This topic applies to SDK v3 release. You can find the documentation for the latest version of the SDK v4 here.
The Connector uses an Activity object to pass information back and forth between bot and channel (user). The most common type of activity is message, but there are other activity types that can be used to communicate various types of information to a bot or channel.
Activity types in the Bot Builder SDK for .NET
The following activity types are supported by the Bot Builder SDK for .NET.
|message||IMessageActivity||Represents a communication between bot and user.|
|conversationUpdate||IConversationUpdateActivity||Indicates that the bot was added to a conversation, other members were added to or removed from the conversation, or conversation metadata has changed.|
|contactRelationUpdate||IContactRelationUpdateActivity||Indicates that the bot was added or removed from a user's contact list.|
|typing||ITypingActivity||Indicates that the user or bot on the other end of the conversation is compiling a response.|
|deleteUserData||n/a||Indicates to a bot that a user has requested that the bot delete any user data it may have stored.|
|endOfConversation||IEndOfConversationActivity||Indicates the end of a conversation.|
|event||IEventActivity||Represents a communication sent to a bot that is not visible to the user.|
|invoke||IInvokeActivity||Represents a communication sent to a bot to request that it perform a specific operation. This activity type is reserved for internal use by the Microsoft Bot Framework.|
|messageReaction||IMessageReactionActivity||Indicates that a user has reacted to an existing activity. For example, a user clicks the "Like" button on a message.|
Your bot will send message activities to communicate information to and receive message activities from users. Some messages may simply consist of plain text, while others may contain richer content such as text to be spoken, suggested actions, media attachments, rich cards, and channel-specific data. For information about commonly-used message properties, see Create messages.
A bot receives a conversationUpdate activity whenever it has been added to a conversation, other members have been added to or removed from a conversation, or conversation metadata has changed.
If members have been added to the conversation, the activity's
MembersAdded property will contain an array of
ChannelAccount objects to identify the new members.
To determine whether your bot has been added to the conversation (i.e., is one of the new members), evaluate whether the
Recipient.Id value for the activity (i.e., your bot's id)
Id property for any of the accounts in the
If members have been removed from the conversation, the
MembersRemoved property will contain an array of
ChannelAccount objects to identify the removed members.
If your bot receives a conversationUpdate activity indicating that a user has joined the conversation, you may choose to have it respond by sending a welcome message to that user.
A bot receives a contactRelationUpdate activity whenever it is added to or removed from a user's contact list. The value of the activity's
Action property (add | remove) indicates whether the bot has been added or removed from the user's contact list.
A bot receives a typing activity to indicate that the user is typing a response. A bot may send a typing activity to indicate to the user that it is working to fulfill a request or compile a response.
A bot receives a deleteUserData activity when a user requests deletion of any data that the bot has previously persisted for him or her. If your bot receives this type of activity, it should delete any personally identifiable information (PII) that it has previously stored for the user that made the request.
A bot receives an endOfConversation activity to indicate that the user has ended the conversation. A bot may send an endOfConversation activity to indicate to the user that the conversation is ending.
Your bot may receive an event activity from an external process or service that wants to communicate information to your bot without that information being visible to users. The sender of an event activity typically does not expect the bot to acknowledge receipt in any way.
Your bot may receive an invoke activity that represents a request for it to perform a specific operation. The sender of an invoke activity typically expects the bot to acknowledge receipt via HTTP response. This activity type is reserved for internal use by the Microsoft Bot Framework.
Some channels will send messageReaction activities to your bot when a user reacted to an existing activity. For example, a user clicks the "Like" button on a message. The ReplyToId property will indicate which activity the user reacted to.
The messageReaction activity may correspond to any number of messageReactionTypes that the channel defined. For example, "Like" or "PlusOne" as reaction types that a channel may send.