如何在button1中实例化类obj并在button2中使用obj方法

问题描述

private void button1_Click(object sender, EventArgs e)
        {
            Cat kitty = new Cat();
        }

        private void button2_Click(object sender, EventArgs e)
        {
           //kitty.eat();
        }

如何通过button2访问kitty.eat（）？

现在kitty在当前情况下不退出。





谢谢。



我尝试了什么：

how to access kitty.eat() by button2?
now kitty is not exit in the current context.


thank you.

What I have tried:

private Cat button1_Click(object sender, EventArgs e)

或由EventArgs完成？

or done by EventArgs ?

推荐答案

Cat kitty;  // declare outside
       private void button1_Click(object sender, EventArgs e)
       {
           kitty = new Cat();
       }

       private void button2_Click(object sender, EventArgs e)
       {
           if (kitty != null)  // validate for null value.
               kitty.eat();
       }

{
   int a = 1;
   if (a == 1)
      {
      int b = 2;
      } // b goes out of scope here
   a = b; // Illegal: b is not in scope and is not available
} // a goes out of scope here

要分享 两个处理程序之间的变量，将定义移到任何方法之外：

To "share" the variable between the two handlers, move the definition outside any method:

private Cat kitty = null;
private void button1_Click(object sender, EventArgs e)
    {
    kitty = new Cat();
    }

private void button2_Click(object sender, EventArgs e)
    {
    kitty.eat();
    }

这篇关于如何在button1中实例化类obj并在button2中使用obj方法的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！