**EPPlus supports threaded comments from version 5.3. With threaded comments users can add comments to a thread that belongs to a cell in a worksheet. The users can mention eachother in the comments and the entire thread can be resolved (closed/locked) and re-opened. EPPlus 5 supports all of these features. Threaded comments exists in several spreadsheet programs, however the EPPlus 5 implementation is designed to cover most of the functionality in Excel/Office 365.** **For backward compatibility cells with a threaded comments also contains a "legacy comment", that replicates the content of the thread. This comment will be overwritten with new content when opened in a spreadsheet program that supports threaded comments.** ## ThreadedCommentPersons When a user adds a threaded comment in Excel/Office 365 the user is added to the `ThreadedCommentPersons` collection in the workbook. With EPPlus 5 and up you can read/edit/delete these persons, see code below. ```csharp var persons = package.Workbook.ThreadedCommentPersons; ``` ```vbnet Dim persons = package.Workbook.ThreadedCommentPersons ``` You can add a new person this way: ```csharp var p1 = persons.Add("John Doe"); //This method call above is using default parameters same as below var p2 = persons.Add("John Doe", "John Doe", IdentityProvider.NoProvider); ``` ```vbnet Dim p1 = persons.Add("John Doe") 'This method call above is using default parameters same as below Dim p2 = persons.Add("John Doe", "John Doe", IdentityProvider.NoProvider) ``` The collection of `ThreadedCommentPerson` is also available via the worksheet (this is editing the same underlying data as when you use the property on the worksheet), see code below. ```csharp var sheet = package.Workbook.Worksheets.First(); var author = sheet.ThreadedComments.Persons.First(); ``` ```vbnet Dim sheet = package.Workbook.Worksheets.First() Dim author = sheet.ThreadedComments.Persons.First() ``` The `Persons` collection exposes functions for an indexer (numeric index and id (string)) and properties/methods such as `Count`, `Find`, `Remove`. ### IdentityProvider enum This enum represent the for different sources that are supported: - `NoProvider` - The person is not represented in a catalog outside the workbook - `ActiveDirectory` - The person corresponds to an Active directory user. Person's userId should be an ActiveDirectory Security Identifier (SID). - `WindowsLiveId` - The person corresponds to a Windows Live user. Person's userId should be a 64-bit signed decimal that uniquely identifies a user on Windows Live. - `Office365` - The person corresponds to an Office 365 user. The Person's userId should be a string that uniquely identifies a user. It SHOULD be comprised of three individual values separated by a "::" delimiter. - `PeoplePicker` - The person corresponds to a People Picker user. The Persons userId should be an email address provided by People Picker. Read more about managing persons here: [https://docs.microsoft.com/en-us/openspecs/office\_standards/ms-xlsx/6274371e-7c5c-46e3-b661-cbeb4abfe968]() ## Adding comments The comment threads can be accessed either on worksheet level or directly via a cell. ```csharp using (var package = new ExcelPackage()) { var sheet = package.Workbook.Worksheets.Add("test"); var person = sheet.ThreadedComments.Persons.Add("John Doe"); var person2 = sheet.ThreadedComments.Persons.Add("Jane Doe"); var thread = sheet.Cells["A1"].AddThreadedComment(); var c1 = thread.AddComment(person2.Id, "Hello"); // Mention Jane Doe (person2) in the comment. var c2 = thread.AddComment(person.Id, "Hello {0}, how are you?", person2); } ``` ```vbnet Using package As New ExcelPackage() Dim sheet = package.Workbook.Worksheets.Add("test") Dim person = sheet.ThreadedComments.Persons.Add("John Doe") Dim person2 = sheet.ThreadedComments.Persons.Add("Jane Doe") Dim thread = sheet.Cells("A1").AddThreadedComment() Dim c1 = thread.AddComment(person2.Id, "Hello") ' Mention Jane Doe (person2) in the comment. Dim c2 = thread.AddComment(person.Id, "Hello {0}, how are you?", person2) End Using ``` This code will result in this thread: ### Mentions You can mention one or more persons in a comment. Continuing with the code above, we can mention both John and Jane like this ```csharp var person3 = sheet.ThreadedComments.Persons.Add("IT Support"); thread.AddComment(person3.Id, "Hello {0} and {1}, do you need any assistance today?", person, person2); ``` ```vbnet Dim person3 = sheet.ThreadedComments.Persons.Add("IT Support") thread.AddComment(person3.Id, "Hello {0} and {1}, do you need any assistance today?", person, person2) ``` As you can see, the way of inserting mentions works similar to the .NET `string.Format` method. You can mention a person more than once in a comment, but only the first occurance will be a "proper" mention. The mentions in a comment can be read using the comments `Mentions` property. ```csharp foreach(var mention in c2.Mentions) { var id = mention.MentionId; var mentionPersonId = mention.MentionPersonId; var startIndex = mention.StartIndex; var length = mention.Length; } ``` ```vbnet For Each mention In c2.Mentions Dim id = mention.MentionId Dim mentionPersonId = mention.MentionPersonId Dim startIndex = mention.StartIndex Dim length = mention.Length Next ``` ### Notifications In Office 365, when a user inserts a mention in a comment an email is sent as a notification to the mentioned person. Please note that EPPlus doesn't send notifications. If you want to send notifications when you create a mention you need to use data from the `Persons` collection, connect to your IdentityProvider and retrieve the information needed to send a notification. ### Edit a comment The `Text` property of a comment is readonly. Use the `EditText` function to change the text of an existing comment. With the `EditText` function you can set a new text on the comment with or without mentions. ```csharp c2.EditText("Hello"); c2.EditText("Hello {0}, I have edited your comment!", person); ``` ```vbnet c2.EditText("Hello") c2.EditText("Hello {0}, I have edited your comment!", person) ``` ## Resolve/Re-open a thread You can resolve (lock the thread for new comments) and re-open a thread by using the `ResolveThread` and `ReopenThread` methods. ```csharp sheet1.ThreadedComments["A1"].ResolveThread(); sheet1.ThreadedComments["A1"].ReopenThread(); ``` ```vbnet sheet1.ThreadedComments("A1").ResolveThread() sheet1.ThreadedComments("A1").ReopenThread() ``` --- ## See also - [Sample 1.5-C\#]() and [Sample 1.5-VB]() - [Comments/Notes]()