如何在iphone的一个视图中对文本字段设置不同的最大字符限制？

i have a UIView with 10 UITextFields on it.i want to limit the different max character length on each UItextField.suppose on the first textfield the max length should be 17,for second and third it should be 2.how do i achieve this?i have a UIView with 10 UITextFields on it.i wa