How to set UIImage to UIBarButtonItem.

Monotouchで、UIBarButtonItemにUIImageを貼り付ける方法。
サイズ関係がちょっと戸惑った。

1、Import image file to project.

It is important to set build action "Content".
Build action > Content

2.Load Image and Set Image.

UIImage baseImage = UIImage.FromFile ("hoge.png");
UIImage scaledImage = baseImage.Scale (new SizeF (20.0f, 20.0f));
button.Image = scaledImage;

It is completed!

3.Extension methods

public static void SetImage(this UIBarButtonItem button , string fileName)
{
	if(!File.Exists(fileName))throw new FileNotFoundException(fileName);
	UIImage baseImage = UIImage.FromFile (fileName);
	UIImage scaledImage = baseImage.Scale (new SizeF(button.Width, 20.0f));
	button.Image = scaledImage;
}

.....
button.SetImage("hoge.png");

How can I do to get the Height of UIBarButtonItem?