service can be accessed by using its ObjectID.
var service = services[serviceID];

Enumerating a Service by Service Type

The Device object also exposes the GetServicesByType method to retrieve a collection of services by Service Type. This method is useful if you do not know the PUID or ObjectID of a particular service, or if you want to create separate collections of services based on type. After you retrieve the collection with the GetServicesByType method, each item in the collection is accessed by index, as shown in the following example.

Retrieve a collection of services for a particular Service Type, and then access each item in the collection by index.


var ringtoneServices = DeviceObject.GetServicesByType("{D0EACE0E-707D-4106-8D38-4F60E6A9F8E}");

for (i=0; i < ringtoneServices.Count; i++)
{
    var aRingtoneService = ringtoneServices[i];

    // Do something with aRingtoneService.
}

Enumerating Storages

Individual storages in the Device.Storages collection or in a separate storagesCollection are enumerated by using a zero-based numeric index, by PUID, and by ObjectID.

Enumerating a Storage by an Index into the Storages Collection

The following examples show how to retrieve a specific storage by using an index.

Retrieve a storage directly from the storages collection in the Device object by using an index.


var aStorage = DeviceObject.Storages[0];

Retrieve a separate collection of all the storages on a device, and then access a specific storage by indexing into the collection.


var storages = DeviceObject.Storages;

for (i=0; i < storages.Count; i++)
{
    var aStorage = storages[i];

    // Do something with aStorage.
}

Enumerating a Storage by PUID

A PUID is a string that uniquely identifies a storage on the device. The PUID for a specific storage can be obtained by using the WPD Automation name ObjectPersistentUniqueID that corresponds to the WPD PROPERTYKEY WPD_OBJECT_PERSISTENT_UNIQUE_ID. The following examples show how to retrieve a specific storage by using its PUID.

Retrieve a storage directly from the storages collection in the Device object by using its PUID.



var storagePUID = DeviceObject.Storages[0].ObjectPersistentUniqueId;
var storage = DeviceObject.Storages[storagePUID];

Retrieve a separate collection of all storages on a device, and then access a specific storage by using its PUID.


var storages = DeviceObject.Storages;
var storagePUID = storages[0].ObjectPersistentUniqueId;

// Any storage can be accessed by using its PUID.
var storage = storages[storagePUID];

Enumerating a Storage by ObjectID

An ObjectID is a string that uniquely identifies a storage object on the device. The ObjectId of a specific storage can be obtained by using the WPD Automation name ObjectId that corresponds to the WPD PROPERTYKEY WPD_OBJECT_ID. The following example shows how to retrieve a specific storage by using its ObjectID.

Retrieve a storage directly from the storages collection in the Device object by using its ObjectID.



var storageID = DeviceObject.Storages[0].ObjectId;
var storage = DeviceObject.Storages[objectID];

Retrieve a separate collection of all storages on a device, and then access a specific storage by using its ObjectID.


var storages = DeviceObject.Storages;
var storageID = storages[0].ObjectId;

// Any storage can be accessed by using its ObjectID.
var storage = storages[storageID];

Related topics

Device Object
Names for WPD PROPERTYKEYs
Service Object
servicesCollection Object
Storage Object
storagesCollection Object
WPD Automation Programming Guide

 

 

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