microsoft/semantic-kernel · error · InvalidOperationException

Invalid choice

Error message

Invalid choice

What it means

Thrown by the default arm of a console-menu switch in the Amazon Bedrock Models sample. Cases 1-4 dispatch to chat/text/stream demos; any other value falls through to a hard InvalidOperationException. It is a programmer/user-input guard, not a library error, so the message 'Invalid choice' refers to the menu digit entered at runtime.

Source

Thrown at dotnet/samples/Demos/AmazonBedrockModels/Program.cs:34

// Get user choice
int choice = GetUserChoice();

switch (choice)
{
    case 1:
        await PerformChatCompletion().ConfigureAwait(false);
        break;
    case 2:
        await PerformTextGeneration().ConfigureAwait(false);
        break;
    case 3:
        await PerformStreamChatCompletion().ConfigureAwait(false);
        break;
    case 4:
        await PerformStreamTextGeneration().ConfigureAwait(false);
        break;
    default:
        throw new InvalidOperationException("Invalid choice");
}

async Task PerformChatCompletion()
{
    string userInput;
    ChatHistory chatHistory = [];

    // Get available chat completion models
    var availableChatModels = bedrockModels.Values
        .Where(m => m.Modalities.Contains(ModelDefinition.SupportedModality.ChatCompletion))
        .ToDictionary(m => bedrockModels.Single(kvp => kvp.Value.Name == m.Name).Key, m => m.Name);

    // Show user what models are available and let them choose
    int chosenModel = GetModelNumber(availableChatModels, "chat completion");

    var kernel = Kernel.CreateBuilder().AddBedrockChatCompletionService(availableChatModels[chosenModel]).Build();
    var chatCompletionService = kernel.GetRequiredService<IChatCompletionService>();

View on GitHub (pinned to c028a0c7dc)

Solutions

1. Re-run the sample and enter a digit strictly between 1 and 4.
2. If scripting the demo, clamp/validate the parsed integer before the switch and re-prompt on invalid input.
3. If you extended the menu, add the new case branch before the default so valid new options do not throw.

Example fix

// before
default:
    throw new InvalidOperationException("Invalid choice");

// after
int choice;
while (!int.TryParse(Console.ReadLine(), out choice) || choice < 1 || choice > 4)
{
    Console.Write("Enter a number from 1 to 4: ");
}
switch (choice) { /* cases 1-4, no default throw */ }

int choice;
while (!int.TryParse(Console.ReadLine(), out choice) || choice < 1 || choice > 4)
{
    Console.Write("Enter a number from 1 to 4: ");
}
// choice is now guaranteed valid; the default throw is unreachable

static bool IsValidMenuChoice(string input, out int value) =>
    int.TryParse(input, out value) && value is >= 1 and <= 4;

When it happens

Trigger: The user types a number outside 1-4 (e.g. 0, 5, 9) or a non-integer string that was parsed to a value outside the supported range and reached the `default` branch of the switch at Program.cs:34.

Common situations: Running the interactive demo and mistyping the menu option, an automated script feeding an out-of-range index, or the menu being extended with new cases without updating valid input bounds.

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AI-assisted analysis of microsoft/semantic-kernel@c028a0c7dc (2026-08-13). Data as JSON: /api/errors/17e746a705451fa9. Report an issue: GitHub.