Simple chat

For a quick question, a short exchange, or any scenario where you do not need multiple parallel conversations, use SendMessageAsync without managing sessions yourself. The engine creates and tracks a current session implicitly and uses it across calls.

When to use this pattern

  • Single question and single answer.
  • A short back-and-forth where every message belongs to the same conversation.
  • CLI tools, scripts, or test harnesses that run one conversation at a time.
  • Prototypes where session management is not yet needed.

For concurrent conversations (e.g., multiple users) or scenarios that need explicit control over session IDs, use Multi-turn chat with StartNewChatAsync and SendMessageToSessionAsync.

Prerequisites

Minimal example

using Aspose.LLM;
using Aspose.LLM.Abstractions.Parameters.Presets;

var license = new Aspose.LLM.License();
license.SetLicense("Aspose.LLM.lic");

var preset = new Qwen25Preset();
using var api = AsposeLLMApi.Create(preset);

string reply = await api.SendMessageAsync("What is 2 + 2?");
Console.WriteLine(reply);
// Output: 2 + 2 equals 4.

Each call to SendMessageAsync without a session ID uses or creates the current session. Sequential calls form one coherent conversation:

await api.SendMessageAsync("My name is Alice.");
string reply = await api.SendMessageAsync("What is my name?");
Console.WriteLine(reply);
// Output: Your name is Alice.

Override the preset for one message

Pass a different preset to a single call without changing the default:

using Aspose.LLM.Abstractions.Parameters.Presets;

// Default preset used by the API
var defaultPreset = new Qwen25Preset();
using var api = AsposeLLMApi.Create(defaultPreset);

// Use a more deterministic preset for this one question
var strictPreset = new Qwen25Preset();
strictPreset.SamplerParameters.Temperature = 0.1f;

string reply = await api.SendMessageAsync(
    "What is the square root of 144?",
    preset: strictPreset);

Console.WriteLine(reply);
// Output: The square root of 144 is 12.

The override applies only to the message. Subsequent calls without a preset argument continue to use defaultPreset.

Cancellation

Pass a CancellationToken to abort long generations:

using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(30));

try
{
    string reply = await api.SendMessageAsync(
        "Write a 500-word essay about migration patterns of the Arctic tern.",
        cancellationToken: cts.Token);
    Console.WriteLine(reply);
}
catch (OperationCanceledException)
{
    Console.WriteLine("Generation timed out.");
}

The CancellationToken stops token generation. The partial output is discarded; the session state is not corrupted, so you can continue the conversation with the next call.

Full runnable example

using Aspose.LLM;
using Aspose.LLM.Abstractions.Parameters.Presets;

internal class SimpleChatDemo
{
    public static async Task Main()
    {
        var license = new Aspose.LLM.License();
        license.SetLicense("Aspose.LLM.lic");

        var preset = new Qwen25Preset();
        using var api = AsposeLLMApi.Create(preset);

        Console.WriteLine("Ask me anything. Type 'quit' to exit.");
        while (true)
        {
            Console.Write("> ");
            string? line = Console.ReadLine();
            if (line == null || line.Equals("quit", StringComparison.OrdinalIgnoreCase))
                break;

            try
            {
                string reply = await api.SendMessageAsync(line);
                Console.WriteLine(reply);
            }
            catch (Exception ex)
            {
                Console.WriteLine($"Error: {ex.Message}");
            }
        }
    }
}

Run:

dotnet run

Common errors

  • Not licensed for this method — apply a license before calling any chat method. See Licensing.
  • Only one AsposeLLMApi instance can be created at a time — an earlier instance has not been disposed. Keep one instance for the process lifetime.
  • Slow first response — the engine downloads native binaries and the model file on first Create. Expect 5-15 minutes on a fresh machine. Subsequent runs use the local cache.

What’s next

Multi-turn chat