将一个对象传递给Windows窗体的eventandler

我已经搜索了几个小时，但我似乎找不到答案。我觉得好像有一个简单的答案，我只是把头撞在墙上试图找到它。

private void Form1_Load(object sender, EventArgs e)
{
     ......bunch of code here...
     GroupBoxController GBControl = new GroupBoxController(groupbox1);
}
private void nextbutton_Click(object sender, EventArgs e)
{
     .....I want to be able to access GBControl and modify in here ..........
}

谢谢你的任何可能解决这个问题的答案。

private GroupBoxController GBControl;
private void Form1_Load(object sender, EventArgs e)
{
     ......bunch of code here...
     GBControl = new GroupBoxController(groupbox1);
}
private void nextbutton_Click(object sender, EventArgs e)
{
     GBControl.Whatever();
}