ConsoleCancelEventHandler Delegato
Importante
Alcune informazioni sono relative alla release non definitiva del prodotto, che potrebbe subire modifiche significative prima della release definitiva. Microsoft non riconosce alcuna garanzia, espressa o implicita, in merito alle informazioni qui fornite.
Rappresenta il metodo che gestirà l'evento CancelKeyPress di un oggetto Console.
public delegate void ConsoleCancelEventHandler(System::Object ^ sender, ConsoleCancelEventArgs ^ e);
public delegate void ConsoleCancelEventHandler(object? sender, ConsoleCancelEventArgs e);
public delegate void ConsoleCancelEventHandler(object sender, ConsoleCancelEventArgs e);
type ConsoleCancelEventHandler = delegate of obj * ConsoleCancelEventArgs -> unit
Public Delegate Sub ConsoleCancelEventHandler(sender As Object, e As ConsoleCancelEventArgs)
- sender
- Object
Origine dell'evento.
Oggetto ConsoleCancelEventArgs contenente i dati dell'evento.
Nell'esempio di codice seguente viene illustrato come usare la ConsoleCancelEventHandler classe per gestire un evento.
using namespace System;
void OnCancelKeyPressed(Object^ sender,
ConsoleCancelEventArgs^ args)
{
Console::WriteLine("{0}The read operation has been interrupted.",
Environment::NewLine);
Console::WriteLine(" Key pressed: {0}", args->SpecialKey);
Console::WriteLine(" Cancel property: {0}", args->Cancel);
// Set the Cancel property to true to prevent the process from
// terminating.
Console::WriteLine("Setting the Cancel property to true...");
args->Cancel = true;
// Announce the new value of the Cancel property.
Console::WriteLine(" Cancel property: {0}", args->Cancel);
Console::WriteLine("The read operation will resume...{0}",
Environment::NewLine);
}
int main()
{
// Clear the screen.
Console::Clear();
// Establish an event handler to process key press events.
Console::CancelKeyPress +=
gcnew ConsoleCancelEventHandler(OnCancelKeyPressed);
while (true)
{
// Prompt the user.
Console::Write("Press any key, or 'X' to quit, or ");
Console::WriteLine("CTRL+C to interrupt the read operation:");
// Start a console read operation. Do not display the input.
ConsoleKeyInfo^ keyInfo = Console::ReadKey(true);
// Announce the name of the key that was pressed .
Console::WriteLine(" Key pressed: {0}{1}", keyInfo->Key,
Environment::NewLine);
// Exit if the user pressed the 'X' key.
if (keyInfo->Key == ConsoleKey::X)
{
break;
}
}
}
// The example displays output similar to the following:
// Press any key, or 'X' to quit, or CTRL+C to interrupt the read operation:
// Key pressed: J
//
// Press any key, or 'X' to quit, or CTRL+C to interrupt the read operation:
// Key pressed: Enter
//
// Press any key, or 'X' to quit, or CTRL+C to interrupt the read operation:
//
// The read operation has been interrupted.
// Key pressed: ControlC
// Cancel property: False
// Setting the Cancel property to true...
// Cancel property: True
// The read operation will resume...
//
// Key pressed: Q
//
// Press any key, or 'X' to quit, or CTRL+C to interrupt the read operation:
// Key pressed: X
using System;
class Sample
{
public static void Main()
{
ConsoleKeyInfo cki;
Console.Clear();
// Establish an event handler to process key press events.
Console.CancelKeyPress += new ConsoleCancelEventHandler(myHandler);
while (true)
{
Console.Write("Press any key, or 'X' to quit, or ");
Console.WriteLine("CTRL+C to interrupt the read operation:");
// Start a console read operation. Do not display the input.
cki = Console.ReadKey(true);
// Announce the name of the key that was pressed .
Console.WriteLine($" Key pressed: {cki.Key}\n");
// Exit if the user pressed the 'X' key.
if (cki.Key == ConsoleKey.X) break;
}
}
protected static void myHandler(object sender, ConsoleCancelEventArgs args)
{
Console.WriteLine("\nThe read operation has been interrupted.");
Console.WriteLine($" Key pressed: {args.SpecialKey}");
Console.WriteLine($" Cancel property: {args.Cancel}");
// Set the Cancel property to true to prevent the process from terminating.
Console.WriteLine("Setting the Cancel property to true...");
args.Cancel = true;
// Announce the new value of the Cancel property.
Console.WriteLine($" Cancel property: {args.Cancel}");
Console.WriteLine("The read operation will resume...\n");
}
}
// The example displays output similar to the following:
// Press any key, or 'X' to quit, or CTRL+C to interrupt the read operation:
// Key pressed: J
//
// Press any key, or 'X' to quit, or CTRL+C to interrupt the read operation:
// Key pressed: Enter
//
// Press any key, or 'X' to quit, or CTRL+C to interrupt the read operation:
//
// The read operation has been interrupted.
// Key pressed: ControlC
// Cancel property: False
// Setting the Cancel property to true...
// Cancel property: True
// The read operation will resume...
//
// Key pressed: Q
//
// Press any key, or 'X' to quit, or CTRL+C to interrupt the read operation:
// Key pressed: X
open System
let myHandler sender (args: ConsoleCancelEventArgs) =
printfn "\nThe read operation has been interrupted."
printfn $" Key pressed: {args.SpecialKey}"
printfn $" Cancel property: {args.Cancel}"
// Set the Cancel property to true to prevent the process from terminating.
printfn "Setting the Cancel property to true..."
args.Cancel <- true
// Announce the new value of the Cancel property.
printfn $" Cancel property: {args.Cancel}"
printfn "The read operation will resume...\n"
// Establish an event handler to process key press events.
Console.CancelKeyPress.AddHandler(ConsoleCancelEventHandler myHandler)
let mutable quit = false
while not quit do
printf "Press any key, or 'X' to quit, or "
printfn "CTRL+C to interrupt the read operation:"
// Start a console read operation. Do not display the input.
let cki = Console.ReadKey true
// Announce the name of the key that was pressed .
printfn $" Key pressed: {cki.Key}\n"
// Exit if the user pressed the 'X' key.
if cki.Key = ConsoleKey.X then
quit <- true
// The example displays output similar to the following:
// Press any key, or 'X' to quit, or CTRL+C to interrupt the read operation:
// Key pressed: J
//
// Press any key, or 'X' to quit, or CTRL+C to interrupt the read operation:
// Key pressed: Enter
//
// Press any key, or 'X' to quit, or CTRL+C to interrupt the read operation:
//
// The read operation has been interrupted.
// Key pressed: ControlC
// Cancel property: False
// Setting the Cancel property to true...
// Cancel property: True
// The read operation will resume...
//
// Key pressed: Q
//
// Press any key, or 'X' to quit, or CTRL+C to interrupt the read operation:
// Key pressed: X
Class Sample
Public Shared Sub Main()
Dim cki As ConsoleKeyInfo
Console.Clear()
' Establish an event handler to process key press events.
AddHandler Console.CancelKeyPress, AddressOf myHandler
While True
Console.Write("Press any key, or 'X' to quit, or ")
Console.WriteLine("CTRL+C to interrupt the read operation:")
' Start a console read operation. Do not display the input.
cki = Console.ReadKey(True)
' Announce the name of the key that was pressed .
Console.WriteLine($" Key pressed: {cki.Key}{vbCrLf}")
' Exit if the user pressed the 'X' key.
If cki.Key = ConsoleKey.X Then Exit While
End While
End Sub
Protected Shared Sub myHandler(ByVal sender As Object, _
ByVal args As ConsoleCancelEventArgs)
Console.WriteLine($"{vbCrLf}The read operation has been interrupted.")
Console.WriteLine($" Key pressed: {args.SpecialKey}")
Console.WriteLine($" Cancel property: {args.Cancel}")
' Set the Cancel property to true to prevent the process from terminating.
Console.WriteLine("Setting the Cancel property to true...")
args.Cancel = True
' Announce the new value of the Cancel property.
Console.WriteLine($" Cancel property: {args.Cancel}")
Console.WriteLine($"The read operation will resume...{vbCrLf}")
End Sub
End Class
' The example diplays output similar to the following:
' Press any key, or 'X' to quit, or CTRL+C to interrupt the read operation:
' Key pressed: J
'
' Press any key, or 'X' to quit, or CTRL+C to interrupt the read operation:
' Key pressed: Enter
'
' Press any key, or 'X' to quit, or CTRL+C to interrupt the read operation:
'
' The read operation has been interrupted.
' Key pressed: ControlC
' Cancel property: False
' Setting the Cancel property to true...
' Cancel property: True
' The read operation will resume...
'
' Key pressed: Q
'
' Press any key, or 'X' to quit, or CTRL+C to interrupt the read operation:
' Key pressed: X
Quando si crea un delegato ConsoleCancelEventHandler, si identifica il metodo che gestirà l'evento. Per associare l'evento al gestore eventi in uso, aggiungere all'evento un'istanza del delegato. Il gestore eventi viene chiamato ogni volta che si verifica l'evento, a meno che non venga rimosso il delegato. Per altre informazioni sui delegati del gestore eventi, vedere Gestione e generazione di eventi.
Get |
Ottiene un oggetto che rappresenta il metodo rappresentato dal delegato specificato. |
Prodotto | Versioni |
---|---|
.NET | Core 1.0, Core 1.1, Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9 |
.NET Framework | 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1 |
.NET Standard | 1.3, 1.4, 1.6, 2.0, 2.1 |
Feedback su .NET
.NET è un progetto di open source. Selezionare un collegamento per fornire feedback: