ShellMenu Class

Properties Methods Events Config Settings Errors

The ShellMenu class enables customizing Shell context menu items and commands.

Syntax

ShellMenu

Remarks

The ShellMenu class provides a simple way to create custom context menu items for any items selected in the Windows Shell. An application may add such menu items to perform global or item-specific operations when a user chooses the command in the context menu displayed by the Shell for the selected items.

The class communicates with the Windows Shell through a proxy DLL that is loaded by Explorer in order to add a custom menu item to context menus and handle invocation of that menu item. The set of modules included in this product is discussed in the Deployment Instructions.

Installation and Initialization

First, call the Install method to register the proxy DLL with the Windows Shell. Installation should be done at least once before using the library on a new system, but may be done several times to update the values of the ProxyPath and Scope properties.

component.Install();

Following the installation, any custom menu items that will be added to the Windows context menu must be registered in the Windows Registry. To do this, call the RegisterMenuItem method for each custom menu item.

component.RegisterMenuItem("MyMenuItem");

The next step is to call Initialize, which will perform the necessary operations to facilitate communication between the system and your code. Initialization only needs to be called once per application launch.

component.Initialize();

Adding Menu Items

Call the Activate method to start serving context menu items and begin handling requests from the Windows Shell. After calling Activate, the MenuItems collection will be populated with the previously registered menu items.

component.Activate(); // If activation was successful this prints out "MyMenuItem" Console.WriteLine(component.MenuItems[0].Verb);

The Windows Registry only stores the unique text identifiers, or verbs, of the added menu items. As such, their additional properties, such as captions and icons are initialized to their default values every time the MenuItems collection is populated. To customize these properties, they must be set manually after calling the Activate method, or by handling the UpdateMenu event. For example:

component.OnUpdateMenu += (s, e) => { int itemCount = 0; foreach (MenuItem item in component.MenuItems) { if (item != null) { item.Caption = "Menu item #" + itemCount; item.Icon = "shell32.dll,-249"; // icon resource string included with the Windows Shell itemCount++; } } };

Once the component is activated, the menu items from the MenuItems collection will appear in the File-Explorer's right-click context menu for any selected Windows Shell items.

Note: Menu items may not be visible in the context menu if their caption property is set to an empty string.

When a user clicks on a context menu item, the InvokeMenu event is fired, and the SelectedItems collection is populated with the Windows Shell items selected in Windows File Explorer. An application may use the context provided by the SelectedItems collection to perform actions specifically tailored to the user's selections. For example:

component.OnInvokeMenu += (s, e) => { if (e.Verb.Equals("MyMenuItem")) { Console.WriteLine("Selected items: "); for (int i = 0; i < component.SelectedItems.Count; i++) { SelectedItem item = component.SelectedItems[i]; Console.WriteLine(item.FileName); } } };

Deactivation and Uninstall

To stop handling Windows Shell requests and render all custom menu items inactive, call the Deactivate method.

component.Deactivate();

Since the menu items registered via the RegisterMenuItem method are not automatically removed from the Windows Registry, it is recommended to call UnregisterMenuItem to unregister each menu item individually during the application's uninstall routine.

component.UnregisterMenuItem("MyMenuItem");

Finally, to detach the component from the Windows Shell and unregister the proxy DLL from the system, call the Uninstall method. Normally, this is done when the application is removed from the system.

component.Uninstall();

PIDLs

A PIDL (or an IDL) is a fundamental Windows Shell concept. At a high level, it is pretty simple, as it is just a value that represents a Windows Shell item in the Windows Shell Namespace. It is a bit like a full filesystem path for a physical file or folder, except that it is a binary object and not a string. The name "PIDL" and "IDL" can be used interchangeably. The leading P stands for pointer, the IDL stands for item identifier list, and PIDL generally refers to an IDL itself rather than the pointer to it.

The below information is provided as a general knowledge. Your application will deal with PIDLs only when they denote some Windows Shell items that are not necessarily a part of the Windows Shell namespace extension that you create. Such PIDLs can be used with the Windows Shell API if you decide to call it directly. When CBFS Shell exposes these PIDL values they will appear hex-encoded. If an application needs to call a shell function, it has to decode the PIDL before calling that function.

Just like a full filesystem path is a list of strings separated by the directory separator (on Windows, it is the \ (backslash) character), a PIDL is a list (L is for list) of Ids (identifiers). Unlike a filesystem path, though, a PIDL is binary, and Ids are separated by a special PIDL separator (two consecutive zero bytes).

Microsoft provides more details about PIDLs here Identifying Namespace Objects.

Verbs

The ShellMenu class is built so that one Explorer command with one GUID is registered in the registry. Verbs are used to identify individual menu items.

A verb is an alphanumeric string that identifies a menu item. Use verbs specific to your application to avoid collisions with other applications. For example, generic words "open" or "edit" are inappropriate because they are or may be used by the Windows Shell or other applications, while "OpenWithMyFineTool" should be ok, as long as "MyFineTool" is not generic.

Each menu item with a distinct verb must be registered before it can be used. This is done by creating the corresponding keys in the registry. Registration is done using the RegisterMenuItem. To remove an item, use UnregisterMenuItem.

In Windows 11, a command and its GUID should additionally be declared in a sparse package manifest that you include into your application. This is done as follows: <?xml version="1.0" encoding="utf-8"?> <Package ... xmlns:desktop4="http://schemas.microsoft.com/appx/manifest/desktop/windows10/4" xmlns:desktop5="http://schemas.microsoft.com/appx/manifest/desktop/windows10/5" IgnorableNamespaces="uap uap2 uap3 rescap desktop desktop4 desktop5 uap10 com"> <Identity Name="..." ProcessorArchitecture="neutral" Publisher="CN=..." Version="1.0.0.0" /> ... <Applications> <Application Id="..." Executable="..." uap10:TrustLevel="mediumIL" uap10:RuntimeBehavior="win32App"> <Extensions> <desktop4:Extension Category="windows.fileExplorerContextMenus"> <desktop4:FileExplorerContextMenus> <desktop5:ItemType Type="*"> <desktop5:Verb Id="Your verb here" Clsid="Your command GUID here" /> <desktop5:Verb Id="Your second verb here" Clsid="Your command GUID here" /> </desktop5:ItemType> </desktop4:FileExplorerContextMenus> </desktop4:Extension> </Extensions> </Application> </Applications> </Package> The command GUID for use in the manifest can be obtained using the CommandGUID configuration setting.

Troubleshooting

Following are some helpful resources for troubleshooting issues related to the display of menu items.

If you are developing your application and you stop and start repeatedly while keeping Windows File Explorer open, there may be a memory/cache issue. To avoid this situation one should terminate Explorer and reopen it.
If your context menu items do not appear at all or an excess number of menu items appear, this may indicate a registration/deregistration issue. Try running the application with administrative privileges.
If you are seeing strange behavior not contained in this list, please reach out to us with a description of the problem and we are happy to help. Our support team is available over email at support@callback.com

Property List

The following is the full list of the properties of the class with short descriptions. Click on the links for further details.


MenuItems	This property contains a collection of registered menu items.
ProxyPath	This property specifies the path to the native proxy DLL.
Scope	This property specifies whether the class is registered for the current user or for all users.
SelectedItems	This property contains a collection of selected Windows Shell items.

Method List

The following is the full list of the methods of the class with short descriptions. Click on the links for further details.


Activate	This method tells the class to start handling the requests sent to the namespace extension.
Config	Sets or retrieves a configuration setting.
Deactivate	This method tells the class to stop handling the requests sent to the namespace extension.
Initialize	This method initializes the core library.
Install	This method registers context menu information to the system.
RegisterMenuItem	This method adds a menu item to the Windows Registry.
Uninstall	This method unregisters context menu information from the system.
UnregisterMenuItem	This method unregisters a previously registered menu item.

Event List

The following is the full list of the events fired by the class with short descriptions. Click on the links for further details.


Error	This event is fired if an unhandled error occurs during an event.
InvokeMenu	This event is fired when an item of the context menu is invoked.
UpdateMenu	This event is fired when the context menu needs to be updated.

Config Settings

The following is a list of config settings for the class with short descriptions. Click on the links for further details.


CanonicalName	A human-readable name of the command.
CommandGUID	A GUID of the Explorer command.
IPCFormat	The fixed name of the RPC endpoint.
IsInstalled	Specifies whether the installation was performed.
ProductGUID	ID of the proxy DLL.
ServerStartArguments	The arguments to pass with the command.
ServerStartCommandLine	The command line to run when the server is not available.
ServerStartOperation	The operation verb.
ServerStartShowOption	Defines how the application windows should be shown.
ServerStartTimeToWait	Optional time to wait before retrying RPC connection.
ServerStartWorkingDirectory	The working directory.
BuildInfo	Information about the product's build.
LicenseInfo	Information about the current license.

MenuItems Property (ShellMenu Class)

This property contains a collection of registered menu items.

Syntax

CBFSShellList<CBFSShellMenuItem>* GetMenuItems();

int cbfsshell_shellmenu_getmenuitemscount(void* lpObj);

char* cbfsshell_shellmenu_getmenuitemcaption(void* lpObj, int menuitemindex);
int cbfsshell_shellmenu_setmenuitemcaption(void* lpObj, int menuitemindex, const char* lpszMenuItemCaption);

int cbfsshell_shellmenu_getmenuitemenabled(void* lpObj, int menuitemindex);
int cbfsshell_shellmenu_setmenuitemenabled(void* lpObj, int menuitemindex, int bMenuItemEnabled);

int cbfsshell_shellmenu_getmenuitemflags(void* lpObj, int menuitemindex);

char* cbfsshell_shellmenu_getmenuitemicon(void* lpObj, int menuitemindex);
int cbfsshell_shellmenu_setmenuitemicon(void* lpObj, int menuitemindex, const char* lpszMenuItemIcon);

char* cbfsshell_shellmenu_getmenuitemverb(void* lpObj, int menuitemindex);

int cbfsshell_shellmenu_getmenuitemvisible(void* lpObj, int menuitemindex);
int cbfsshell_shellmenu_setmenuitemvisible(void* lpObj, int menuitemindex, int bMenuItemVisible);

int GetMenuItemsCount();

QString GetMenuItemCaption(int iMenuItemIndex);
int SetMenuItemCaption(int iMenuItemIndex, QString qsMenuItemCaption);

bool GetMenuItemEnabled(int iMenuItemIndex);
int SetMenuItemEnabled(int iMenuItemIndex, bool bMenuItemEnabled);

int GetMenuItemFlags(int iMenuItemIndex);

QString GetMenuItemIcon(int iMenuItemIndex);
int SetMenuItemIcon(int iMenuItemIndex, QString qsMenuItemIcon);

QString GetMenuItemVerb(int iMenuItemIndex);

bool GetMenuItemVisible(int iMenuItemIndex);
int SetMenuItemVisible(int iMenuItemIndex, bool bMenuItemVisible);

Remarks

This property holds a collection of MenuItem objects.

Customizing Menu Items

When Activate is called to start handling Windows Shell requests the first time after the application is launched, the MenuItems collection gets populated with the menu items, registered in the Windows Registry. The items in the MenuItems collection initially don't contain any values in their properties except for Verb and ParentVerb. An application should fill those items' properties either right after using the Activate method or dynamically, in response to the UpdateMenu event.

Note: Registered menu items may not appear in the context menu if their Caption property is set to an empty string.

This property is read-only and not available at design time.

Data Type

CBFSShellMenuItem

ProxyPath Property (ShellMenu Class)

This property specifies the path to the native proxy DLL.

Syntax

ANSI (Cross Platform)
char* GetProxyPath();
int SetProxyPath(const char* lpszProxyPath);

Unicode (Windows)
LPWSTR GetProxyPath();
INT SetProxyPath(LPCWSTR lpszProxyPath);

char* cbfsshell_shellmenu_getproxypath(void* lpObj);
int cbfsshell_shellmenu_setproxypath(void* lpObj, const char* lpszProxyPath);

QString GetProxyPath();
int SetProxyPath(QString qsProxyPath);

Default Value

Remarks

This property may be used to specify the path to the native proxy DLL, which is loaded by the Windows Shell. The value may be in one of these formats:

The name of the directory with Proxy DLLs. In this case, the class will choose the first DLL with the appropriate architecture.
The full path with the name of the DLL. In this case, just this DLL will be loaded.
The full path with wildcards in the name part (a pattern). In this case, the class will choose the first DLL that matches the passed pattern.

If left empty, the class will automatically attempt to locate the appropriate DLL by searching the directory where the application's executable resides.

Data Type

String

Scope Property (ShellMenu Class)

This property specifies whether the class is registered for the current user or for all users.

Syntax

ANSI (Cross Platform)
int GetScope();
int SetScope(int iScope);

Unicode (Windows)
INT GetScope();
INT SetScope(INT iScope);

Possible Values

IS_ALL_USERS(0), 
IS_CURRENT_USER(1)

int cbfsshell_shellmenu_getscope(void* lpObj);
int cbfsshell_shellmenu_setscope(void* lpObj, int iScope);

int GetScope();
int SetScope(int iScope);

Default Value

Remarks

This property specifies whether the information related to the class is written to the registry for the current user or for all users.

In the latter case, administrative rights are required to successfully execute the Install and Uninstall methods. If the user account of the process that calls these methods does not have such rights, the call will fail with an error.

Data Type

Integer

SelectedItems Property (ShellMenu Class)

This property contains a collection of selected Windows Shell items.

Syntax

CBFSShellList<CBFSShellSelectedItem>* GetSelectedItems();

int cbfsshell_shellmenu_getselecteditemscount(void* lpObj);

char* cbfsshell_shellmenu_getselecteditemfilename(void* lpObj, int selecteditemindex);

char* cbfsshell_shellmenu_getselecteditemid(void* lpObj, int selecteditemindex);

int cbfsshell_shellmenu_getselecteditempidl(void* lpObj, int selecteditemindex, char** lpSelectedItemPIDL, int* lenSelectedItemPIDL);

int GetSelectedItemsCount();

QString GetSelectedItemFileName(int iSelectedItemIndex);

QString GetSelectedItemId(int iSelectedItemIndex);

QByteArray GetSelectedItemPIDL(int iSelectedItemIndex);

Remarks

This property holds a collection of SelectedItem objects, which is populated when a menu is invoked or clicked.

This property is read-only and not available at design time.

Data Type

CBFSShellSelectedItem

Activate Method (ShellMenu Class)

This method tells the class to start handling the requests sent to the namespace extension.

Syntax

ANSI (Cross Platform)
int Activate();

Unicode (Windows)
INT Activate();

int cbfsshell_shellmenu_activate(void* lpObj);

int Activate();

Remarks

This method is used to tell the component to begin handling Windows Shell requests and start firing the corresponding events.

Customizing Menu Items

Note: Registered menu items may not appear in the context menu if their Caption property is set to an empty string.

Menu Item Persistence

When the Deactivate method is called to stop the class, registered menu items will remain in the MenuItems list. If the component is restarted by calling this method after deactivation, the properties of these menu items will not need to be repopulated.

Error Handling (C++)

This method returns a result code; 0 indicates success, while a non-zero error code indicates that this method encountered an error during its execution. If an error occurs, the GetLastError() method can be called to retrieve the associated error message. (Note: This method's result code can also be obtained by calling the GetLastErrorCode() method after it returns.)

Config Method (ShellMenu Class)

Sets or retrieves a configuration setting.

Syntax

ANSI (Cross Platform)
char* Config(const char* lpszConfigurationString);

Unicode (Windows)
LPWSTR Config(LPCWSTR lpszConfigurationString);

char* cbfsshell_shellmenu_config(void* lpObj, const char* lpszConfigurationString);

QString Config(const QString& qsConfigurationString);

Remarks

Config is a generic method available in every class. It is used to set and retrieve configuration settings for the class.

These settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the class, access to these internal properties is provided through the Config method.

To set a configuration setting named PROPERTY, you must call Config("PROPERTY=VALUE"), where VALUE is the value of the setting expressed as a string. For boolean values, use the strings "True", "False", "0", "1", "Yes", or "No" (case does not matter).

To read (query) the value of a configuration setting, you must call Config("PROPERTY"). The value will be returned as a string.

Error Handling (C++)

This method returns a String value; after it returns, call the GetLastErrorCode() method to obtain its result code; 0 indicates success, while a non-zero error code indicates that this method encountered an error during its execution. If an error occurs, the GetLastError() method can be called to retrieve the associated error message.

Deactivate Method (ShellMenu Class)

This method tells the class to stop handling the requests sent to the namespace extension.

Syntax

ANSI (Cross Platform)
int Deactivate();

Unicode (Windows)
INT Deactivate();

int cbfsshell_shellmenu_deactivate(void* lpObj);

int Deactivate();

Remarks

This method tells the component to stop handling Windows Shell requests and stop firing the corresponding events.

Error Handling (C++)

Initialize Method (ShellMenu Class)

This method initializes the core library.

Syntax

ANSI (Cross Platform)
int Initialize();

Unicode (Windows)
INT Initialize();

int cbfsshell_shellmenu_initialize(void* lpObj);

int Initialize();

Remarks

This method initializes the core library and must be called each time the application starts before attempting to use other class's methods. The only exceptions to this are Install, Uninstall, RegisterMenuItem, and UnregisterMenuItem.

If the application explicitly specifies the path to the proxy DLL, it should do this through the ProxyPath property before calling this method.

Error Handling (C++)

Install Method (ShellMenu Class)

This method registers context menu information to the system.

Syntax

ANSI (Cross Platform)
int Install();

Unicode (Windows)
INT Install();

int cbfsshell_shellmenu_install(void* lpObj);

int Install();

Remarks

This method is used to install the native proxy DLL that integrates with the Windows Shell.

Before calling this method, you may change the default values of the ProxyPath, and Scope properties. These values are used during installation.

Registry Scope and User Permissions

The Scope property specifies whether the information is written to the registry for the current user or for all users.

In the latter case, administrative rights are required to execute this method successfully. If the user account of the process that calls this method does not have such rights, the call will fail with an ERROR_PRIVILEGE_NOT_HELD (0x0522) error.

Error Handling (C++)

RegisterMenuItem Method (ShellMenu Class)

This method adds a menu item to the Windows Registry.

Syntax

ANSI (Cross Platform)
int RegisterMenuItem(const char* lpszVerb);

Unicode (Windows)
INT RegisterMenuItem(LPCWSTR lpszVerb);

int cbfsshell_shellmenu_registermenuitem(void* lpObj, const char* lpszVerb);

int RegisterMenuItem(const QString& qsVerb);

Remarks

This method registers a menu item to the Windows Registry. Menu items must be registered before they can be used in a context menu. Normally, this is only needs to be done once during application installation.

The Verb parameter specifies a unique text identifier of the context menu item, further referred to as Verb. A verb is the only aspect of the menu item that gets stored in the Windows Registry.

It is possible to create a menu item with a submenu that contains child items. Note that only one level of submenus is supported on Windows 11, so the class limits addition of items to one level of submenus too.

To create a submenu, when adding a child item, set Verb to the format <ParentVerb>::<Verb>, where ParentVerb denotes the menu item that is a parent for a submenu. Note that the parent's verb is used only in this method to specify the parent, and the class passes just the Verb part to the event handlers. Thus, the verb must be unique across all items added via ShellMenu.

Windows Registry Pollution

Menu items registered with the RegisterMenuItem method are not automatically removed from the Windows Registry. To avoid polluting the Registry, it is recommended to unregister each item before the Uninstall method is called.

Customizing Menu Items

Note: Registered menu items may not appear in the context menu if their Caption property is set to an empty string.

Registry Scope and User Permissions

The Scope property specifies whether the information is written to the registry for the current user or for all users.

Error Handling (C++)

Uninstall Method (ShellMenu Class)

This method unregisters context menu information from the system.

Syntax

ANSI (Cross Platform)
int Uninstall();

Unicode (Windows)
INT Uninstall();

int cbfsshell_shellmenu_uninstall(void* lpObj);

int Uninstall();

Remarks

This method is used to uninstall the proxy DLL that integrates with the Windows Shell from the system.

Before calling this method, you may change the default value of the Scope property.

Windows Registry Pollution

Registry Scope and User Permissions

The Scope property specifies whether the information is written to the registry for the current user or for all users.

Handling Multiple Components

As ShellFolder and ShellMenu classes share a proxy DLL and a product GUID, they store some common information in a registry key. Calling the Uninstall method of one of the components will delete a shared registry key as well.

Each class should be uninstalled properly by calling the corresponding Uninstall method. At the same time, if an application needs to uninstall just one class and keep the other(s), it should call the Uninstall method of that class and then call the Install method of the other classes to restore the common information in the shared registry key.

Error Handling (C++)

UnregisterMenuItem Method (ShellMenu Class)

This method unregisters a previously registered menu item.

Syntax

ANSI (Cross Platform)
int UnregisterMenuItem(const char* lpszVerb);

Unicode (Windows)
INT UnregisterMenuItem(LPCWSTR lpszVerb);

int cbfsshell_shellmenu_unregistermenuitem(void* lpObj, const char* lpszVerb);

int UnregisterMenuItem(const QString& qsVerb);

Remarks

This method is used to remove a menu item that was registered with RegisterMenuItem from the Windows Registry. This should normally be done once per each menu item after the Uninstall method has been called.

The Verb parameter specifies the unique text identifier of the context menu item. If an item is a child in a submenu, this child's own verb is enough (a parent verb should not be specified).

Registry Scope and User Permissions

The Scope property specifies whether the information is written to the registry for the current user or for all users.

Error Handling (C++)

Error Event (ShellMenu Class)

This event is fired if an unhandled error occurs during an event.

Syntax

ANSI (Cross Platform)
virtual int FireError(ShellMenuErrorEventParams *e);

typedef struct {
  int ErrorCode;
  const char *Description;
  int reserved;
} ShellMenuErrorEventParams;


Unicode (Windows)
virtual INT FireError(ShellMenuErrorEventParams *e);

typedef struct {
  INT ErrorCode;
  LPCWSTR Description;
  INT reserved;
} ShellMenuErrorEventParams;

#define EID_SHELLMENU_ERROR 1

virtual INT CBFSSHELL_CALL FireError(INT &iErrorCode, LPSTR &lpszDescription);

class ShellMenuErrorEventParams {
public:
  int ErrorCode();

  const QString &Description();

  int EventRetVal();
  void SetEventRetVal(int iRetVal);
};

// To handle, connect one or more slots to this signal.
void Error(ShellMenuErrorEventParams *e);

// Or, subclass ShellMenu and override this emitter function.
virtual int FireError(ShellMenuErrorEventParams *e) {...}

Remarks

This event fires if an unhandled error occurs. Developers can use this information to track down unhandled errors that occur in the class.

ErrorCode contains an error code and Description contains a textual description of the error.

InvokeMenu Event (ShellMenu Class)

This event is fired when an item of the context menu is invoked.

Syntax

ANSI (Cross Platform)
virtual int FireInvokeMenu(ShellMenuInvokeMenuEventParams *e);

typedef struct {
  const char *Verb;
  int64 Context;
  int reserved;
} ShellMenuInvokeMenuEventParams;


Unicode (Windows)
virtual INT FireInvokeMenu(ShellMenuInvokeMenuEventParams *e);

typedef struct {
  LPCWSTR Verb;
  LONG64 Context;
  INT reserved;
} ShellMenuInvokeMenuEventParams;

#define EID_SHELLMENU_INVOKEMENU 2

virtual INT CBFSSHELL_CALL FireInvokeMenu(LPWSTR &lpszVerb, LONG64 &lContext);

class ShellMenuInvokeMenuEventParams {
public:
  const QString &Verb();

  qint64 Context();

  int EventRetVal();
  void SetEventRetVal(int iRetVal);
};

// To handle, connect one or more slots to this signal.
void InvokeMenu(ShellMenuInvokeMenuEventParams *e);

// Or, subclass ShellMenu and override this emitter function.
virtual int FireInvokeMenu(ShellMenuInvokeMenuEventParams *e) {...}

Remarks

This event is fired when a user invokes, or clicks on, a context menu item that has been registered with RegisterMenuItem. To obtain the list of the Windows Shell items for which the context menu was displayed, use the SelectedItems property.

The Verb parameter contains the unique text identifier of the menu item that was invoked.

The Context parameter is a unique identifier that remains the same across multiple event calls for the same operation. Since the event may fire multiple times for the same operation, its value may be used to avoid performing the same tasks more than once.

UI Considerations

Event handlers are called in the context of threads that run in the MTA (multithreaded apartment) state. This state is not suitable for showing UI elements. Thus, event handlers should create an STA thread and use it to display a needed window. For example:

var thread = new Thread(() => { ... } // "..." is the code that an event handler executes in a helper thread thread.SetApartmentState(ApartmentState.STA); thread.IsBackground = true; thread.Start(); thread.Join(); // optional, if your code should work synchronously

UpdateMenu Event (ShellMenu Class)

This event is fired when the context menu needs to be updated.

Syntax

ANSI (Cross Platform)
virtual int FireUpdateMenu(ShellMenuUpdateMenuEventParams *e);

typedef struct {
  const char *Verb;
  int64 Context;
  int reserved;
} ShellMenuUpdateMenuEventParams;


Unicode (Windows)
virtual INT FireUpdateMenu(ShellMenuUpdateMenuEventParams *e);

typedef struct {
  LPCWSTR Verb;
  LONG64 Context;
  INT reserved;
} ShellMenuUpdateMenuEventParams;

#define EID_SHELLMENU_UPDATEMENU 3

virtual INT CBFSSHELL_CALL FireUpdateMenu(LPWSTR &lpszVerb, LONG64 &lContext);

class ShellMenuUpdateMenuEventParams {
public:
  const QString &Verb();

  qint64 Context();

  int EventRetVal();
  void SetEventRetVal(int iRetVal);
};

// To handle, connect one or more slots to this signal.
void UpdateMenu(ShellMenuUpdateMenuEventParams *e);

// Or, subclass ShellMenu and override this emitter function.
virtual int FireUpdateMenu(ShellMenuUpdateMenuEventParams *e) {...}

Remarks

This event is fired when the system needs to update the context menu before it is displayed. The event fires separately for each menu item that was registered via RegisterMenuItem. An event handler is expected to update the menu item in the MenuItems collection if such an update is required, and such updates will be reflected in the displayed menu. To obtain the list of Windows Shell items for which the context menu is about to be displayed, use the SelectedItems property.

The Verb parameter contains the unique text identifier of the corresponding menu item that may be updated.

UI Considerations

MenuItem Type

Represents a registered menu item.

Syntax

CBFSShellMenuItem (declared in cbfsshell.h)

Remarks

This type represents a registered menu item.

The following fields are available:

Fields

Caption
char*
Default Value: ""

Specifies the menu item's caption.

This field contains the caption or title of the menu item - the text of the item, visible to a user.

Enabled
int
Default Value: TRUE

Specifies that a menu item is enabled.

This field specifies whether the menu item is enabled and can be selected by a user.

Flags
int
Default Value: 0

Flags of the item.

This field is a combination of zero or more flags that specify the attributes of the menu item. The possible flags include:


CMF_DEFAULT	`0x00`	No command flags are set
CMF_HAS_SUBCOMMANDS	`0x01`	Not used.
CMF_HASSPLITBUTTON	`0x02`	A split button is displayed.
CMF_HIDELABEL	`0x04`	The label is hidden.
CMF_ISSEPARATOR	`0x08`	The command is a separator.
CMF_HASLUASHIELD	`0x0010`	A UAC shield is displayed.
CMF_ISDROPDOWN	`0x0080`	Selecting the command opens a drop-down submenu.
CMF_TOGGLEABLE	`0x0100`	The item is a switch.

Icon
char*
Default Value: ""

Specifies the icon of the menu item.

The field may be set to an icon resource string in the standard format, for instance "shell32.dll,-249". When set, this icon will be displayed next to the menu item caption.

Verb
char* (read-only)
Default Value: ""

A verb (text identifier) of the item.

This field contains a Verb, which is a unique text identifier of the item. If a menu item is a child item, this value of this field is <ParentVerb>::<Verb>.

Visible
int
Default Value: TRUE

Specifies that a menu item is visible.

This field specifies whether the menu item is visible and can be seen by a user.

SelectedItem Type

Represents a selected Windows Shell item.

Syntax

CBFSShellSelectedItem (declared in cbfsshell.h)

Remarks

This type represents a Windows Shell item in the list of items selected in ShellMenu.

The following fields are available:

FileName

PIDL

Fields

FileName
char* (read-only)
Default Value: ""

Contains a file name of the selected item.

If an item is a filesystem object and its PIDL can be resolved to a filesystem path, this field contains a full path on the filesystem; otherwise, the field is empty.

Id
char* (read-only)
Default Value: ""

Contains an Id of the selected item.

If a selected item comes from within the virtual Windows Shell folder managed by the ShellFolder class, this field contans an application-defined Id. In other cases, this field is empty and the application may use the PIDL field to identify the item.

PIDL
char* (read-only)
Default Value:

Contains a PIDL of the selected item.

This field contains the PIDL of the selected item.

CBFSShellList Type

Syntax

CBFSShellList<T> (declared in cbfsshell.h)

Remarks

CBFSShellList is a generic class that is used to hold a collection of objects of type T, where T is one of the custom types supported by the ShellMenu class.

Methods

GetCount	This method returns the current size of the collection. int GetCount() {}
SetCount	This method sets the size of the collection. This method returns `0` if setting the size was successful; or `-1` if the collection is `ReadOnly`. When adding additional objects to a collection call this method to specify the new size. Increasing the size of the collection preserves existing objects in the collection. int SetCount(int count) {}
Get	This method gets the item at the specified position. The `index` parameter specifies the index of the item in the collection. This method returns `NULL` if an invalid `index` is specified. T* Get(int index) {}
Set	This method sets the item at the specified position. The `index` parameter specifies the index of the item in the collection that is being set. This method returns `-1` if an invalid `index` is specified. Note: Objects created using the `new` operator must be freed using the `delete` operator; they will not be automatically freed by the class. T* Set(int index, T* value) {}

Config Settings (ShellMenu Class)

The class accepts one or more of the following configuration settings. Configuration settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the class, access to these internal properties is provided through the Config method.

ShellMenu Config Settings

CanonicalName: A human-readable name of the command.

This configuration setting is used to specify a human-readable name of the Explorer command as this command is written in the registry in the form of a GUID (the value of the GUID can be retrieved via the CommandGUID setting). The default value is "CBFS Shell context menu extension". Adjust this setting before calling the Install method. If not set, the default value is used during the installation.

CommandGUID: A GUID of the Explorer command.

This read-only configuration setting contains a GUID of the Explorer command that is used to register all menu items in the registry. A human-readable canonical name for the GUID may be specified using the CanonicalName config setting.

IPCFormat: The fixed name of the RPC endpoint.

If the Windows Shell and the server operate in different desktop sessions, set this configuration before installing the native proxy DLL.

IsInstalled: Specifies whether the installation was performed.

This configuration setting returns true if the class finds the required registry entries, put there by a previous call to the Install method; otherwise, false is returned. In the latter case, an application should use the Install method again.

ProductGUID: ID of the proxy DLL.

A product GUID (also known as project ID) is used to distinguish among various installations performed by different applications. The GUID of the Explorer command (CommandGUID) is derived from this ID.

ServerStartArguments: The arguments to pass with the command.