Console.Read Método

Referencia

Definición

Espacio de nombres:: System

Ensamblado:: System.Console.dll

Ensamblado:: mscorlib.dll

Ensamblado:: netstandard.dll

Importante

Parte de la información hace referencia a la versión preliminar del producto, que puede haberse modificado sustancialmente antes de lanzar la versión definitiva. Microsoft no otorga ninguna garantía, explícita o implícita, con respecto a la información proporcionada aquí.

Lee el siguiente carácter del flujo de entrada estándar.

public:
 static int Read();

[System.Runtime.Versioning.UnsupportedOSPlatform("browser")]
public static int Read ();

[System.Runtime.Versioning.UnsupportedOSPlatform("browser")]
[System.Runtime.Versioning.UnsupportedOSPlatform("android")]
public static int Read ();

public static int Read ();

[<System.Runtime.Versioning.UnsupportedOSPlatform("browser")>]
static member Read : unit -> int

[<System.Runtime.Versioning.UnsupportedOSPlatform("browser")>]
[<System.Runtime.Versioning.UnsupportedOSPlatform("android")>]
static member Read : unit -> int

static member Read : unit -> int

Public Shared Function Read () As Integer

Devoluciones

Int32

El carácter siguiente del flujo de entrada o menos uno (-1) si no hay actualmente más caracteres que leer.

Atributos: UnsupportedOSPlatformAttribute

Excepciones

IOException

Error de E/S.

Ejemplos

En el siguiente ejemplo se muestra el Read método.

// This example demonstrates the Console.Read() method.
using namespace System;
int main()
{
   String^ m1 = "\nType a string of text then press Enter. "
   "Type '+' anywhere in the text to quit:\n";
   String^ m2 = "Character '{0}' is hexadecimal 0x{1:x4}.";
   String^ m3 = "Character     is hexadecimal 0x{0:x4}.";
   Char ch;
   int x;
   
   //
   Console::WriteLine( m1 );
   do
   {
      x = Console::Read();
      try
      {
         ch = Convert::ToChar( x );
         if ( Char::IsWhiteSpace( ch ) )
         {
            Console::WriteLine( m3, x );
            if ( ch == 0x0a )
                        Console::WriteLine( m1 );
         }
         else
                  Console::WriteLine( m2, ch, x );
      }
      catch ( OverflowException^ e ) 
      {
         Console::WriteLine( "{0} Value read = {1}.", e->Message, x );
         ch = Char::MinValue;
         Console::WriteLine( m1 );
      }

   }
   while ( ch != '+' );
}

/*
This example produces the following results:

Type a string of text then press Enter. Type '+' anywhere in the text to quit:

The quick brown fox.
Character 'T' is hexadecimal 0x0054.
Character 'h' is hexadecimal 0x0068.
Character 'e' is hexadecimal 0x0065.
Character     is hexadecimal 0x0020.
Character 'q' is hexadecimal 0x0071.
Character 'u' is hexadecimal 0x0075.
Character 'i' is hexadecimal 0x0069.
Character 'c' is hexadecimal 0x0063.
Character 'k' is hexadecimal 0x006b.
Character     is hexadecimal 0x0020.
Character 'b' is hexadecimal 0x0062.
Character 'r' is hexadecimal 0x0072.
Character 'o' is hexadecimal 0x006f.
Character 'w' is hexadecimal 0x0077.
Character 'n' is hexadecimal 0x006e.
Character     is hexadecimal 0x0020.
Character 'f' is hexadecimal 0x0066.
Character 'o' is hexadecimal 0x006f.
Character 'x' is hexadecimal 0x0078.
Character '.' is hexadecimal 0x002e.
Character     is hexadecimal 0x000d.
Character     is hexadecimal 0x000a.

Type a string of text then press Enter. Type '+' anywhere in the text to quit:

^Z
Value was either too large or too small for a character. Value read = -1.

Type a string of text then press Enter. Type '+' anywhere in the text to quit:

+
Character '+' is hexadecimal 0x002b.

*/

// This example demonstrates the Console.Read() method.
using System;

class Sample
{
    public static void Main()
    {
    string m1 = "\nType a string of text then press Enter. " +
                "Type '+' anywhere in the text to quit:\n";
    string m2 = "Character '{0}' is hexadecimal 0x{1:x4}.";
    string m3 = "Character     is hexadecimal 0x{0:x4}.";
    char ch;
    int x;
//
    Console.WriteLine(m1);
    do
        {
        x = Console.Read();
        try
            {
            ch = Convert.ToChar(x);
            if (Char.IsWhiteSpace(ch))
               {
               Console.WriteLine(m3, x);
               if (ch == 0x0a)
                   Console.WriteLine(m1);
               }
            else
                {
                    Console.WriteLine(m2, ch, x);
                }
            }
        catch (OverflowException e)
            {
            Console.WriteLine("{0} Value read = {1}.", e.Message, x);
            ch = Char.MinValue;
            Console.WriteLine(m1);
            }
        } while (ch != '+');
    }
}
/*
This example produces the following results:

Type a string of text then press Enter. Type '+' anywhere in the text to quit:

The quick brown fox.
Character 'T' is hexadecimal 0x0054.
Character 'h' is hexadecimal 0x0068.
Character 'e' is hexadecimal 0x0065.
Character     is hexadecimal 0x0020.
Character 'q' is hexadecimal 0x0071.
Character 'u' is hexadecimal 0x0075.
Character 'i' is hexadecimal 0x0069.
Character 'c' is hexadecimal 0x0063.
Character 'k' is hexadecimal 0x006b.
Character     is hexadecimal 0x0020.
Character 'b' is hexadecimal 0x0062.
Character 'r' is hexadecimal 0x0072.
Character 'o' is hexadecimal 0x006f.
Character 'w' is hexadecimal 0x0077.
Character 'n' is hexadecimal 0x006e.
Character     is hexadecimal 0x0020.
Character 'f' is hexadecimal 0x0066.
Character 'o' is hexadecimal 0x006f.
Character 'x' is hexadecimal 0x0078.
Character '.' is hexadecimal 0x002e.
Character     is hexadecimal 0x000d.
Character     is hexadecimal 0x000a.

Type a string of text then press Enter. Type '+' anywhere in the text to quit:

^Z
Value was either too large or too small for a character. Value read = -1.

Type a string of text then press Enter. Type '+' anywhere in the text to quit:

+
Character '+' is hexadecimal 0x002b.

*/

// This example demonstrates the Console.Read() method.
open System

// string m2 = "Character '{0}' is hexadecimal 0x{1:x4}.";
// string m3 = "Character     is hexadecimal 0x{0:x4}.";
// char ch;

printfn "\nType a string of text then press Enter. Type '+' anywhere in the text to quit:\n"

let mutable ch = ' '
let mutable x = 0

while ch <> '+' do
    x <- Console.Read()
    try
        ch <- Convert.ToChar x
        if Char.IsWhiteSpace ch then
            printfn $"Character     is hexadecimal 0x{x:x4}."
            if ch = char '\u000A' then
                printfn "\nType a string of text then press Enter. Type '+' anywhere in the text to quit:\n"
        else
            printfn $"Character '{ch}' is hexadecimal 0x{x:x4}." 
    
    with :? OverflowException as e ->
        printfn $"{e.Message} Value read = {x}."
        ch <- Char.MinValue
        printfn "\nType a string of text then press Enter. Type '+' anywhere in the text to quit:\n"


// This example produces the following results:
//
// Type a string of text then press Enter. Type '+' anywhere in the text to quit:
//
// The quick brown fox.
// Character 'T' is hexadecimal 0x0054.
// Character 'h' is hexadecimal 0x0068.
// Character 'e' is hexadecimal 0x0065.
// Character     is hexadecimal 0x0020.
// Character 'q' is hexadecimal 0x0071.
// Character 'u' is hexadecimal 0x0075.
// Character 'i' is hexadecimal 0x0069.
// Character 'c' is hexadecimal 0x0063.
// Character 'k' is hexadecimal 0x006b.
// Character     is hexadecimal 0x0020.
// Character 'b' is hexadecimal 0x0062.
// Character 'r' is hexadecimal 0x0072.
// Character 'o' is hexadecimal 0x006f.
// Character 'w' is hexadecimal 0x0077.
// Character 'n' is hexadecimal 0x006e.
// Character     is hexadecimal 0x0020.
// Character 'f' is hexadecimal 0x0066.
// Character 'o' is hexadecimal 0x006f.
// Character 'x' is hexadecimal 0x0078.
// Character '.' is hexadecimal 0x002e.
// Character     is hexadecimal 0x000d.
// Character     is hexadecimal 0x000a.
//
// Type a string of text then press Enter. Type '+' anywhere in the text to quit:
//
// ^Z
// Value was either too large or too small for a character. Value read = -1.
//
// Type a string of text then press Enter. Type '+' anywhere in the text to quit:
//
// +
// Character '+' is hexadecimal 0x002b.

' This example demonstrates the Console.Read() method.
Class Sample
   Public Shared Sub Main()
      Dim m1 As String = _
                vbCrLf & _
                "Type a string of text then press Enter. " & _
                "Type '+' anywhere in the text to quit:" & _
                vbCrLf
      Dim m2 As String = "Character '{0}' is hexadecimal 0x{1:x4}."
      Dim m3 As String = "Character     is hexadecimal 0x{0:x4}."
      Dim ch As Char
      Dim x As Integer
      '
      Console.WriteLine(m1)
      Do
         x = Console.Read()
         Try
            ch = Convert.ToChar(x)
            If Char.IsWhiteSpace(ch) Then
               Console.WriteLine(m3, x)
               If ch = vbLf Then
                  Console.WriteLine(m1)
               End If
            Else
               Console.WriteLine(m2, ch, x)
            End If
         Catch e As OverflowException
            Console.WriteLine("{0} Value read = {1}.", e.Message, x)
            ch = Char.MinValue
            Console.WriteLine(m1)
         End Try
      Loop While ch <> "+"c
   End Sub
End Class
'
'This example produces the following results:
'
'Type a string of text then press Enter. Type '+' anywhere in the text to quit:
'
'The quick brown fox.
'Character 'T' is hexadecimal 0x0054.
'Character 'h' is hexadecimal 0x0068.
'Character 'e' is hexadecimal 0x0065.
'Character     is hexadecimal 0x0020.
'Character 'q' is hexadecimal 0x0071.
'Character 'u' is hexadecimal 0x0075.
'Character 'i' is hexadecimal 0x0069.
'Character 'c' is hexadecimal 0x0063.
'Character 'k' is hexadecimal 0x006b.
'Character     is hexadecimal 0x0020.
'Character 'b' is hexadecimal 0x0062.
'Character 'r' is hexadecimal 0x0072.
'Character 'o' is hexadecimal 0x006f.
'Character 'w' is hexadecimal 0x0077.
'Character 'n' is hexadecimal 0x006e.
'Character     is hexadecimal 0x0020.
'Character 'f' is hexadecimal 0x0066.
'Character 'o' is hexadecimal 0x006f.
'Character 'x' is hexadecimal 0x0078.
'Character '.' is hexadecimal 0x002e.
'Character     is hexadecimal 0x000d.
'Character     is hexadecimal 0x000a.
'
'Type a string of text then press Enter. Type '+' anywhere in the text to quit:
'
'^Z
'Value was either too large or too small for a character. Value read = -1.
'
'Type a string of text then press Enter. Type '+' anywhere in the text to quit:
'
'+
'Character '+' is hexadecimal 0x002b.
'

Comentarios

El Read método bloquea su valor devuelto mientras escribe caracteres de entrada; finaliza al presionar la Enter tecla. Al presionar Entrar, se anexa una secuencia de terminación de línea dependiente de la plataforma a la entrada (por ejemplo, Windows anexa una secuencia de retorno de línea de retorno de carro). Las llamadas posteriores al Read método recuperan el carácter de entrada a la vez. Una vez recuperado el carácter final, Read bloquea su retorno de nuevo y el ciclo se repite.

Importante

El ReadLine método, o la propiedad y ReadKey el KeyAvailable método son preferibles a usar el Read método .

Tenga en cuenta que el método no devuelve -1 a menos que realice una de las siguientes acciones:

Presione simultáneamente la tecla modificadora y Z la Control tecla de consola (Ctrl+Z), que indica la condición de fin de archivo. Si está en Windows, también debe presionar la tecla de consolaEnter.
Presione una tecla equivalente que señale la condición de fin de archivo, como la tecla de función F6 en Windows.
Redirija el flujo de entrada a un origen, como un archivo de texto, que tenga un carácter de fin de archivo real.

Se aplica a

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