Question

I want to use the UIAccessibility informal protocol to set an accessibility trait on some views in MonoTouch. But there are no bindings. How can I do this?

Answer 1

The MonoTouch UIResponder.SetValueForKey(key,value) call can be used. Here are some extension methods to get and set the accessibility trait(s) of a control:

public static void SetAccessibilityTraits(this UIResponder responder, UIAccessibilityTraits traits)
{
    responder.SetValueForKey(NSNumber.FromUInt64((ulong)traits), new NSString("accessibilityTraits"));
}

public static UIAccessibilityTraits GetAccessibilityTraits(this UIResponder responder)
{
    var value = (NSNumber)responder.ValueForKey(new NSString("accessibilityTraits"));
    return (UIAccessibilityTraits)value.UInt64Value;
}

[Flags]
public enum UIAccessibilityTraits
{
    None = 0,
    Button = 1,
    Link = 2,
    SearchField = 1024,
    Image = 4,
    Selected = 8,
    PlaysSound = 16,
    KeyboardKey = 32,
    StaticText = 64,
    SummaryElement = 128,
    NotEnabled = 256,
    UpdatesFrequently = 512,
    StartsMediaSession = 2048,
    Adjustable = 4096,
    AllowsDirectInteraction = 8192,
    CausesPageTurn = 16384,
    Header = 65536    
}

Nic Wise has posted some other accessibility-related extension methods here. They let you set the accessibility label and hint for a control.