Q:

How to change UIButton HighLight Color using Monotouch?

How to change UIButton HighLight Color using Monotouch?

A:

There is no direct way to do this. You must subclass UIButton and draw it your self when is is highlighted. This is a simple example:
public class CustomButton : UIButton
{

    public CustomButton(RectangleF frame)
    {

        this.Frame = frame;
        this.AddObserver(this, new NSString("Highlighted"), NSKeyValueObservingOptions.New, IntPtr.Zero);

    }

    public override void ObserveValue (NSString keyPath, NSObject ofObject, NSDictionary change, IntPtr context)
    {
        if (keyPath.ToString() == "Highlighted")
        {
            this.SetNeedsDisplay();
        }
    }

    public override void Draw (RectangleF rect)
    {
        base.Draw (rect);

        if (this.Highlighted)
        {
            // Draw for highlighted

        } else
        {

            // Draw for normal

        }
    }

}

I have translated this from this question, which has an Objective-C example: Here

A:

One possible way to do this, you will need to create a highlighted image for the button then use:
btn.SetImage(UIImage.FromBundle("Images/btnHighlighted.png"), UIControlState.Highlighted);

