Question:You create a Microsoft ASP.NET application by using the Microsoft .NET Framework version 3.5. You create a custom
control named OrderForm.
You write the following code segment:
public delegate void CheckOrderFormEventHandler(EventArgs e);
private static readonly object CheckOrderFormKey = new object();
public event CheckOrderFormEventHandler CheckOrderForm
{
add { Events.AddHandler(CheckOrderFormKey, value); }
remove { Events.RemoveHandler(CheckOrderFormKey, value); }
}
You need to provide a method that enables the OrderForm control to raise the CheckOrderForm event.
Which code segment should you use?
A protected virtual void OnCheckOrderForm(EventArgs e) {
CheckOrderFormEventHandler checkOrderForm = (CheckOrderFormEventHandler)Events
[typeof(CheckOrderFormEventHandler)];
if (checkOrderForm != null)
checkOrderForm(e);
}B protected virtual void OnCheckOrderForm(EventArgs e) {
CheckOrderFormEventHandler checkOrderForm = Events[CheckOrderFormKey] as
CheckOrderFormEventHandler;
if (checkOrderForm != null)
checkOrderForm(e);
}C CheckOrderFormEventHandler checkOrderForm = new CheckOrderFormEventHandler
(checkOrderFormCallBack);
protected virtual void OnCheckOrderForm(EventArgs e) {
if (checkOrderForm != null)
checkOrderForm(e);
}D CheckOrderFormEventHandler checkOrderForm = new CheckOrderFormEventHandler
(checkOrderFormCallBack);
protected virtual void OnCheckOrderForm(EventArgs e) {
if (checkOrderForm != null)
RaiseBubbleEvent(checkOrderForm, e);
}
+ AnswerB
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