How can you broadcast a message to all connected clients in SignalR?

Question

Utpal Vishwas · Answer

Broadcasting a message to all connected clients in SignalR is straightforward and one of its core features.
How to broadcast to all clients in a SignalR Hub?
Inside your Hub class on the server, you use:
await Clients.All.SendAsync("MethodName", parameters...);
Clients.All targets every connected client."MethodName" is the name of the client-side method that will be invoked.parameters... are the data you want to send.
Example: Broadcasting a chat message to everyone
public class ChatHub : Hub
{
    public async Task SendMessage(string user, string message)
    {
        // Broadcast to all connected clients
        await Clients.All.SendAsync("ReceiveMessage", user, message);
    }
}
On the client side, you listen for "ReceiveMessage":
connection.on("ReceiveMessage", (user, message) =andgt; {
    console.log(`${user}: ${message}`);
    // Update UI or perform actions with the message
});
Summary
Action
Code snippet
Broadcast message
await Clients.All.SendAsync("ReceiveMessage", user, message);
Listen on client
connection.on("ReceiveMessage", handlerFunction);
Read More
What is SignalR and how does it work in real-time web applications?How do you set up a basic SignalR Hub in an ASP.NET Core application?What are the different transport protocols SignalR can use for communication?How do clients connect to a SignalR Hub and send messages?

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How can you broadcast a message to all connected clients in SignalR?

Utpal Vishwas

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1 Answers

How to broadcast to all clients in a SignalR Hub?

Example: Broadcasting a chat message to everyone

On the client side, you listen for `"ReceiveMessage"`:

Summary

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Action	Code snippet
Broadcast message	`await Clients.All.SendAsync("ReceiveMessage", user, message);`
Listen on client	`connection.on("ReceiveMessage", handlerFunction);`