= simple_form_for @foo do |f|

  # this works
  = f.hidden_field :asdf,:value => @some.thing

  # this works
  = f.input :asdf,:as => "hidden",:input_html => { :value => @some.thing }

  # Why doesn't this work,exactly?
  = f.input :title,:value => @some.thing

当我查看我的日志时,我看到该值在后一个输入中以空字符串形式出现,但我不清楚为什么会发生这种情况.