Console.Read Metod
Definition
Viktigt
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Läser nästa tecken från standardindataströmmen.
public:
static int Read();
[System.Runtime.Versioning.UnsupportedOSPlatform("android")]
[System.Runtime.Versioning.UnsupportedOSPlatform("browser")]
public static int Read();
[System.Runtime.Versioning.UnsupportedOSPlatform("browser")]
public static int Read();
public static int Read();
[<System.Runtime.Versioning.UnsupportedOSPlatform("android")>]
[<System.Runtime.Versioning.UnsupportedOSPlatform("browser")>]
static member Read : unit -> int
[<System.Runtime.Versioning.UnsupportedOSPlatform("browser")>]
static member Read : unit -> int
static member Read : unit -> int
Public Shared Function Read () As Integer
Returer
Nästa tecken från indataströmmen eller negativt (-1) om det för närvarande inte finns fler tecken att läsa.
- Attribut
Undantag
Ett I/O-fel uppstod.
Exempel
I följande exempel visas Read metoden.
// 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.
'
Kommentarer
Metoden blockerar dess retur medan du skriver indatatecken. Den Read avslutas när du trycker på tangenten Enter . Om du trycker på Retur läggs en plattformsberoende radavslutssekvens till dina indata (till exempel Windows lägger till en vagnreturlinjematningssekvens). Efterföljande anrop till Read metoden hämtar dina indata ett tecken i taget. När det sista tecknet har hämtats Read blockerar det returen igen och cykeln upprepas.
Important
Metoden ReadLine eller egenskapen KeyAvailable och ReadKey metoden är att föredra framför att använda Read metoden.
Observera att metoden inte returnerar -1 om du inte utför någon av följande åtgärder:
Tryck samtidigt på modifierarnyckeln Control och Z konsolnyckeln (Ctrl+Z), vilket signalerar tillståndet för filslut. Om du är på Windows måste du också trycka på konsolnyckeln Enter.
Tryck på en motsvarande nyckel som signalerar tillståndet för filslut, till exempel F6-funktionsnyckeln i Windows.
Omdirigera indataströmmen till en källa, till exempel en textfil, som har ett verkligt filslutstecken.