Comments in Rich Text Documents
- 6 minutes to read
The RichEditControl allows you to add comments to documents. You can add, edit, and remove comments in code and from the UI.
Create Comments
Use the following API to attach a comment to a document range:
| Member | Description |
|---|---|
| Paragraph.Range | Retrieves the paragraph’s range. |
| SubDocument.FindAll | Finds all document ranges that contain the expression or text string. |
| SubDocument.Comments | Provides access to the document’s Comment collection. |
| CommentCollection.Create | Creates a new item in the CommentCollection. |
The code snippet below creates an empty comment associated with the following phrase: “an extensive problem in hardware and architecture is the construction of the emulation of checksums”.
// The target range is the specific phrase in the introduction's first paragraph
DocumentRange[] foundRanges = richEditControl.Document.FindAll("an extensive problem in hardware and architecture is the construction of the emulation of checksums", SearchOptions.None);
if (foundRanges.Length > 0)
{
// Create a new comment
Comment comment = richEditControl.Document.Comments.Create(foundRanges[0], "Johnson Alphonso D", new DateTime(2014, 4, 25));
}
Create Nested Comments
The code snippet below demonstrates how to create a nested comment. To do that, pass the parent content as the CommentCollection.Create method’s parameter.
Document document = richEditControl.Document;
if (document.Comments.Count > 0)
{
// Create a new comment nested to the second comment in the collection
Comment nestedComment = document.Comments.Create("Brian Zetc", DateTime.Now, document.Comments[1]);
// Add text to the newly created comment
SubDocument nestedCommentDocument = nestedComment.BeginUpdate();
DocumentRange textRange = nestedCommentDocument.InsertText(nestedCommentDocument.CreatePosition(0),
"Suffix trees are comprehensively reviewed in Wikipedia");
nestedComment.EndUpdate(nestedCommentDocument);
}
Edit Comments
Edit Comment Content
Use the API from the table below to edit the comment’s content.
| Member | Description |
|---|---|
| Comment.BeginUpdate | Opens the comment for modification. Use the returned SubDocument object to add and edit comment content. |
| SubDocument.InsertText | Inserts a text string into the specified position. |
| TableCollection.Create | Inserts a table into the specified position. |
| ShapeCollection.InsertPicture | Inserts a floating picture into the specified position. |
| DocumentImageCollection.Insert | Inserts an inline image into the specified position. |
| ShapeCollection.InsertTextBox | Inserts a text box into the specified position. |
| Comment.EndUpdate | Finalizes the comment update. |
The following code sample adds text to the empty comment:
Document document = richEditControl.Document;
int commentCount = document.Comments.Count;
if (commentCount > 0)
{
document.BeginUpdate();
// The target is the second last comment
Comment comment = document.Comments[document.Comments.Count - 1];
// Change the comment's name, author and creation date
comment.Name = "Reference";
comment.Date = DateTime.Now;
comment.Author = "Vicars Annie";
document.EndUpdate();
}
Edit Comment Attributes
Use the following members to change comment parameters (author, date, etc.):
| Member | Description |
|---|---|
| Comment.BeginUpdate | Opens the comment for editing. |
| Comment.Author | Specifies the comment’s author. |
| Comment.Date | Specifies the comment’s last modified date. |
| Comment.Name | Specifies the comment name. |
| Comment.EndUpdate | Finalizes the comment update. |
The code snippet below changes the comment’s name, date and author.
Document document = richEditControl.Document;
int commentCount = document.Comments.Count;
if (commentCount > 0)
{
// The target comment is the first one
Comment comment = document.Comments[0];
if (comment != null)
{
// Open the comment for modification
SubDocument commentDocument = comment.BeginUpdate();
// Add text to the comment range
commentDocument.InsertText(commentDocument.CreatePosition(0),
"J. Taylor, Enabling Voice - over - IP and RAID with sofa, in Proceedings of NOSSDAV, Oct. 1994.\r\n" +
@"R.Tarjan, S.Shenker, J.Gray, A.Einstein, Q.Thomas, and X.Sato, ""Deconstructing operating systems with flanchedripper"", in Proceedings of INFOCOM, Mar. 2000.");
//End the comment update
comment.EndUpdate(commentDocument);
}
}
The image below demonstrates the result of the code execution.
Delete Comments
To remove a comment from the document, use the CommentCollection.Remove method as shown in the code snippet below.
Document document = richEditControl.Document;
if (document.Comments.Count > 0)
{
// Remove the fourth document comment
document.Comments.Remove(document.Comments[3]);
}
Comments in the User Interface
Users can use the Review Ribbon tab to insert, modify or remove comments. Refer to the Lesson 5 - Create Separate Ribbon Pages for a Rich Text Editor topic for more information on how to add the ribbon menu to the application.
The Comment group on the Review tab allows users to insert new comments, remove existing comments and navigate through all the comments in the document.
The Tracking group buttons allow users to highlight comments in the document, to filter them by the author, and specify whether to display comments in the document margins or Reviewing Pane.
To provide the application with the Reviewing Pane, set the RichEditControl.ShowReviewingPane property to true in XAML.
<dxre:RichEditControl ShowReviewingPane="True"/>
Display Options
The comments are displayed in the Reviewing Pane or in balloons that appear in the document margins. The related ranges are highlighted by a different color for each reviewer.
Use the DXRichEditCommentOptions ‘s class properties to change the comment displaying options, such as range highlighting color or comment visibility.
Tip
Set the RichEditControl’s DocumentCapabilitiesOptions.Comments property to Disabled to disable comments.