MDI子表格C＃

Question

单击“ X”按钮时如何检查MDI子窗体的关闭事件，并让父窗体知道它已关闭？

Answer 1

您可以简单地听MDI中的FormClosed事件。

var childForm = new ChildForm();
childForm.FormClosed += new FormClosedEventHandler(form_FormClosed);
childForm.Show();

Answer 2

在FormClosing事件中，您可以执行

TheMainForm form = (TheMainForm)this.MdiParent()
form.AlertMe( this );

Answer 3

从mainForm内将关闭事件附加到子窗体

Form mdiChild = new Form();
mdiChild.MdiParent = this;
mdiChild.Closed += (s, e) => { //... };
mdiChild.Show();

没有检查代码，但不应该那么难

Answer 4

很好，下面的代码显示了父窗体如何识别子窗体是否已关闭，还可以识别出是否有任何新的子窗体添加到该父窗体。

private List<Form> ChildFormList = new List<Form>();

private void MyForm_MdiChildActivate(object sender, EventArgs e)
{
   Form f = this.ActiveMdiChild;

   if (f == null)
   {
    //the last child form was just closed
    return;
   }

   if (!ChildFormList.Contains(f))
   {
      //a new child form was created
      ChildFormList.Add(f);
      f.FormClosed += new FormClosedEventHandler(ChildFormClosed); // here the parent form knows that that child form has been closed or not
  }
  else
  {
    //activated existing form
  }
}
private void ChildFormClosed(object sender, FormClosedEventArgs e)
{
   //a child form was closed
    Form f = (Form)sender;
    ChildFormList.Remove(f);
}