Mega Code Archive
Getting notifications from the shell
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How to hook to the shell internal event triggering
If you have ever needed to know when the shell issues an event here is a wrapper around SHChangeNotifyRegister wich allows you to know the kind of event and the file(s) affected, this component is in stage 1 of developement however it offers the whole functionality.
The component itself is composed of enhancements made to TSHChangeNotify component by Elliott Shevin (shevine@aol.com)
By the way here is a list of things you should be aware when using this component for instance restoring an item from the recycle bin to the original location turn on a rename event, while you get a notification over an event you cannot stop it you just get notified of it.
Deleting an Item causes 3 events: OnFileDelete (When the dialog, or the lack of, is displayed normally this is before the deletion of the file) an OnFolderUpdate (after the element is removed and the folder refreshes) and surprise yet another OnFileDelete (after the file has completely been deleted) this behavior is not of the component but of the api it relies on.
Also according to some documentation I read the apis used on this article are entirely undocumented, perhaps it can be possible to stop the event however due to lack of documentation, it is unknown to me.
<-------------- Begin UNIT code ---------------------------->
{$IFNDEF VER80} {$IFNDEF VER90} {$IFNDEF VER93}
{$DEFINE Delphi3orHigher}
{$ENDIF} {$ENDIF} {$ENDIF}
unit ShellNotify;
interface
uses Windows, Messages, SysUtils, Classes, Controls, Forms, Dialogs,
{$IFNDEF Delphi3orHigher} OLE2, {$ELSE} ActiveX, ComObj, {$ENDIF}
ShlObj;
type
NOTIFYREGISTER = record
pidlPath : PItemIDList;
bWatchSubtree : boolean;
end;
PNOTIFYREGISTER = ^NOTIFYREGISTER;
const
SNM_SHELLNOTIFICATION = WM_USER +1;
SHCNF_ACCEPT_INTERRUPTS = $0001;
SHCNF_ACCEPT_NON_INTERRUPTS = $0002;
SHCNF_NO_PROXY = $8000;
type
TNotificationEvent = (neAssociationChange, neAttributesChange,
neFileChange, neFileCreate, neFileDelete, neFileRename,
neDriveAdd, neDriveRemove, neShellDriveAdd, neDriveSpaceChange,
neMediaInsert, neMediaRemove, neFolderCreate, neFolderDelete,
neFolderRename, neFolderUpdate, neNetShare, neNetUnShare,
neServerDisconnect, neImageListChange);
TNotificationEvents = set of TNotificationEvent;
TShellNotificationEvent1 = procedure(Sender: TObject;
Path: String)of Object;
TShellNotificationEvent2 = procedure(Sender: TObject;
path1, path2: String) of Object;
TShellNotification = class(TComponent)
private
fWatchEvents: TNotificationEvents;
fPath: String;
fActive, fWatch: Boolean;
prevPath1, prevPath2: String;
PrevEvent: Integer;
Handle, NotifyHandle: HWND;
fOnAssociationChange: TNotifyEvent;
fOnAttribChange: TShellNotificationEvent2;
FOnCreate: TShellNotificationEvent1;
FOnDelete: TShellNotificationEvent1;
FOnDriveAdd: TShellNotificationEvent1;
FOnDriveAddGui: TShellNotificationEvent1;
FOnDriveRemove: TShellNotificationEvent1;
FOnMediaInsert: TShellNotificationEvent1;
FOnMediaRemove: TShellNotificationEvent1;
FOnDirCreate: TShellNotificationEvent1;
FOnNetShare: TShellNotificationEvent1;
FOnNetUnShare: TShellNotificationEvent1;
FOnRenameFolder: TShellNotificationEvent2;
FOnItemRename: TShellNotificationEvent2;
FOnFolderRemove: TShellNotificationEvent1;
FOnServerDisconnect: TShellNotificationEvent1;
FOnFolderUpdate: TShellNotificationEvent1;
function PathFromPidl(Pidl: PItemIDList): String;
procedure SetWatchEvents(const Value: TNotificationEvents);
function GetActive: Boolean;
procedure SetActive(const Value: Boolean);
procedure SetPath(const Value: String);
procedure SetWatch(const Value: Boolean);
protected
procedure ShellNotifyRegister;
procedure ShellNotifyUnregister;
procedure WndProc(var Message: TMessage);
procedure DoAssociationChange; dynamic;
procedure DoAttributesChange(Path1, Path2: String); dynamic;
procedure DoCreateFile(Path: String); dynamic;
procedure DoDeleteFile(Path: String); dynamic;
procedure DoDriveAdd(Path:String); dynamic;
procedure DoDriveAddGui(Path: String); dynamic;
procedure DoDriveRemove(Path: String); dynamic;
procedure DoMediaInsert(Path: String); dynamic;
procedure DoMediaRemove(Path: String); dynamic;
procedure DoDirCreate(Path: String); dynamic;
procedure DoNetShare(Path: String); dynamic;
procedure DoNetUnShare(Path: String); dynamic;
procedure DoRenameFolder(Path1, Path2: String); dynamic;
procedure DoRenameItem(Path1, Path2: String); dynamic;
procedure DoFolderRemove(Path: String); dynamic;
procedure DoServerDisconnect(Path: String); dynamic;
procedure DoDirUpdate(Path: String); dynamic;
public
constructor Create(AOwner: TComponent); override;
destructor Destroy; override;
published
property Path: String read fPath write SetPath;
property Active: Boolean read GetActive write SetActive;
property WatchSubTree: Boolean read fWatch write SetWatch;
property WatchEvents: TNotificationEvents
read fWatchEvents write SetWatchEvents;
property OnAssociationChange: TNotifyEvent
read fOnAssociationChange write FOnAssociationChange;
property OnAttributesChange: TShellNotificationEvent2
read fOnAttribChange write fOnAttribChange;
property OnFileCreate: TShellNotificationEvent1
read FOnCreate write FOnCreate;
property OnFolderRename: TShellNotificationEvent2
read FOnRenameFolder write FOnRenameFolder;
property OnFolderUpdate: TShellNotificationEvent1
read FOnFolderUpdate write FOnFolderUpdate;
property OnFileDelete: TShellNotificationEvent1
read FOnDelete write FOnDelete;
property OnDriveAdd: TShellNotificationEvent1
read FOnDriveAdd write FOnDriveAdd;
property OnFolderRemove: TShellNotificationEvent1
read FOnFolderRemove write FOnFolderRemove;
property OnItemRename: TShellNotificationEvent2
read FOnItemRename write FOnItemRename;
property OnDriveAddGui: TShellNotificationEvent1
read FOnDriveAddGui write FOnDriveAddGui;
property OnDriveRemove: TShellNotificationEvent1
read FOnDriveRemove write FOnDriveRemove;
property OnMediaInserted: TShellNotificationEvent1
read FOnMediaInsert write FOnMediaInsert;
property OnMediaRemove: TShellNotificationEvent1
read FOnMediaRemove write FOnMediaRemove;
property OnDirCreate: TShellNotificationEvent1
read FOnDirCreate write FOnDirCreate;
property OnNetShare: TShellNotificationEvent1
read FOnNetShare write FOnNetShare;
property OnNetUnShare: TShellNotificationEvent1
read FOnNetUnShare write FOnNetUnShare;
property OnServerDisconnect: TShellNotificationEvent1
read FOnServerDisconnect write FOnServerDisconnect;
end;
function SHChangeNotifyRegister( hWnd: HWND; dwFlags: integer;
wEventMask : cardinal; uMsg: UINT; cItems : integer;
lpItems : PNOTIFYREGISTER) : HWND; stdcall;
function SHChangeNotifyDeregister(hWnd: HWND) : boolean; stdcall;
function SHILCreateFromPath(Path: Pointer; PIDL: PItemIDList;
var Attributes: ULONG):HResult; stdcall;
procedure Register;
implementation
const Shell32DLL = 'shell32.dll';
function SHChangeNotifyRegister; external Shell32DLL index 2;
function SHChangeNotifyDeregister; external Shell32DLL index 4;
function SHILCreateFromPath; external Shell32DLL index 28;
{ TShellNotification }
constructor TShellNotification.Create(AOwner: TComponent);
begin
inherited Create( AOwner );
if not (csDesigning in ComponentState) then
Handle := AllocateHWnd(WndProc);
PrevEvent := 0;
fWatchEvents := [neAssociationChange, neAttributesChange,
neFileChange, neFileCreate, neFileDelete, neFileRename,
neDriveAdd, neDriveRemove, neShellDriveAdd, neDriveSpaceChange,
neMediaInsert, neMediaRemove, neFolderCreate, neFolderDelete,
neFolderRename, neFolderUpdate, neNetShare, neNetUnShare,
neServerDisconnect, neImageListChange];
end;
destructor TShellNotification.Destroy;
begin
if not (csDesigning in ComponentState) then
Active := False;
if Handle <> 0 then DeallocateHWnd( Handle );
inherited Destroy;
end;
procedure TShellNotification.DoAssociationChange;
begin
if Assigned( fOnAssociationChange ) and (neAssociationChange in fWatchEvents) then
fOnAssociationChange( Self );
end;
procedure TShellNotification.DoAttributesChange;
begin
if Assigned( fOnAttribChange ) then
fOnAttribChange( Self, Path1, Path2 );
end;
procedure TShellNotification.DoCreateFile(Path: String);
begin
if Assigned( fOnCreate ) then
FOnCreate(Self, Path)
end;
procedure TShellNotification.DoDeleteFile(Path: String);
begin
if Assigned( FOnDelete ) then
FOnDelete(Self, Path);
end;
procedure TShellNotification.DoDirCreate(Path: String);
begin
if Assigned( FOnDirCreate ) then
FOnDirCreate( Self, Path );
end;
procedure TShellNotification.DoDirUpdate(Path: String);
begin
if Assigned( FOnFolderUpdate ) then
FOnFolderUpdate(Self, Path);
end;
procedure TShellNotification.DoDriveAdd(Path: String);
begin
if Assigned( FOnDriveAdd ) then
FOnDriveAdd(Self, Path);
end;
procedure TShellNotification.DoDriveAddGui(Path: String);
begin
if Assigned( FOnDriveAddGui ) then
FOnDriveAdd(Self, Path);
end;
procedure TShellNotification.DoDriveRemove(Path: String);
begin
if Assigned( FOnDriveRemove ) then
FOnDriveRemove(Self, Path);
end;
procedure TShellNotification.DoFolderRemove(Path: String);
begin
if Assigned(FOnFolderRemove) then
FOnFolderRemove( Self, Path );
end;
procedure TShellNotification.DoMediaInsert(Path: String);
begin
if Assigned( FOnMediaInsert ) then
FOnMediaInsert(Self, Path);
end;
procedure TShellNotification.DoMediaRemove(Path: String);
begin
if Assigned(FOnMediaRemove) then
FOnMediaRemove(Self, Path);
end;
procedure TShellNotification.DoNetShare(Path: String);
begin
if Assigned(FOnNetShare) then
FOnNetShare(Self, Path);
end;
procedure TShellNotification.DoNetUnShare(Path: String);
begin
if Assigned(FOnNetUnShare) then
FOnNetUnShare(Self, Path);
end;
procedure TShellNotification.DoRenameFolder(Path1, Path2: String);
begin
if Assigned( FOnRenameFolder ) then
FOnRenameFolder(Self, Path1, Path2);
end;
procedure TShellNotification.DoRenameItem(Path1, Path2: String);
begin
if Assigned( FOnItemRename ) then
FonItemRename(Self, Path1, Path2);
end;
procedure TShellNotification.DoServerDisconnect(Path: String);
begin
if Assigned( FOnServerDisconnect ) then
FOnServerDisconnect(Self, Path);
end;
function TShellNotification.GetActive: Boolean;
begin
Result := (NotifyHandle <> 0) and (fActive);
end;
function TShellNotification.PathFromPidl(Pidl: PItemIDList): String;
begin
SetLength(Result, Max_Path);
if not SHGetPathFromIDList(Pidl, PChar(Result)) then Result := '';
if pos(#0, Result) > 0 then
SetLength(Result, pos(#0, Result));
end;
procedure TShellNotification.SetActive(const Value: Boolean);
begin
if (Value <> fActive) then
begin
fActive := Value;
if fActive then ShellNotifyRegister else ShellNotifyUnregister;
end;
end;
procedure TShellNotification.SetPath(const Value: String);
begin
if fPath <> Value then
begin
fPath := Value;
ShellNotifyRegister;
end;
end;
procedure TShellNotification.SetWatch(const Value: Boolean);
begin
if fWatch <> Value then
begin
fWatch := Value;
ShellNotifyRegister;
end;
end;
procedure TShellNotification.SetWatchEvents(
const Value: TNotificationEvents);
begin
if fWatchEvents <> Value then
begin
fWatchEvents := Value;
ShellNotifyRegister;
end;
end;
procedure TShellNotification.ShellNotifyRegister;
var
Option: TNotificationEvent;
NotifyRecord: NOTIFYREGISTER;
Flags: DWORD;
Pidl: PItemIDList;
Attributes: ULONG;
const
NotifyFlags: array[TNotificationEvent] of DWORD = (
SHCNE_ASSOCCHANGED, SHCNE_ATTRIBUTES, SHCNE_UPDATEITEM,
SHCNE_CREATE, SHCNE_DELETE, SHCNE_RENAMEITEM, SHCNE_DRIVEADD,
SHCNE_DRIVEREMOVED, SHCNE_DRIVEADDGUI, SHCNE_FREESPACE,
SHCNE_MEDIAINSERTED, SHCNE_MEDIAREMOVED, SHCNE_MKDIR,
SHCNE_RMDIR, SHCNE_RENAMEFOLDER, SHCNE_UPDATEDIR,
SHCNE_NETSHARE, SHCNE_NETUNSHARE, SHCNE_SERVERDISCONNECT,
SHCNE_UPDATEIMAGE);
begin
ShellNotifyUnregister;
if not (csDesigning in ComponentState) and
not (csLoading in ComponentState) then
begin
SHILCreatefromPath( PChar(fPath), Addr(Pidl), Attributes);
NotifyRecord.pidlPath := Pidl;
NotifyRecord.bWatchSubtree := fWatch;
Flags := 0;
for Option := Low(Option) to High(Option) do
if (Option in FWatchEvents) then
Flags := Flags or NotifyFlags[Option];
NotifyHandle := SHChangeNotifyRegister(Handle,
SHCNF_ACCEPT_INTERRUPTS or SHCNF_ACCEPT_NON_INTERRUPTS,
Flags, SNM_SHELLNOTIFICATION, 1, @NotifyRecord);
end;
end;
procedure TShellNotification.ShellNotifyUnregister;
begin
if NotifyHandle <> 0 then
SHChangeNotifyDeregister(NotifyHandle);
end;
procedure TShellNotification.WndProc(var Message: TMessage);
type
TPIDLLIST = record
pidlist : array[1..2] of PITEMIDLIST;
end;
PIDARRAY = ^TPIDLLIST;
var
Path1 : string;
Path2 : string;
ptr : PIDARRAY;
repeated : boolean;
event : longint;
begin
case Message.Msg of
SNM_SHELLNOTIFICATION:
begin
event := Message.LParam and ($7FFFFFFF);
Ptr := PIDARRAY(Message.WParam);
Path1 := PathFromPidl( Ptr^.pidlist[1] );
Path2 := PathFromPidl( Ptr^.pidList[2] );
repeated := (PrevEvent = event)
and (uppercase(prevpath1) = uppercase(Path1))
and (uppercase(prevpath2) = uppercase(Path2));
if Repeated then exit;
PrevEvent := Message.Msg;
prevPath1 := Path1;
prevPath2 := Path2;
case event of
SHCNE_ASSOCCHANGED : DoAssociationChange;
SHCNE_ATTRIBUTES : DoAttributesChange( Path1, Path2);
SHCNE_CREATE : DoCreateFile(Path1);
SHCNE_DELETE : DoDeleteFile(Path1);
SHCNE_DRIVEADD : DoDriveAdd(Path1);
SHCNE_DRIVEADDGUI : DoDriveAddGui(path1);
SHCNE_DRIVEREMOVED : DoDriveRemove(Path1);
SHCNE_MEDIAINSERTED : DoMediaInsert(Path1);
SHCNE_MEDIAREMOVED : DoMediaRemove(Path1);
SHCNE_MKDIR : DoDirCreate(Path1);
SHCNE_NETSHARE : DoNetShare(Path1);
SHCNE_NETUNSHARE : DoNetUnShare(Path1);
SHCNE_RENAMEFOLDER : DoRenameFolder(Path1, Path2);
SHCNE_RENAMEITEM : DoRenameItem(Path1, Path2);
SHCNE_RMDIR : DoFolderRemove(Path1);
SHCNE_SERVERDISCONNECT : DoServerDisconnect(Path);
SHCNE_UPDATEDIR : DoDirUpdate(Path);
SHCNE_UPDATEIMAGE : ;
SHCNE_UPDATEITEM : ;
end;//Case event of
end;//SNM_SHELLNOTIFICATION
end; //case
end;
procedure Register;
begin
RegisterComponents('Shell', [TShellNotification]);
end;
end.
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