我将提供一个基于接口的解决方案。这样做可以让您轻松地统一管理应用程序是否可以关闭。使用以下实现,父窗体负责询问子窗口是否准备好关闭,子窗口执行必要的操作并回复主窗口。
假设我有接口
IManagedForm
:
interface IManagedForm
{
bool CanIBeClosed(Object someParams);
}
这两种形式(Form1
和ChildForm
)都需要实现它。
需要注意的是,对于此示例,我是以这种方式实例化ChildForm
:
ChildForm cf = new ChildForm() { Owner = this, Name = "ChildForm" };
cf.Show();
首先是由 Form1
实现接口:
private void Form1_FormClosing(object sender, FormClosingEventArgs e)
{
object someArgsInterestingForTheMethod = new object();
e.Cancel = !((IManagedForm)this).CanIBeClosed(someArgsInterestingForTheMethod);
}
public bool CanIBeClosed(object someParams)
{
bool isOKforClosing = true;
var cf = this.Controls["ChildForm"] as IManagedForm;
if (cf != null)
{
isOKforClosing = cf.CanIBeClosed(someParams);
if (!isOKforClosing)
{
MessageBox.Show("ChildForm does not allow me to close.", "Form1", MessageBoxButtons.OK);
}
}
return isOKforClosing;
}
最后,你的ChildForm
接口实现看起来会像这样:
private void ChildForm_FormClosing(object sender, FormClosingEventArgs e)
{
object someArgsInterestingForTheMethod = new object();
e.Cancel = !((IManagedForm)this).CanIBeClosed(someArgsInterestingForTheMethod);
}
public bool CanIBeClosed(object someParams)
{
bool meetConditions = ValidateClosingConditions(someParams);
bool iAmReadyToBeClosed = true;
if (!meetConditions)
{
switch (MessageBox.Show("Save changes before exit?", "MyChildForm", MessageBoxButtons.YesNoCancel, MessageBoxIcon.Question))
{
case DialogResult.Yes:
iAmReadyToBeClosed = true;
break;
case DialogResult.No:
iAmReadyToBeClosed = true;
break;
case DialogResult.Cancel:
iAmReadyToBeClosed = false;
break;
}
}
return iAmReadyToBeClosed;
}
public bool ValidateClosingConditions(object someParams)
{
Random rnd = new Random();
return ((rnd.Next(10) % 2) == 0);
}
希望您能理解得足够清楚。