<StackPanel
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
  <TextBlock FontSize="100">⌀</TextBlock>
  <Label FontSize="100">⌀</Label>
</StackPanel>

bool CachedFontProvider::FamilyExists(const Uri& baseUri, const char* familyName)
{
    Uri folder;
    NormalizeFolder(baseUri, folder);

    Families& families = GetFolder(folder);
    Families::Iterator it = families.Find(familyName);

    if (it != families.End())
    {
        return true;
    }
    else
    {
        for (Families::Bucket& family : families)
        {
            if (StrCaseStartsWith(familyName, family.key.Str()))
            {
                return true;
            }
        }
    }

    return false;
}