Console.Read Metoda

Definice

Obor názvů:

System

Sestavení:

netstandard.dll, System.Console.dll

Zdroj:

Console.cs

Přečte další znak ze standardního vstupního datového proudu.

public:
 static int Read();

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

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

Public Shared Function Read () As Integer

Návraty

Int32

Další znak ze vstupního datového proudu nebo záporný znak (-1), pokud aktuálně nejsou k dispozici žádné další znaky ke čtení.

Atributy

UnsupportedOSPlatformAttribute

Výjimky

IOException

Došlo k vstupně-výstupní chybě.

Příklady

Následující příklad ukazuje metodu Read .

// 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.
'

Poznámky

Metoda Read blokuje její návrat při zadávání znaků; ukončí se při stisknutí klávesy Enter . Stisknutím klávesy Enter připojíte ke vstupu posloupnost ukončení řádku závislá na platformě (například Windows připojí posloupnost návratového řádku řádku). Následná volání metody Read načtou vstupní jeden znak najednou. Po načtení Read posledního znaku zablokuje jeho návrat znovu a cyklus se opakuje.

Důležité

Metoda ReadLine nebo KeyAvailable vlastnost a ReadKey metoda jsou vhodnější než použití Read metody.

Všimněte si, že metoda nevrací -1, pokud neprovedete jednu z následujících akcí:

• Současně stiskněte modifikační klávesu Control a Z klávesu konzoly (Ctrl+Z), která signalizuje podmínku ukončení souboru. Pokud používáte Windows, musíte také stisknout klávesu konzoly Enter .

• Stiskněte ekvivalentní klávesu, která signalizuje podmínku konce souboru, například funkční klávesu F6 ve Windows.

• Přesměrujte vstupní datový proud na zdroj, například textový soubor, který má skutečný znak konce souboru.

Viz také

• ReadLine()
• Write(String, Object)
• WriteLine()