IoC Scenario(dependency rejection.pdf)

public class TextEditor

{

private SpellChecker checker;

public TextEditor()//一个无参构造函数

{

checker = new SpellChecker();

}

}

public class TextEditor

{

private ISpellChecker checker;//代号1

public TextEditor(ISpellChecker checker)//假如 checker是3，就相当于程序员每次打这个函数时都要直接给checker赋值

{

this.checker = checker;//等号左边是代号1，等号右边是3

}

}