How to call Guide.BeginShowMessageBox

Question

I have a problem calling Guide.BeginShowMessageBox

Here is my code:

public object FuelTypeIndex { get; private set; }

private void PhoneApplicationPage_Loaded(object sender, RoutedEventArgs e)
{
    var messageCommands = new Dictionary<string, Action>()
    {
        {  "Diesel", () => {FuelTypeIndex = 0;}},
        {  "Petrol", () => {FuelTypeIndex = 1;}},
        {  "Other", () => {FuelTypeIndex = 2;}},
    };

    var result = Guide.BeginShowMessageBox("Title", "Message", messageCommands.Keys, 0, MessageBoxIcon.Warning, null, null);
    result.AsyncWaitHandle.WaitOne();

    int? choice = Guide.EndShowMessageBox(result);
    if (choice.HasValue)
        messageCommands.ElementAt(choice.Value).Value.Invoke();
}

I get the following exception:

An exception of type 'System.ArgumentException' occurred in Microsoft.Xna.Framework.GamerServices.ni.dll but was not handled in user code

Additional information: The argument is invalid. It must contain between 1 and 2 strings. The strings cannot be null or empty, and must be less than 256 characters long.

By debugging I located the problem to messageCommands.Keys, because if I call the function with a static array it works just fine.

So what am I doing wrong?

Answer 1

The problem is the number of requested buttons in the call to Guide.BeginShowMessageBox. According to the documentation the maximum number of buttons is two on Windows Phone.