/// <summary>
/// Method attempts to find that parent of a known folder by looking at the
/// ParentId field in the associated <see cref="KnownFolderProperties"/> object
/// and returns the new parent and child <see cref="IdList"/>s on success.
/// </summary>
/// <param name="ashellListId"></param>
/// <param name="parentList"></param>
/// <param name="relativeChild"></param>
/// <returns>True if known folder parent was available in ParentId field,
/// otherwise false.</returns>
public static bool GetParentChildIdList(IdList ashellListId
, out IdList parentList
, out IdList relativeChild)
{
parentList = null;
relativeChild = null;
relativeChild = ashellListId.GetRelativeChildId();
parentList = ashellListId.GetParentId();
// Get Parent Id which is always the first part minus last id in the sequence
if (parentList != null)
{
return(true);
}
// Try to find parent through known folder information lookup
using (KnownFolderNative kf = KnownFolderHelper.FromPIDL(ashellListId))
{
if (kf != null)
{
var props = KnownFolderHelper.GetFolderProperties(kf.Obj);
if (props.Parent != null)
{
if ((parentList = IdList.FromKnownFolderGuid(props.ParentId)) != null)
{
return(true);
}
}
}
}
// Just return the desktop as parent if the given item has no more parents
using (var desktop = KnownFolderHelper.FromKnownFolderGuid(new Guid(KF_ID.ID_FOLDERID_Desktop)))
{
IntPtr desktopPtr = default(IntPtr);
try
{
desktopPtr = desktop.KnownFolderToPIDL();
if (desktopPtr != default(IntPtr))
{
parentList = IdList.Create(PidlManager.Decode(desktopPtr));
return(true);
}
}
finally
{
if (desktopPtr != default(IntPtr))
{
desktopPtr = PidlManager.ILFree(desktopPtr);
}
}
}
return(false);
}
/// <summary>
/// Gets the parent IdList (parent PIDL) if available and a
/// relative child idList (relative child PIDL).
/// </summary>
/// <param name="originalPath"></param>
/// <param name="parentList"></param>
/// <param name="relativeChild"></param>
/// <returns></returns>
public static bool GetParentIdListFromPath(string originalPath
, out IdList parentList
, out IdList relativeChild)
{
parentList = null;
relativeChild = null;
if (string.IsNullOrEmpty(originalPath))
{
return(false);
}
// Desktop is the root of the shell and does not have a parent
if (originalPath.Equals(KF_IID.ID_FOLDERID_Desktop, StringComparison.InvariantCultureIgnoreCase))
{
return(true);
}
IntPtr apidl = default(IntPtr);
try
{
// Decode the pidl for this path into a list of ShellIds
apidl = PidlManager.GetPIDLFromPath(originalPath);
if (apidl == default(IntPtr)) // Cannot resolve this PIDL
{
return(false);
}
// Convert PIDL into list of shellids and remove last id
var ashellListId = PidlManager.Decode(apidl);
return(GetParentChildIdList(IdList.Create(ashellListId),
out parentList, out relativeChild));
}
finally
{
apidl = PidlManager.ILFree(apidl);
}
}
/// <summary>
/// Returns an <see cref="IdList"/> (PIDL) for a known folder given a
/// globally unique identifier.
/// </summary>
/// <param name="knownfolderId">A GUID for the requested known folder.</param>
/// <returns>A known folder representing the specified name.</returns>
/// <exception cref="System.ArgumentException">Thrown if the given Known Folder ID is invalid.</exception>
public static IdList FromKnownFolderGuid(Guid knownfolderId)
{
using (KnownFolderNative KF = KnownFolderHelper.FromKnownFolderGuid(knownfolderId))
{
if (KF != null)
{
IntPtr parentPidl = default(IntPtr);
try
{
parentPidl = KF.KnownFolderToPIDL();
// Convert PIDL into list of shellids and remove last id
return(IdList.Create(PidlManager.Decode(parentPidl)));
}
finally
{
parentPidl = PidlManager.ILFree(parentPidl);
}
}
}
return(null);
}