helper to determine if radio/checkbox needs to be checked

moneypenny () — Thu, 07 Sep 2006 16:25:27 GMT

I frequently have to use methods such as 'radio_button' and 'check_box_tag' when I don't have an object with a method that will automatically determine the value of the input field. Therefore, I have to check to see if a certain parameter has been passed, and if so, if the parameter's value matches that of the input's value. This method does that.

It's designed to be used in a Rails helper. You can either pass it the object, method, and value (the same parameters as, for example, radio_button) or name and value (the same parameters as radio_button_tag).

def checked?( *args )

  if args.length == 3

    object, method, value = args

    if params[object] && params[object][method] && params[object][method] == value

      'checked'

    end

  elsif args.length == 2

    name, value = args

    if params[name] && params[name] == value

      true

    end

  end

end

Here's an example usage:
<%= radio_button 'person', 'age', '12', :checked => checked?( 'person', 'age', '12' ) %>

If params[:person][:age] exists and it equals '12', then 'checked?' returns 'checked'; otherwise, it returns nil.

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helper to determine if radio/checkbox needs to be checked