dimeby8

Where is wpdmtpextensions.h?

The header file - Wpdmtpextensions.h - has been referenced in several of my posts and is needed to talk MTP to the device through WPD. The header file is not available in the Vista SDK/WDK or the WMP 11 SDK, but is planned for inclusion in the Windows

Creating a WPD playlist object in C#

This is a C# follow-up post on the earlier C++ playlist creation post . Be sure to read the earlier post for background information on playlists and how it stores references. We will also re-use the StringToPropVariant helper function that we defined

Creating WPD PROPVARIANTs in C# without using interop

Previous posts have covered how to create, manage and marshal PROPVARIANTs using interop. Here's a way on how to create a PROPVARIANT without interop. The IPortableDeviceValues interface exposes a SetStringValue method that allows a regular C# string

Marshalling variant properties in C#

This post is a continuation of the one covering WPD property retrieval in C# . That post explained how to marshal strings and the basic int properties. Handling other types such as VT_DATE and VT_BOOL is trickier so I'll try to cover them here. VT_DATE

WPD Content Enumeration in C#

WPD content enumeration in C# is pretty close to the C++ style. Here's a basic example that enumerates the object IDs of the objects present on the device. static void Enumerate( ref PortableDeviceApiLib.IPortableDeviceContent pContent, string parentID,

Setting WPD properties in C#

Since setting a WPD property requires manipulating a PROPVARIANT structure through interop, we must make use of the marshalling rules we set in our last post . We'll take a look at a function that allows string properties to be set. static void SetStringValue(

WPD property retrieval in C#

WPD property values are retrieved as PROPVARIANTs through the WPD API. Unfortunately there is no native support for PROPVARIANTs in C#. To correctly retrieve the property values (or anything that is in a PROPVARIANT) through the WPD API in C#, we must

Where are the WPD property keys in C#?

If you followed the exercise from our first C# post , you must have noticed that the PortableDeviceApi and PortableDeviceTypes typelibs don't expose the WPD property keys such as WPD_OBJECT_ID, WPD_OBJECT_FORMAT, etc. This can be a major blocker since

C# and the WPD API

There currently is no managed/C# flavor of the WPD API. This, of course, doesn't mean that you are locked out from using the WPD API if you want to use C#. Since the API is a set of COM interfaces, we simply have to interop across from C#. Granted it

Help! WPD API calls randomly fail with 0x800700AA (ERROR_BUSY)

If you notice your API calls are randomly failing with HRESULT_FROM_WIN32(ERROR_BUSY) / 0x800700AA / -2147024726, then it's likely that the device driver is indeed busy doing something else. It could be that WMP is syncing content to the device, or maybe

Transferring playlists through WPD

A playlist (.WPL, .M3U, etc.) is a text file which contains a list of filenames. This list is the "playlist". So transferring the playlist should be easy right? Well, yes it is - if you just want to transfer it as a text file... However if you want the

MTP array properties (AINT*/AUINT*) in WPD

MTP allows for a wide range of array-based data types ranging from an array of bytes (AINT8/AUINT8) to an array of GUIDs (AINT128/AUINT128). Check out section 3.2.1 and 3.2.2 in the MTP specification for a complete list and definition. Unfortunately the

Accessing MTP vendor extended properties through WPD

Apart from the standard device and object properties defined in the MTP specification, device vendors are free to add their own properties. The codes for these properties must lie in the vendor-extension range as defined by the MTP spec in section 3.3.1.

Setting WPD properties

The IPortableDeviceProperties::SetValues API can be used to set WPD object properties. The documentation covers the API parameters as well, so we'll skip to the meatier sample. The SetValues API can be used to set multiple properties at the same time.

How to check if a WPD property can be modified

We'll create a little helper function that we can use to figure out if a WPD object property can be modified. All WPD object properties have attributes on them. The MSDN documentation provides a complete list of attributes here . We'll take a look at