我有两个表单,Form1和Form2。在Form1中有一个按钮,当我点击它时,会打开Form2并隐藏Form1。
但是现在,如果我关闭Form2并显示Form1,我不知道该怎么做。
第二个问题: 如果我在Form1中为元素(标签、按钮)编写了Update()方法,那么我可以在Form2中使用这个方法吗?
谢谢
您需要使用 FormClosing
事件。在创建 form2
的代码中,将您的 form1
附加到关闭事件上。这样,您的 form1
就会知道 form2
正在被关闭。
private void OpenForm()
{
var form2 = new Form2();
form2.FormClosing += FormIsClosing;
form2.Show();
this.Hide();
}
private void FormIsClosing(object sender, FormClosingEventArgs e)
{
if (e.Cancel)
{
return;
}
this.Show();
this.Update();
}
你所提出的两个问题都可以通过事件轻松解决。以下是代码:
Form1:
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
//Declare your new form
Form2 form2 = new Form2();
//Register the update event
form2.updateEvent += new EventHandler(handleUpdateEvent);
//Register form closed event
form2.FormClosed += new FormClosedEventHandler(form2_FormClosed);
Visible = false;
//Show your new form
form2.Show();
}
void form2_FormClosed(object sender, FormClosedEventArgs e)
{
this.Visible = true;
}
//Handler for the event from form 2
void handleUpdateEvent(object sender, EventArgs e)
{
this.BackColor = Color.Red;
}
}
public partial class Form2 : Form
{
//Declare your event
public event EventHandler updateEvent;
public Form2()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
//If the event is registered fire it, otherwise do nothing
if (updateEvent != null)
{
//fire the event and give our custom event args some text
updateEvent(sender, e);
}
}
private void button2_Click(object sender, EventArgs e)
{
//Another way to close the form, beside clicking the red "X"
Close();
}
}