Contains controls which display files and directories.

shellctrls.pas contains tree view and list view controls used to access files and directories on the local file system. The following components are added to the Lazarus IDE component palette:

Misc Tab

- TShellTreeView
- TShellListView

Indicates which objects should be visible in a Shell control.

TObjectType is an enumerated type with values that indicate which file system objects are visible in a Shell control. Values from the enumeration are stored in the TObjectTypes set type.

Indicates that folders (directories) should be visible. This includes folders which represent virtual objects such as disk devices. Hidden folders are shown only if otHidden is also present.
Indicates that non-folder objects should be shown, which are usually files. Hidden files will be shown if otHidden is also present.
Indicates that hidden objects should be shown. This value is meaningful when used along with one of the other values.
Set type with values that indicate the visible objects in a Shell control.
Represents sorting options for the items in a shell control.

TFileSortType is an enumerated type with values that control the sort order for the items in a shell control. TFileSortType is the type used to implement the TCustomShellTreeView.FileSortType property.

No special sorting is done; items will appear in the order provided by the file system.
Items are sorted alphabetically with folders and files mixed.
Items are sorted alphabetically with folders placed at the beginning of the list.
Represents case sensitivity options for file masks.

TMaskCaseSensitivity is an enumeration type with values that represent case sensitivity options for the platform or OS where shell controls are implemented. TMaskCaseSensitivity is the type used for the MaskCaseSensitivity property in TCustomShellListView. It is also passed as an argument to methods in TCustomShellTreeView.

File masks used the default for the platform or OS.
File masks are case insensitive.
File masks are case sensitive.
Specifies an event handler signalled when an item is added to a shell control.

TAddItemEvent specifies an event handler signalled when an item is added to a shell control. TAddItemEvent is the type used to implement the OnAddItem event handler in TCustomShellListView and TCustomShellTreeView.

Applications must implement and assign an object procedure using the signature for the event to respond to the notification. The Sender argument must be cast to the correct class type to access properties and method in the control. Set the value in the CanAdd variable parameter to False to prevent the item from being added in the calling procedure.

Object (control) generating the event notification.
Base path for the item added to the shell control.
Search record with information for the item added to the shell control.
True if the item can be added.
The base class for a tree view control used to display files, directories and other objects (such as devices) from the local file system.

TCustomShellTreeView is a TCustomTreeView descendant that defines the base class used to display files, directories, and other objects (such as devices) from the local file system. TCustomShellTreeView provides a hierarchical tree view for the file system objects, and is used to navigate between items in the control.

TCustomShellTreeView extends the ancestor class with properties, methods, and events needed to access, maintain, and navigate file system objects in the tree. Applications should not create instances of TCustomShellTreeView; use the TShellTreeView class instead.

TCustomTreeView
Gets the value for the Path property.
Value for the property.
Sets the value for the FileSortType property.
New value for the property.
Sets the value for the ObjectTypes property.
New value for the property.
Sets the value for the Path property.
New value for the property.
Sets the value for the Root property.
New value for the property.
Sets the value for the ShellListView property.
New value for the property.
Sets the value for the UseBuiltinIcons property.
New value for the property.
Performs actions needed to create a new tree node in the shell control.

DoCreateNodeClass is an overridden method used to perform actions needed to create a new tree node in the Items for the shell control. DoCreateNodeClass sets NewNodeClass to the TShellTreeNode class type used in TCustomShellTreeView. DoCreateNodeClass calls the inherited method using NewNodeClass as an argument.

Class reference used to create tree nodes in the shell control.
Performs actions needed when LCL component streaming has been completed.

Loaded is an overridden procedure used to perform actions needed when LCL component streaming has been completed. In TCustomShellTreeView, this includes calling the inherited method and setting the initial value for the root directory. If the initial root directory was assigned at design-time, PopulateWithBaseFiles is called to load files in the shell control.

Creates a new tree node for the shell control.

CreateNode is an overridden method used to create an new TTreeNode instance for the shell control. CreateNode calls the inherited method to create the class instance used as the return value for the method.

CreateNode ensures that the tree node is a TShellTreeNode class instance; the class type can be overridden in the OnCreateNodeClass event handler. If the new tree node is not derived from TShellTreeNode, an EShellCtrl exception is raised to indicate the invalid node type.

Raises an EShellCtrl exception if the new tree node is not derived from TShellTreeNode.
TTreeNodeClass TCustomTreeView.OnCreateNodeClass
New tree node created in the method.
Adds tree nodes for file system objects found starting at the specified node / path.

PopulateTreeNodeWithFiles is a Boolean function used to fill the Items property with the file system objects for a given tree node. ANode contains the initial tree node examined in the method. ANodePath contains the path on the local file system to the tree node in ANode. The return value is True if at least one node was added to Items in the method.

No actions are performed in the method at design-time, and the return value is set to False.

PopulateTreeNodeWithFiles fills a list with TFileItem instances for file system objects matching the ObjectTypes for the shell control. DoAddItem is called for each TFileItem instance, which signals the OnAddItem event handler (when assigned). The event handler is used to selectively filter file system objects added to the Items in the control. If the TAddItemEvent handler sets its CanAdd argument to False, the file system object is not added to Items.

On exit, Items contains the TShellTreeNode instances where ANode is the parent. If an entry is a directory which has sub-directories, its HasChildren property is set to True.

PopulateTreeNodeWithFiles is used in the implementation of the PopulateWithBaseFiles and CanExpand methods in TCustomShellTreeView.

Returns True if at least one item was added to the shell control.
Initial tree node used when filling the Items for the shell control.
Path to the initial tree node used in the method.
Performs actions needed when a new item is selected in the shell control.

DoSelectionChanged is an overridden method used to perform actions needed when a new item is selected in the shell control. DoSelectionChanged calls the inherited DoSelectionChanged method, and ensures that a TCustomShellListView control assigned to ShellListView is synchronized to the current selection in the class.

No actions are performed in the method if values for either ShellListView or Selected have not been assigned (contain Nil).

Selected contains the current tree node selected in the shell control, and is used to determine if the selection is a file, directory, or other device. When it is a directory, its path is assigned to the Root property in ShellListView.

If Selected does not represent a directory, the path refers to a file name that must exist on the local file system. An EShellCtrl exception is raised if the selected item does not exist. If Selected has a parent tree node, its path is assigned to the Root property in ShellListView. If no parent is available, the Root property in ShellListView is set to an empty string ('').

Raises an EShellCtrl exception if Selected refers to a file name that no longer exists on the local file system.
TCustomTreeView.Selected
Performs actions needed to add a new tree node to the shell control.

DoAddItem is a procedure used to perform actions needed when a new tree node is added to the shell control. DoAddItem signals the OnAddItem event handler (when assigned) to examine and process the arguments passed to the method.

ABasePath contains the path on the local file system where the file system object exists.

AFileInfo is a TSearchRec instance with the details for the file system object.

CanAdd is a variable Boolean parameter used to indicate if the new tree node can be added to the shell control.

No actions are performed in the method when OnAddItem has not been assigned (contains Nil). Applications must implement and assign an object procedure to the event handler which responds to the event notification.

Base path for the new tree node.
TSearchRec with information about the file system object.
Indicates if the tree node can be added for the specified path.
Determines if the specified tree node can be expanded in the shell control.

CanExpand is an overridden Boolean function used to determine if the specified tree node can be expanded in the shell control. Node contains the TTreeNode examined in the method.

CanExpand calls the inherited method to signal the OnExpanding event handler (when assigned). No additional actions are performed if the inherited method returns False.

CanExpand temporarily disables the AutoExpand functionality in the shell control, and removes all child tree nodes in Node. The child nodes are re-created using the PopulateTreeNodeWithFiles method. This ensures that the shell control reflects the current content in the local file system during execution of the method. The value in AutoExpand is restored to its original value prior to exiting from the method.

The entire update process is done in a BeginUpdate / EndUpdate block to reduce the number of screen refreshes in the method.

TCustomTreeView.AutoExpand
True when the tree node contains child nodes and be expanded.
Tree node examined in the method.
Draws the Shell Icon for the specified tree node.

DrawBuiltInIcon is an overridden TSize function used draw an icon in the tree using the Shell icon for the file name in ANode. It re-implements the method in the TCustomTreeView ancestor, and does not call the inherited method.

When UseBuiltinIcons is True, the internal GetShellIcon routine is called to get the icon used for the file. The icon is drawn on the control Canvas using the rectangle in ARect. The icon is centered vertically in the specified rectangle.

The return value contains the dimensions for the icon as a TSize instance. When UseBuiltinIcons is False, the return value always contains a TSize instance with both the Width (CX) and Height (CY) are set to 0 (zero).

DrawBuiltInIcon is defined for the Windows platform only; it requires use of the SHGetFileInfoW routine in the FPC ShellApi.pp unit.
TCustomTreeView.DrawBuiltinIcon
TSize instance with the dimension for the icon.
Tree node with the name for the file system entry.
Rectangle where the icon is drawn.
Gets the size for a shell icon used in the control.

GetBuiltinIconSize is an overridden TSize function used to get the dimensions for a shell icon displayed for a file system entry in the control. GetBuiltinIconSize re-implements the method from the TCustomTreeView ancestor, and does not call the inherited method.

The return value is a TSize instance with the Width (CX) and Height (CY) for the shell icon.

When UseBuiltinIcons is True, the internal member used for the icon size is checked. It is used when explicit values have been set for the Width and Height in the TSize instance. If the default values (0) are in Width and Height, the internal GetShellIcon routine is called to get the icon size used for Drive letter designations. It is assigned as the return value for the method, and stored in the internal member.

When UseBuiltinIcons is False, the return value always contains a TSize instance with both the Width (CX) and Height (CY) are set to 0 (zero).

GetBuiltinIconSize is defined for the Windows platform only; it requires use of the SHGetFileInfoW routine in the FPC ShellApi.pp unit.
TCustomTreeView.GetBuiltinIconSize
TSize instance with the dimensions for the shell icon.
Constructor for the class instance.

Create is the constructor for the class instance. Create calls the inherited method using the value in AOwner as the owner for the class instance. Create initializes an internal member used to monitor the Root property for changes to its value. Create sets the value in ObjectTypes to display folders.

Please note: Design-time values in the Items property are populated when the Loaded method is called during component streaming.

Component that owns the class instance.
Destructor for the class instance.

Destroy is the destructor for the class instance. Destroy ensures that the ShellListView is set to Nil prior to calling the inherited destructor.

Returns the initial path in the file system hierarchy for the platform.

GetBasePath is a String class function used to get the notation for the initial path in the file system hierarchy. The return value contains the following values for the supported platforms:

Windows platforms (other than Windows CE)
  '' (empty string)
Windows CE
  '\'
UNIX-like operating systems
  '/'
Amiga
  '' (empty string)

Returns the effective root value, returning the value of GetBasePath() of Root is empty or the Root property value otherwise.
Returns the path (including the file name) from the file system that a particular node represents.
Fills the tree view when the Root directory is empty.
The implementation of PopulateWithBaseFiles is platform-specific.

For Windows platforms other than Windows CE, the tree view is filled with TShellTreeNode entries for the logical drive names found on the system. The drive information is retrieved using the GetLogicalDriveStrings routine in the Windows API.

For other platforms, which do not use drive letters, the tree view is populated with nodes for the files or directories in the base path for the control.

PopulateWithBaseFiles is called from the Loaded, SetRoot, and SetFileSortType methods when an empty string ('') is assigned to the Root property.

No actions are performed in the method at design-time, or when the component is loaded using the LCL streaming mechanism on platforms other than Windows.

Updates the tree view to display file system objects starting at the specified tree node.
Used in the implementation of the SetObjectTypes method.
Tree node with the initial path displayed in the shell control; Nil defaults to the root directory.
Indicates if OS-provided icons are used for entries in the Shell control.

UseBuiltinIcons is a Boolean property which indicates if OS-provided icons are used for the file system entries in the Shell control.

The default value for the property is True. Setting a new value for the property causes the Invalidate method to be called to redraw the control.

UseBuiltinIcons is used in the DrawBuiltinIcon method, and controls whether the corresponding method is called in the widgetset class. When UseBuiltinIcons is set to False, an icon is not drawn in the DrawBuiltinIcon method.

Indicates which objects should be shown in this control (for example if it should show files and directories or only directories).
Connects this ShellTreeView to a ShellListView.

ShellListView is a TCustomShellListView property used to connect the tree view to a list view control.

Methods and properties in the list view control can be used to change the currently selected directory, or to limit its display to specic object types. Changes to the Root or ObjectTypes properties in the list view are propogated to the associated tree view control.

In a similar fashion, changes to the Root property or the selected item in the tree view causes the changes to be propogated to the associated list view control.

Indicates how the items should be sorted in the tree.

FileSortType is a TFileSortType property used to indicate the sort order for tree nodes in the Items property. See TFileSortType for information about enumeration values and their meanings.

Changing the value in FileSortType causes the Items property to be cleared, and the tree nodes to be re-created for the Path when Root has been assigned. If Root contains an empty string (''), the PopulateWithBaseFiles method is called. Otherwise, the Path is updated to force the control to be reloaded.

No action other than setting the property value is performed in the method at design-time.

The value in FileSortType is used in the PopulateTreeNodeWithFiles method and passed as an argument to the internal GetFilesInDir procedure.

The value in FileSortType is not used in PopulateWithBaseFiles on Windows platforms. The entries are logical drive letters, and are processed in the order provided by the file system.
Indicates the directory to start showing the list of items.

Root is a String property used to set the directory (or logical device) used to fill the list of items in the tree view control. Changing the value in Root causes the Items in the control to be re-populated.

No actions are performed in the method when a new value is set for the the Root property while the component is being loaded using the LCL streaming mechanism. The actions are performed when the Loaded method is called.

An empty string ('') indicates that the base path for the platform should be used to populate the tree view. This causes the PopulateWithBaseFiles method to be called to determine the Items displayed in the control.

Setting Root to an invalid path name causes an EInvalidPath exception to be raised at run-time. The error is ignored, and an exception is not raised, at design-time to prevent crashing the Lazarus IDE.

TShellTreeNode instances are created and added to the Items property using the expanded fully qualified path name in Root.

If ShellListView has been assigned for the control, its Root property is updated to match the new value for the property.

Path to the directory displayed in the shell control.

Path is a String property which represents the path on the local file system to the Selected tree node in the control.

Reading the value for the property calls the GetPathFromNode method to derive the value for the property using the Selected tree node. The full path for the TShellTreeNode is used, with a path delimiter appended for a directory entry. If the path is not absolute, the base path name is prepended to the path value.

Setting the value for the property causes the the new value to be resolved to a fully qualified path name when needed. A relative path is expanded into a fully qualified absolute path value resolved relative to the base path in Root.

An EInvalidPath exception is raised when setting Path to a value that is not valid, including:

- The path does not exist on the local file system
- The path cannot be resolved as a directory located under the Root directory
- The path represents an entry not valid for the settings in ObjectTypes

Event handler signalled when an item (tree node) is added to the shell control.

OnAddItem is a TAddItemEvent property which contains the event handler signalled when an item (tree node) is added to the shell control. OnAddItem is signalled from the PopulateTreeNodeWithFiles method, and allows the base path and file information for each file to be checked before it is added to the tree view.

Implements a tree view control to display the files, directories and other objects (such as devices) from the local file system.

TShellTreeView is a TCustomShellTreeView descendant that implements a tree view used to display files, directories, and other objects (such as devices) from the local file system. TShellTreeView provides a hierarchical tree view for the file system objects, and is used to navigate between items in the control.

TShellTreeView sets the visibility for properties, methods, and events defined in the ancestor class.

Uses the Color from the Parent control, when enabled.

ParentColor determines if the control should use the Color from the Parent control, when enabled. The default value for the property is False in TShellTreeView.

When this property is True, all changes to the Color of the parent will also be applied to the Color of the control, ensuring that they both contain same value. If the Color of the control is changed by the application, then ParentColor will be automatically set to False.

Enables navigation using the Tab key.

The default value for the properly is True in TShellTreeView.

TWinControl.TabStop
Tag value for the component.

Tag can be used to store an integer value in the component. This value is streamed together with all other published properties. It can be used for instance to quickly identify a component in an event handler.

TComponent
Specifies an event handler signalled when an item is added to TCustomShellListView.

TCSLVFileAddedEvent specifies the interface for an event handler signalled when a TListItem instance is added to TCustomShellListView. TCSLVFileAddedEvent is the type used to implement the OnAddItem property in TCustomShellListView.

Applications must implement and assign an object procedure using the event signature to respond to the notification. Sender must be cast to the correct class type to access properties and methods in the control for the notification. Or, use the ListView property in the Item argument.

TListItem
Object (control) generating the event notification.
List item for the event notification.
The base class that defines a list view control to display the files, directories and other objects (such as devices) from the local file system.

TCustomShellListView is a TCustomListView descendant which defines a list view control for file system objects on the local file system. TCustomShellListView extends the ancestor class with properties, methods, and events needed to access and maintain items in the control including:

- Mask
- MaskCaseSensitivity
- ObjectTypes
- Root
- ShellTreeView
- Items
- GetPathFromItem
- OnAddItem
- OnFileAdded

Application should not create instance of TCustomShellListView; use the TShellListView descendant which sets the scope for members in the class.

Sets the value for the Mask property.
New value for the property.
Sets the value for the MaskCaseSensitivity property.
New value for the property.
Sets the value for the ShellTreeView property.
New value for the property.
Sets the value for the Root property.

Calls Clear to remove list items in the control. Calls PopulateWithRoot to load file system entries in the new root directory. Raises an EInvalidPath exception at run-time if Value contains an invalid path name. Does not raise an exception at design-time to prevent crashing the IDE.

Raises an EInvalidPath exception at run-time if Value contains an invalid path name.
New value for the property.
Registers an association between the class type and its widgetset class.

WSRegisterClass is an overridden class method in TCustomShellListView. It registers properties that are ignored in the class instance during LCL component streaming, including:

- ItemIndex (Used in older LCL versions)
- BevelKind (Provided for Delphi compatibility)
- TListItem.OverlayIndex (Provided for Delphi compatibility)

It calls the inherited method, and registers the companion widgetset class instance.

TWinControl.WSRegisterClass
Fills the list view with file system information for the root directory.

PopulateWithRoot is a procedure used to fill the Items in the list view with file system entries for the Root directory.

No actions are performed in the method at design-time, or when Root contains an empty string ('').

PopulateWithRoot calls the internal GetFilesInDir helper to get a list of file system items for the path which match the Mask and ObjectTypes specified for the control. Each of the files in the list are passed to DoAddItem / OnAddItem to determine if they can be added to the Items in the control.

A TListItem instance is added to Items to represent the files or directories. The Data property in the list item is used to store a pointer to the file size. Values are added to SubItems with the string representation for the file size, and the file extension.

When UseBuiltInIcons is set to True, the GetBuiltInImageIndex method is called to get the ImageIndex for the built-in icon for a list item. This action is performed using the path to the current file name when LargeImages and/or SmallImages have not been assigned. The value in ViewStyle determines the image size requested. When ViewStyle is vsIcon, LargeImages is checked (when assigned). Otherwise, SmalImages is checked (when assigned). If an imagelist exists in either LargeImages or SmallImages, the existing ImageIndex in the list item is used.

The OnFileAdded event handler is signalled (when assigned) for each new entry added to Items.

The Sort method is called prior to exit to order the Items in the control using the option specified in the FileSortType property.

Updates the size for Columns in the list view.

Resize is a method used to update the size for Columns defined in the list view control. Resize calls the inherited method to capture the internal Width and ClientWidth for the control, and to signal the OnResize event handler (when assigned).

Resize checks the Columns defined for the control. No additional actions are performed in the method if fewer than 3 (three) columns are defined for the control. This is the number of columns defined in the constructor for the vsReport ViewStyle.

No additional actions are performed if AutoSizeColumns is set to False and an explicit width has been assigned for the first column in the list view control.

When AutoSizeColumns is set to True, Resize adjusts the width for the columns so that they fill the display area for the control without the need for a horizontal scroll bar. The value in ClientWidth is used to determine the available space for the columns. The first column (Name) uses a larger percentage of the available display area (50% when the control width is less than 400 pixels, 70% for a larger control width). The remaining columns (Size and Type) get equal portions of the remaining display area.

Set AutoSizeColumns to False use the widths explicitly assigned to entries in the Columns property.

Resize is used called from the Create constructor, when the bounds for the control are updated in the ChangeBounds method. It is also called when AutoSizing is enabled for the control, and when a new value is assigned to the Width property.

TCustomListView.ViewStyle TCustomListView.Columns TListColumns TViewStyle TControl.Width
Sets the value for the AutoSizeColumns property.
New value for the AutoSizeColumns property.
Signals the OnAddItem event handler when an entry is added to the Items in the control.
Base path for the list view.
TSearchRec with the information for the new entry.
Set the argument to True to allow the item to be added; set to False to prevent adding the item.
Gets the index position for the built-in icon used for the specified path or file name.

GetBuiltinImageIndex is an Integer function used to get the image index for a built-in icon provided by the operating system or platform.

The return value contains the ordinal position for the image used for the file name or path specified in AFilename. The return value is -1 if an image could not be selected for the value in AFileName.

When ALargeImage is True, the index value refers to a large image as used in the vsIcon view style. When set to False, it refers to a small image as used in the other view styles.

GetBuiltinImageIndex calls the GetBuiltInImageIndex method in the widgetset class to get the return value for the method. The widgetset class handles storing the built-in image to the correct image list when the handle for the image list has not already been assigned.

GetBuiltinImageIndex is called from the PopulateWithRoot method when UseBuiltInIcons is set to True.

In the current LCL version, GetBuiltinImageIndex is implemented for the Windows platform only.
TCustomListView.LargeImages TCustomListView.SmallImages
Ordinal position for the built-in image.
File name or path used to find the associated image.
True if the large image list is used for the image.
Event handler signalled when a file is added to the Items in the control.

OnFileAdded is a TCSLVFileAddedEvent property representing the event handler signalled when a file is added to the Items in the control. Applications must implement and assign an object procedure to the event handler to respond to the event notification. See for information about the arguments passed to the event handler.

OnFileAdded is signalled (when assigned) from the PopulateWithRoot method after calling DoAddItem and OnAddItem, and after the list item has been added to the Items property.

Constructor for the class instance.

Create is the overridden constructor for the class instance. Create calls the inherited method using AOwner as the owner of the class instance. Create sets the default values for properties in the class instance, including:

UseBuiltInIcons
  True
ViewStyle
  vsReport view style
ObjectTypes
  [otNonFolders]
MaskCaseSensitivity
  mcsPlatformDefault
Columns
  Creates three columns for File Name, File Size, and File Type

Create calls the Resize method to adjust the widths for the Columns defined in the method.

TCustomListView.ViewStyle TCustomListView.Columns
Owner for the class instance.
Destructor for the class instance.

Destroy is the overridden destructor for the class instance. Destroy ensures that a control assigned to the ShellTreeView property is set to Nil. Destroy calls the inherited method.

Gets the path on the local file system for the specified item.

GetPathFromItem is a String function used to get the path on the local file system for the list item specified in ANode. The return value contains the content from the Root property with a trailing path delimiter, joined with the Caption for the TListItem in ANode.

TListItem
Complete path to the item.
List item examined in the method.
Indicates if columns in the control are automatically resized to fill the client display area.

AutoSizeColumns is a Boolean property which indicates if the Columns for the control are automatically resized to fill the client display area for the control. When set to True, the widths for the Columns are adjusted so that they fill the client display area without the need for a horizontal scroll bar. The default value for the property is True.

Changing the value for the property to True causes the Resize method to be called.

The Resize method will be called at least once, even when AutoSizeColumns is set to False, if an explicit width has not been set for the first column in the control.
TCustomListView.Columns TListColumn
File mask used to select items displayed in the shell control.

Mask is a String property used to supply a mask which determines the file system objects displayed in the shell control. Mask can contain one or more mask values delimited by the Semicolon (';') character. For example:

*.exe; br*.com; c??.*

Changing the value in Mask causes the Clear method to be called for the shell control. In addition, the Items property calls its Clear method to remove entries stored in the property. The PopulateWithRoot method is called to re-populate the shell control using the new mask value.

The value in Mask is passed as an argument to the internal GetFilesInDir helper which gets the file system objects displayed in the List View control.

Use MaskCaseSensitivity to specify the case sensitivity option used when matching file masks in the shell control.

TCustomListView.Clear
Case Sensitivity option enabled for file masks in the shell control.

MaskCaseSensitivity is a TMaskCaseSensitivity property which represents the case sensitivity option used for file masks in the shell control. The default value for the property is mcsPlatformDefault. See TMaskCaseSensitivity for a description of the enumeration values and their meanings.

Changing the value in MaskCaseSensitivity causes the shell control to re-populate its file Items using the Mask for the control.

Indicates which objects are visible in the control (files and/or directories, hidden files, etc.).
Indicates the initial directory path whose objects are displayed in the control.

The most important property of the ShellListView, indicates the directory whose contents will be shown. This property is automatically managed if the property ShellTreeView is filled. If this property is empty, nothing will be shown.

Used to connect the ShellListView to a ShellTreeView.

ShellTreeView is a TCustomShellTreeView property used to connect the list view control to a shell tree view control. ShellTreeView provides access to the currently selected device, file, or directory in the local file system.

Changing the value in ShellTreeView causes the Clear method to be called to refresh the list view control. The path to the Selected item in the tree view is used as the Root property in the list view. The PopulateWithRoot method is called to fill the Items in the list view control.

TCustomTreeView.Selected TCustomListView.Clear
Indicates if icons provided by the OS or platform are used for items in the list.

UseBuiltInIcons is a Boolean property which indicates if icons provided by the OS or platform are used for the Items in the list view control. The default value for the property is True.

UseBuiltInIcons is used when the list view control is populated with the names for the file and/or directories on the local file system. When set to True, the GetBuiltInImageIndex method is called to get the image index for a TListItem stored in the Items property.

Set UseBuiltInIcons to False to use custom images provided in the LargeImages or SmallImages properties.

UseBuiltInIcons and GetBuiltInImageIndex require support in the widgetset class to use system-provided icons. This support is currently implemented for the Windows platform only.
TCustomListView.LargeImages TCustomListView.SmallImages
Event handler signalled to determine if the specified file information can be added to the Items for the list view.

OnAddItem is a TAddItemEvent property used to implement the event handler. It is signalled to determine if the specified file can be added to the Items for the list view.

Arguments passed to the event handler identify the base path and file information examined in the procedure. Use the CanAdd argument to indicate if the file information can be added in a calling routine. See for more information about the event handler definition.

OnAddItem is signalled from the DoAddItem method (when assigned).

Implements a list view control to display the files, directories and other objects (such as devices) on the local file system.

TShellListView is a TCustomShellListView descendant which implements a list view control for file system objects on the local file system. TShellListView contains properties, methods, and events needed to access and maintain items in the control including:

- Mask
- MaskCaseSensitivity
- ObjectTypes
- Root
- ShellTreeView
- Items
- GetPathFromItem
- OnAddItem
- OnFileAdded

The background color for the control.

The default value for the properly is clWindow in TShellListView.

If Color is set to clDefault, it needs to be passed through GetDefaultColor to resolve clDefault to a TColor value. Convenience routines which obtain the color by resolving clDefault and ParentColor are also provided as TControl.GetColorResolvingParent and TControl.GetRGBColorResolvingParent.

TControl.Color
Uses the Color from the Parent control, when enabled.

ParentColor determines if the control should use the Color from the Parent control, when enabled. The default value for the property is False in TShellListView.

When this property is True, all changes to the Color of the parent will also be applied to the Color of the control, ensuring that they both contain same value. If the Color of the control is changed by the application, then ParentColor will be automatically set to False.

Using ParentColor when the Color value is clDefault can cause problems in resolving the actual color value. To obtain the Color property of a control while taking into account clDefault and ParentColor, use the GetColorResolvingParent method. This method might return a non-RGB color, but will never return clDefault. To obtain a purely RGB result use the GetRGBColorResolvingParent method.

TControl.ParentColor
Represents tree nodes in TShellTreeView.

TShellTreeNode is a TTreeNode descendant which represents tree nodes in TShellTreeView. TShellTreeNode extends the ancestor class with properties and methods needed to work with files or directories on the local file system. TShellTreeNode is the class type reference used to create new nodes in the TCustomShellTreeView.CreateNode method.

Sets the value in the BasePath property.
New value for the property.
Gets the short file name for the item represented in the tree node.

ShortFilename is a String function used to get the short file name for the item represented in the tree node. ShortFilename tries to get the file name from an internal TSearchRec for the tree node. If the file name is an empty string (''), the name in the search record is used as the return value. ShortFilename does not include path information in the return value.

Use FullFilename to get a complete file name which includes path information for the item represented in the tree node.

Short file name for the item represented in the tree node.
Gets the full file name including path for the item represented in the tree node.

FullFilename is a String function used to get the full path and name for the file system object represented by the tree node. FullFilename includes the value in BasePath when it is available, and the name from the TSearchRec for the tree node. For directory and/or device nodes, the return value does not include a trailing path delimiter. On Windows platforms (other than WinCE), device identifiers (like 'C:') are modified to include a trailing path delimiter ('C:\').

Use ShortFilename to get the name for the tree node without path information.

The full path and name for the file system object.
Indicates if the tree node is a directory on the local file system.

IsDirectory is a Boolean function which indicates if the file system object for the the tree node is a directory on the local file system. The return value is True when the file attributes in the TSearchRec for the tree node includes the faDirectory attribute.

Use HasChildren to determine if the shell tree node has child nodes representing sub-directories.

TTreeNode.HasChildren
True when the tree node represents a directory on the local file system.
Contains the path to the file system object in the tree node.

BasePath is a read-only String property which contains the path on the local file system to the object in the tree node. The value for the property is set when the tree node is created in TShellTreeView methods using the SetBasePath method in the class instance.

Exception raised for errors occurring in shell controls.
EShellCtrl
is a Exception descendant raised when errors occur in shell controls.
Exception raised for an invalid path in shell controls.
EInvalidPath
is a EShellCtrl descendant raised for an invalid path in shell controls.
Provides strings values with details about classes used in shell controls for the debugger.

DbgS is an overloaded String function used to get a string value with details about classes used in shell controls. The value is intended for use in the debugger. The overloaded variants provide support for the TObjectTypes and TMaskCaseSensitivity class types.

For TObjectTypes, a string is built to represents the set type using the format:

[otFolders,otNonFolders,otHidden]

For TMaskCaseSensitivity, a string version of the enumeration value is used as the return value. For example:

'mcsPlatformDefault' 'mcsCaseInsensitive' 'mcsCaseSensitive'
Formatted values for the debugger.
TObjectTypes examined in the routine.
TMaskCaseSensitivity examined in the routine.
Registers components for use in the Lazarus IDE.

The following components are added to the Lazarus IDE component palette:

Misc Tab

- TShellTreeView
- TShellListView