Net Edition

Folderbrowserdialog Unmasked: Everything You Wanted to Know About the Folder Browser Component From .net Framework

Original Article :http://www.ssware.com/articles/folderbrowserdialog-unmasked-everything-you-wanted-to-know-about-the-folder-browser-component-from-dotnet-framework.htm

Introduction

The FolderBrowserDialog, available as part of the .Net framework, provides a folder browser component for your C# and VB.Net applications. The UI consists of a modal dialog which contains a tree control displaying all the files and folders on the system. The user can then browse and select a folder from the tree. The full path of the selected folder is then returned.

Basic Usage

To display a folder explorer UI to the user, a FolderBrowserDialog instance is created and the ShowDialog method is called. This shows the modal dialog containing the folder browser control (tree) and an OK and Cancel button. If the user selects a folder and clicks the OK button, the ShowDialog method returns DialogResult.OK and the SelectedPath property contains the full path of the selected folder. If the user clicks the Cancel button, the ShowDialog method returns DialogResult.Cancel.

Advanced Usage

The FolderBrowserDialog has some additional features such as limiting the view of the file system that is displayed to the user, pre-selecting a folder when the dialog is first displayed and displaying a button to allow the user to create a new folder.

The RootFolder property can be set to the full path of the folder which is to be displayed as the root of the tree control of the folder browser component. For example, if this property is set to Environment.SpecialFolder.Personal, only folders from the 'My Documents' are displayed in the tree, so the user can only select 'My Documents' or its sub-folders.

Prior to displaying the folder browser control, the SelectedPath property can be set to the full path of a folder causing that folder to be pre-selected in the folder browser tree. For example, when this property is set to "c:", the node corresponding to the c: drive is pre-selected in the tree when the dialog is first displayed.

If the ShowNewFolderButton property is set to true, then, in addition to the folder browser tree control, and the OK and Cancel buttons, the folder browser dialog also displays an additional 'New Folder' button which when clicked, creates a new folder under the currently selected folder.

Limitations

While the folder browser component is a handy way to allow the users to browse and select folders, it suffers from many limitations, some of them preventing the component from being of practical use in applications.

Modal Functionality

The most visible drawback of the folder browser component is that it displays its UI in the form of a modal dialog. When shown, it blocks the rest of the application until the user has chosen a folder. As long as the dialog is displayed, no input (keyboard or mouse click) can occur except within the dialog box. The user must click the OK or Cancel button before input to the calling program can occur.

This is a very annoying and limiting feature of the FolderBrowserDialog. Users are very likely to be irritated and annoyed when they have to interact with a modal dialog every time they have to explore and select a folder. A non-modal UI control which can be put inside of one of the applications's own forms or dialogs is a much more user-friendly way of displaying the same UI.

No Virtual (Non-file system) folders

The FolderBrowserDialog does not allow the user to select virtual (Non-file system) folders such as the Control Panel or My Computer. It only allows the user to select a file system path such as "c:" or "c:windows".

No Files

The component does not allow the user to select files. This is a major drawback since there are many circumstances where the user may need to select a file while still using the tree UI to browse to that file.

Limited Choice of RootFolder

The root folder of the folder browser control can be only set to one of the 'special folders' defined by Windows such as the 'My Documents' or 'My Computer'. This is a major limitation since this means you cannot set the root folder to a path such as the "d:" drive.

No Check Boxes

The folder explorer tree in the FolderBrowserDialog cannot show check boxes next to nodes. Ability to show multi-state check boxes can be a very handle feature for such a control.

No Filtering

The FolderBrowserDialog has no support for filtering. For example, it is not possible to display only network folders or only shared folders or only folders starting with the string "Documents" or files having a particular extension.

No Custom Controls

When using the FolderBrowserDialog, you are only limited to the actual folder explorer tree control, the OK, Cancel and New Folder buttons and the description label. It is not possible to add custom controls to the dialog box. This can be useful in many circumstances such as when you want to show a thumbnail/preview of the selected file/folder or any kind of additional information.

No Appearance Control

The appearance of the FolderBrowserDialog and its constituent controls cannot be changed. Neither can attributes of individual folders show in the folder explorer control be changed. For example, it is not possible to change the background color of the tree control or to set the font and color of individual nodes/folders in the tree.

No Custom items

The FolderBrowserDialog cannot display external/custom items in the folder explorer tree. For example, it may be necessary to display items from an FTP location in addition to the file system items. This is not possible with the FolderBrowserDialog.

No Lockdown

The FolderBrowserDialog allows unhindered operations on folders. The user can rename folders, do drag-drop operations and display the context menu and invoke various operations. In many cases, it may be necessary to limit or altogether prevent such potentially dangerous and irreversible operations, however the FolderBrowserDialog provides no way of doing that.

Beyond The FolderBrowserDialog : The FolderView Control

The FolderView Control brings a Windows Explorer like folder browser component to your applications complete with AutoUpdate, dragdrop, icons, contextmenus, Non-file system items, default key-handling, infotips and renaming. It features powerful behavior control and customization functionality that takes it miles ahead of Windows Explorer by adding features like filtering, checkboxes, custom items, multiple root nodes, dragdrop control and customization of default contextmenus, displaynames, icons and infotips.

The FolderView control is a UI control which can be dropped right inside your own forms and dialogs. A non-modal file & folder browsing/selection experience right inside your own dialogs and forms is something that users will appreciate and find intuitive and simple.

Additionally, FolderView overcomes all the limitations of the FolderBrowserDialog and provides far greater and advanced features and functionality than the FolderBrowserDialog. The following table is a quick comparison of the FolderView Control with the FolderBrowserDialog.

Drop-In Windows Explorer like folder browser functionality.
FolderView Control : Yes
FolderBrowserDialog : Modal UI. The component cannot be dropped in your own form.

• Complete Windows Explorer functionality include a file/folder browsing listview (similar to Windows Explorer's right-side) and a drive selection control (similar to Windows Explorer's address bar)
  FolderView Control : Yes. As part of Shell MegaPack
  FolderBrowserDialog : No

• Ability to select virtual (Non-file system) folders
  FolderView Control : Yes
  FolderBrowserDialog : No

• Ability to specify any and all folders as root.
  FolderView Control : Yes
  FolderBrowserDialog : No

• Ability to show files as well as folders.
  FolderView Control : Yes
  FolderBrowserDialog : No

• Multi-state check boxes
  FolderView Control : Yes
  FolderBrowserDialog : No

• Filtering capabilities
  FolderView Control : Yes
  FolderBrowserDialog : No

• Custom controls
  FolderView Control : Yes
  FolderBrowserDialog : No

• Appearance Control
  FolderView Control : Colors and appearance of the control as a whole and of individual folders/files can be changed.
  FolderBrowserDialog : No.

• Custom Items
  FolderView Control : Yes
  FolderBrowserDialog : No

• Prevent renaming, drag-drop, context menus
  FolderView Control : Yes. For all folders or on a per-folder basis.
  FolderBrowserDialog : No

• Multiple root folders
  FolderView Control : Yes
  FolderBrowserDialog : No

• Change default display names, icons, overlay icons, infotip, etc
  FolderView Control : Yes
  FolderBrowserDialog : No

• Simply and easy to use API
  FolderView Control : Yes
  Clumsy, inflexible API

• Access complete information of a file/folder including its displayname, fullpath, checkstate, selection state and attributes like whether it is a shortcut, shared, hidden, readonly, file and folder.
  FolderView Control : Yes
  FolderBrowserDialog : No

• Prevent display of contextmenus for all folders using a simple property or on a per-folder basis using an event.
  FolderView Control : Yes
  FolderBrowserDialog : No

• Prevent dragdrop for all folders using a simple property or on a per-folder basis using an event.
  FolderView Control : Yes
  FolderBrowserDialog : No

• Allow/disallow renaming for all folders using a simple property or on a per-folder basis using an event.
  FolderView Control : Yes
  FolderBrowserDialog : No

• Allow/disallow selection for all folders using a simple property or on a per-folder basis using an event.
  FolderView Control : Yes
  FolderBrowserDialog : No

• Allow/disallow expanding/collapsing on a per-folder basis using an event.
  FolderView Control : Yes
  FolderBrowserDialog : No

• Change default drag actions during dragdrop (e.g. from Copy To Move)
  FolderView Control : Yes
  FolderBrowserDialog : No

• Control checking/unchecking on a per-folder basis.
  FolderView Control : Yes
  FolderBrowserDialog : No

• Prevent execution of default shell commands ( e.g. Open, Cut, Properties, etc. in response to keystrokes or through the context menu) for all folders using a simple property or on a per-folder basis using an event.
  FolderView Control : Yes
  FolderBrowserDialog : No

• Show/hide hidden folders using a simple property.
  FolderView Control : Yes
  FolderBrowserDialog : No

• Show/hide virtual folders ( e.g. Control Panel ) using a simple property.
  FolderView Control : Yes
  FolderBrowserDialog : No

• Enumerate all folders shown in FolderView.
  FolderView Control : Yes
  FolderBrowserDialog : No

• Enumerate all folders according to folder hierarchy structure.
  FolderView Control : Yes
  FolderBrowserDialog : No

• Execute shell commands ( e.g. Cut, Delete, etc ) on folders.
  FolderView Control : Yes
  FolderBrowserDialog : No

• Associate developer defined data with each folder
  FolderView Control : Yes
  FolderBrowserDialog : No

The FolderView control (and Shell MegaPack ) is available in two editions :

.Net Edition : For use in .Net development using Windows Forms, WPF and ASP.Net

ActiveX Edition : For use in applications developed using Visual C++/MFC/ATL, Visual Basic 6, VBA (Access, Word, Excel, AutoCAD,etc), Borland Delphi and Borland Builder, and HTML/ASP pages.

About the Author

G Himangi is a Senior Software Developer at LogicNP Software (http://www.ssware.com) and is a member of LogicNP Software's component and controls development team.

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