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 End-User Documentation
View this topic on docs.devexpress.com (Learn more)

Restrictions and Protection

This topic describes how to prevent end users from document modification. The Rich Text Editor provides three ways to solve this task: protect the entire document from editing, restrict certain operations and prevent users from inserting unnecessary elements.

Expanded Restrict Document Modification

You can restrict document modification using the Document.Protect method. This method sets the password, and specifies actions allowed for the protected document (the DocumentProtectionType enumeration values). The Document.IsDocumentProtected property indicates whether content modification protection is enabled.

Use the Document.Unprotect method to disable protection. Note that it unlocks the document without a password request. To prompt the user to enter a password, execute the UnprotectDocumentCommand command.

Note

The protection mechanism described above affects only the document modification.

Expanded Open and Save Password-Encrypted Files

The DXRichEdit allows you to load and save password-encrypted files.

Open an Encrypted File

Specify the DXRichEditDocumentImportOptions.EncryptionPassword property to decrypt a loaded file. The table below lists a chain of events raised if the EncryptionPassword property is not specified or returns an invalid password.

Event Description
RichEditControl.EncryptedFilePasswordRequested Fires if the EncryptionPassword property is not specified or returns an invalid password. Use the EncryptedFilePasswordRequestedEventArgs.Password property to specify a new password.
RichEditControl.EncryptedFilePasswordCheckFailed Occurs if the EncryptedFilePasswordRequestedEventArgs.Password is set to an empty or invalid password. Handle this event to obtain the error that led to this event (EncryptedFilePasswordCheckFailedEventArgs.Error) and determine whether to prompt a user for a password (EncryptedFilePasswordCheckFailedEventArgs.TryAgain).
RichEditControl.DecryptionFailed Raised if the TryAgain property is not specified or set to false. This event also occurs if the RichEditControl fails to open an encrypted file. The DecryptionFailedEventArgs.Exception property indicates the exception that led to this event.

The code sample below shows how to handle the events mentioned above to prompt users to enter a password. If the user cancels the operation or exceeded the amount of attempts to enter the password, the RichEditControl loads an empty file.

Note

A complete code sample project is available at Document Encryption (Simple Example) repository on GitHub.

The RichEditControl.EncryptedFileIntegrityCheckFailed event occurs if the document did not pass the code verification.

Important

If an encrypted file is loaded using the RichEditControl.DocumentSource property, its format cannot be detected. Use the RichEditDocumentSource instance to bind encrypted files.

Encrypt a Document with a Password

Use the Document.Encryption property to access the document encryption options.

Call the RichEditControl.SaveDocument(String, DocumentFormat, EncryptionSettings) (see RichEditControl.SaveDocument) method overload to password-protect the document on save. Use the EncryptionSettings object properties to specify password and protection type.

Expanded Grant Permission to Users

Create Range Permissions as described in the steps below to allow certain users to edit parts of a protected document.

  1. Set the users and user group lists. The default users list is empty and the user group list contains predefined entries (Everyone, Administrators, Contributors, Owners, Editors and Current User). To use a custom list of users or user groups, provide a custom service implementing the IUserListService or IUserGroupListService interface and register this service with the DevExpress.XtraRichEdit.RichEditControl.ReplaceService``1 method. The RichEditControl does not associate users with groups, so user names and group names are independent.

  2. The edit permission is given depending on the authentication credentials. To define the identity of the current user, use the AuthenticationOptions class properties.

  3. Call the SubDocument.BeginUpdateRangePermissions method to access the document range permissions collection.
  4. Create a new RangePermission object using the RangePermissionCollection.CreateRangePermission method.
  5. Utilize the RangePermission.UserName and/or RangePermission.Group properties to specify the specific user and/or the group of users that are eligible to edit the document.

    The table below shows what properties should have the same value to make the range editable to the current user.

    This property value

    Should be equal to

    DXRichEditAuthenticationOptions.Group

    RangePermission.Group

    "Everyone"

    DXRichEditAuthenticationOptions.UserName

    DXRichEditAuthenticationOptions.EMail

    RangePermission.UserName

  6. Add the created object to the corresponding collection.
  7. Finalize the modification with the SubDocument.EndUpdateRangePermissions method.
  8. Enable document protection as described above.

  9. Customize the appearance of the protected ranges in the document. At runtime, they are highlighted with a certain color and enclosed with bookmark brackets. By default, the highlighting color is selected from a predefined colors collection. This is done to specify different highlighting colors for ranges that belong to different user groups. There is no straightforward way to change these colors manually.

    You can set the highlighting options to the ranges that are editable to the current user only. To do that, use the RangePermissionOptions properties. They can be accessed through the Options.RangePermissions notation.

Expanded Restrict Performing Operations

Protect the document from editing, copying or printing by restricting the corresponding functions. To perform the restriction, access the desired operation using the RichEditControl.BehaviorOptions property and specify its behavior. Depending on the selected property value, the application menu buttons that correspond to restricted operations can be disabled or hidden. Additionally, you can prevent the showing of the context menu. To do that, use the DXRichEditBehaviorOptions.ShowPopupMenu property.

The code execution result is illustrated in the picture below. Print, Quick Print and Print Preview are disabled, the Copy item is hidden from the context menu.

Expanded Restrict Using Document Elements

You can also forbid the formatting of characters and paragraphs or the use of certain document elements, such as pictures, tables, fields, etc.

These restrictions can be specified by the RichEditControl.DocumentCapabilitiesOptions property, as illustrated in the following code sample.

The application menu items that correlate with the forbidden actions can be hidden or disabled. If a document is loaded after certain restrictions are applied, the corresponding settings are set to default and the restricted objects are not created. The existing floating pictures are converted into inline pictures, the text boxes and their contents are hidden.

Expanded See Also

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