Console.KeyAvailable Propriété

Définition

Obtient une valeur indiquant si l'appui sur une touche est disponible dans le flux d'entrée.Gets a value indicating whether a key press is available in the input stream.

public:
 static property bool KeyAvailable { bool get(); };
public static bool KeyAvailable { get; }
member this.KeyAvailable : bool
Public Shared ReadOnly Property KeyAvailable As Boolean

Valeur de propriété

true si l'appui sur une touche est disponible, sinon, false.true if a key press is available; otherwise, false.

Exceptions

Une erreur d'E/S s'est produite.An I/O error occurred.

L’entrée standard est redirigée vers un fichier au lieu du clavier.Standard input is redirected to a file instead of the keyboard.

Exemples

L’exemple suivant montre comment utiliser la KeyAvailable propriété pour créer une boucle qui s’exécute jusqu’à ce qu’une touche soit enfoncée.The following example demonstrates how to use the KeyAvailable property to create a loop that runs until a key is pressed.

using namespace System;
using namespace System::Threading;
int main()
{
   ConsoleKeyInfo cki;
   do
   {
      Console::WriteLine( "\nPress a key to display; press the 'x' key to quit." );
      
      // Your code could perform some useful task in the following loop. However, 
      // for the sake of this example we'll merely pause for a quarter second.
      while ( Console::KeyAvailable == false )
            Thread::Sleep( 250 );
      cki = Console::ReadKey( true );
      Console::WriteLine( "You pressed the '{0}' key.", cki.Key );
   }
   while ( cki.Key != ConsoleKey::X );
}

/*
This example produces results similar to the following:

Press a key to display; press the 'x' key to quit.
You pressed the 'H' key.

Press a key to display; press the 'x' key to quit.
You pressed the 'E' key.

Press a key to display; press the 'x' key to quit.
You pressed the 'PageUp' key.

Press a key to display; press the 'x' key to quit.
You pressed the 'DownArrow' key.

Press a key to display; press the 'x' key to quit.
You pressed the 'X' key.
*/
using System;
using System.Threading;

class Sample 
{
    public static void Main() 
    {
       ConsoleKeyInfo cki;

       do {
           Console.WriteLine("\nPress a key to display; press the 'x' key to quit.");

           // Your code could perform some useful task in the following loop. However, 
           // for the sake of this example we'll merely pause for a quarter second.
   
           while (Console.KeyAvailable == false)
               Thread.Sleep(250); // Loop until input is entered.
           
           cki = Console.ReadKey(true);
           Console.WriteLine("You pressed the '{0}' key.", cki.Key);
        } while(cki.Key != ConsoleKey.X);
    }
}
/*
This example produces results similar to the following:

Press a key to display; press the 'x' key to quit.
You pressed the 'H' key.

Press a key to display; press the 'x' key to quit.
You pressed the 'E' key.

Press a key to display; press the 'x' key to quit.
You pressed the 'PageUp' key.

Press a key to display; press the 'x' key to quit.
You pressed the 'DownArrow' key.

Press a key to display; press the 'x' key to quit.
You pressed the 'X' key.
*/
Imports System.Threading

Class Sample
   Public Shared Sub Main()
      Dim cki As ConsoleKeyInfo
      
      Do
         Console.WriteLine(vbCrLf & "Press a key to display; press the 'x' key to quit.")

         ' Your code could perform some useful task in the following loop. However, 
         ' for the sake of this example we'll merely pause for a quarter second.
         
         While Console.KeyAvailable = False
            Thread.Sleep(250) ' Loop until input is entered.
         End While
         cki = Console.ReadKey(True)
         Console.WriteLine("You pressed the '{0}' key.", cki.Key)
      Loop While cki.Key <> ConsoleKey.X
   End Sub 
End Class 
'This example produces results similar to the following:
'
'Press a key to display; press the 'x' key to quit.
'You pressed the 'H' key.
'
'Press a key to display; press the 'x' key to quit.
'You pressed the 'E' key.
'
'Press a key to display; press the 'x' key to quit.
'You pressed the 'PageUp' key.
'
'Press a key to display; press the 'x' key to quit.
'You pressed the 'DownArrow' key.
'
'Press a key to display; press the 'x' key to quit.
'You pressed the 'X' key.
'

Remarques

La valeur de propriété est retournée immédiatement ; autrement dit, la KeyAvailable propriété ne bloque pas l’entrée tant qu’une pression de touche n’est pas disponible.The property value is returned immediately; that is, the KeyAvailable property does not block input until a key press is available.

Utilisez la KeyAvailable propriété conjointement uniquement avec la ReadKey méthode, et non avec Read les ReadLine méthodes ou.Use the KeyAvailable property in conjunction with only the ReadKey method, not the Read or ReadLine methods.

S’applique à