委托子窗体刷新父窗体

//Form1
public Form1()
{
InitializeComponent();
}

private void button1_Click(object sender, EventArgs e)
{
Form2 f2 = new Form2();
f2.ee += Refreshs;
f2.ShowDialog();
}

public void Refreshs(object sender, EventArgs e)
{
label1.Text = DateTime.Now.ToString();
}

//Form2

public partial class Form2 : Form
{

public event EventHandler ee ;

public Form2()
{
InitializeComponent();
}

private void button1_Click(object sender, EventArgs e)
{
ee(null,null);
}
}