Windows Store: SecondaryTile.Exists(tileId) - TileId seems to have some undocumented limitations?

Question

Can anyone shed some light on the below?

What are the exact rules for tileId. Length limit, character limits?

Obviously looked here, but nothing: http://msdn.microsoft.com/library/windows/apps/BR242183

Found this post, but nothing about length limitations: http://social.msdn.microsoft.com/Forums/en-US/winappswithcsharp/thread/b3cb317c-edca-46c1-8dfa-7979f12c96b6/ Also his assertions about character limitations don't hold true for me - I can use characters he says are banned.

Thanks,

Jon

When i == 65:

[System.ArgumentException] = {"The parameter is incorrect.\r\n"}

        string concat = "";

        for (int i = 0; i < 70; i++)
        {
            try
            {
                var boo = SecondaryTile.Exists(concat);
                Debug.WriteLine("{0} {1}", boo, i);
                concat = concat + ".";
            }
            catch (Exception ex)
            {
                continue;
            }
        }

        return;

Output:

False 0
False 1
... Truncated for brevity
False 63
False 64

Answer 1

It's documented in this constructor overload:

A string that will uniquely identify the tile within your app's package. Choose a unique ID that is descriptive and meaningful to your app. It is limited to 64 characters and must begin with a number or letter and be composed of the characters a-z, A-Z, 0-9, period (.), or underscore (_). If you provide the same ID as that of an existing secondary tile, the existing secondary tile will be overwritten. Can be set or retrieved through the TileId property.

(It's also documented in the TileId property.)