StringReader-Klasse
Implementiert einen TextReader, der aus einer Zeichenfolge liest.
Namespace: System.IO
Assembly: mscorlib (in mscorlib.dll)
Syntax
'Declaration
<SerializableAttribute> _
<ComVisibleAttribute(True)> _
Public Class StringReader
Inherits TextReader
'Usage
Dim instance As StringReader
[SerializableAttribute]
[ComVisibleAttribute(true)]
public class StringReader : TextReader
[SerializableAttribute]
[ComVisibleAttribute(true)]
public ref class StringReader : public TextReader
/** @attribute SerializableAttribute() */
/** @attribute ComVisibleAttribute(true) */
public class StringReader extends TextReader
SerializableAttribute
ComVisibleAttribute(true)
public class StringReader extends TextReader
Hinweise
In der folgenden Tabelle sind Beispiele für andere typische oder verwandte E/A-Aufgaben aufgeführt.
Aufgabe |
Beispiel in diesem Thema |
|---|---|
Eine Textdatei erstellen. |
|
In eine Textdatei schreiben. |
|
Aus einer Textdatei lesen. |
|
Text an eine Datei anfügen. |
|
Die Größe einer Datei abrufen. |
|
Die Attribute einer Datei abrufen. |
|
Die Attribute einer Datei festlegen. |
|
Bestimmen, ob eine Datei vorhanden ist. |
|
Aus einer Binärdatei lesen. |
Gewusst wie: Lesen und Schreiben einer neu erstellten Datendatei |
In eine Binärdatei schreiben. |
Gewusst wie: Lesen und Schreiben einer neu erstellten Datendatei |
Beispiel
Das folgende Codebeispiel veranschaulicht das Erstellen eines fortlaufenden Absatzes aus einer Gruppe von Sätzen mit doppelten Leerzeichen und das Zurückkonvertieren des Absatzes in den Ausgangstext.
Option Explicit
Option Strict
Imports Microsoft.VisualBasic
Imports System
Imports System.IO
Public Class StrReader
Shared Sub Main()
Dim textReaderText As String = "TextReader is the " & _
"abstract base class of StreamReader and " & _
"StringReader, which read characters from streams " & _
"and strings, respectively." & _
vbCrLf & vbCrLf & _
"Create an instance of TextReader to open a text " & _
"file for reading a specified range of characters, " & _
"or to create a reader based on an existing stream." & _
vbCrLf & vbCrLf & _
"You can also use an instance of TextReader to read " & _
"text from a custom backing store using the same " & _
"APIs you would use for a string or a stream." & _
vbCrLf & vbCrLf
Console.WriteLine("Original text:" & vbCrLf & vbCrLf & _
textReaderText)
' From textReaderText, create a continuous paragraph
' with two spaces between each sentence.
Dim aLine, aParagraph As String
Dim strReader As New StringReader(textReaderText)
While True
aLine = strReader.ReadLine()
If aLine Is Nothing Then
aParagraph = aParagraph & vbCrLf
Exit While
Else
aParagraph = aParagraph & aLine & " "
End If
End While
Console.WriteLine("Modified text:" & vbCrLf & vbCrLf & _
aParagraph)
' Re-create textReaderText from aParagraph.
Dim intCharacter As Integer
Dim convertedCharacter As Char
Dim strWriter As New StringWriter()
strReader = New StringReader(aParagraph)
While True
intCharacter = strReader.Read()
' Check for the end of the string
' before converting to a character.
If intCharacter = -1 Then
Exit While
End If
convertedCharacter = Convert.ToChar(intCharacter)
If convertedCharacter = "."C Then
strWriter.Write("." & vbCrLf & vbCrLf)
' Bypass the spaces between sentences.
strReader.Read()
strReader.Read()
Else
strWriter.Write(convertedCharacter)
End If
End While
Console.WriteLine(vbCrLf & "Original text:" & vbCrLf & _
vbCrLf & strWriter.ToString())
End Sub
End Class
using System;
using System.IO;
class StringRW
{
static void Main()
{
string textReaderText = "TextReader is the abstract base " +
"class of StreamReader and StringReader, which read " +
"characters from streams and strings, respectively.\n\n" +
"Create an instance of TextReader to open a text file " +
"for reading a specified range of characters, or to " +
"create a reader based on an existing stream.\n\n" +
"You can also use an instance of TextReader to read " +
"text from a custom backing store using the same " +
"APIs you would use for a string or a stream.\n\n";
Console.WriteLine("Original text:\n\n{0}", textReaderText);
// From textReaderText, create a continuous paragraph
// with two spaces between each sentence.
string aLine, aParagraph = null;
StringReader strReader = new StringReader(textReaderText);
while(true)
{
aLine = strReader.ReadLine();
if(aLine != null)
{
aParagraph = aParagraph + aLine + " ";
}
else
{
aParagraph = aParagraph + "\n";
break;
}
}
Console.WriteLine("Modified text:\n\n{0}", aParagraph);
// Re-create textReaderText from aParagraph.
int intCharacter;
char convertedCharacter;
StringWriter strWriter = new StringWriter();
strReader = new StringReader(aParagraph);
while(true)
{
intCharacter = strReader.Read();
// Check for the end of the string
// before converting to a character.
if(intCharacter == -1) break;
convertedCharacter = Convert.ToChar(intCharacter);
if(convertedCharacter == '.')
{
strWriter.Write(".\n\n");
// Bypass the spaces between sentences.
strReader.Read();
strReader.Read();
}
else
{
strWriter.Write(convertedCharacter);
}
}
Console.WriteLine("\nOriginal text:\n\n{0}",
strWriter.ToString());
}
}
using namespace System;
using namespace System::IO;
int main()
{
String^ textReaderText = "TextReader is the abstract base "
"class of StreamReader and StringReader, which read "
"characters from streams and strings, respectively.\n\n"
"Create an instance of TextReader to open a text file "
"for reading a specified range of characters, or to "
"create a reader based on an existing stream.\n\n"
"You can also use an instance of TextReader to read "
"text from a custom backing store using the same "
"APIs you would use for a string or a stream.\n\n";
Console::WriteLine( "Original text:\n\n{0}", textReaderText );
// From textReaderText, create a continuous paragraph
// with two spaces between each sentence.
String^ aLine;
String^ aParagraph;
StringReader^ strReader = gcnew StringReader( textReaderText );
while ( true )
{
aLine = strReader->ReadLine();
if ( aLine != nullptr )
{
aParagraph = String::Concat( aParagraph, aLine, " " );
}
else
{
aParagraph = String::Concat( aParagraph, "\n" );
break;
}
}
Console::WriteLine( "Modified text:\n\n{0}", aParagraph );
// Re-create textReaderText from aParagraph.
int intCharacter;
Char convertedCharacter;
StringWriter^ strWriter = gcnew StringWriter;
strReader = gcnew StringReader( aParagraph );
while ( true )
{
intCharacter = strReader->Read();
// Check for the end of the string
// before converting to a character.
if ( intCharacter == -1 )
break;
convertedCharacter = Convert::ToChar( intCharacter );
if ( convertedCharacter == '.' )
{
strWriter->Write( ".\n\n" );
// Bypass the spaces between sentences.
strReader->Read();
strReader->Read();
}
else
{
strWriter->Write( convertedCharacter );
}
}
Console::WriteLine( "\nOriginal text:\n\n{0}", strWriter->ToString() );
}
import System.*;
import System.IO.*;
class StringRW
{
public static void main(String[] args)
{
String textReaderText = "TextReader is the abstract base "
+ "class of StreamReader and StringReader, which read "
+ "characters from streams and strings, respectively.\n\n"
+ "Create an instance of TextReader to open a text file "
+ "for reading a specified range of characters, or to "
+ "create a reader based on an existing stream.\n\n"
+ "You can also use an instance of TextReader to read "
+ "text from a custom backing store using the same "
+ "APIs you would use for a string or a stream.\n\n";
Console.WriteLine("Original text:\n\n{0}", textReaderText);
// From textReaderText, create a continuous paragraph
// with two spaces between each sentence.
String aParagraph = "";
String aLine;
StringReader strReader = new StringReader(textReaderText);
while (true) {
aLine = strReader.ReadLine();
if (aLine != null) {
aParagraph = aParagraph + aLine + " ";
}
else {
aParagraph = aParagraph + "\n";
break ;
}
}
Console.WriteLine("Modified text:\n\n{0}", aParagraph);
// Re-create textReaderText from aParagraph.
int intCharacter;
char convertedCharacter;
StringWriter strWriter = new StringWriter();
strReader = new StringReader(aParagraph);
while (true) {
intCharacter = strReader.Read();
// Check for the end of the string
// before converting to a character.
if (intCharacter == -1) {
break ;
}
convertedCharacter = Convert.ToChar(intCharacter);
if (convertedCharacter == '.') {
strWriter.Write(".\n\n");
// Bypass the spaces between sentences.
strReader.Read();
strReader.Read();
}
else {
strWriter.Write(convertedCharacter);
}
}
Console.WriteLine("\nOriginal text:\n\n{0}", strWriter.ToString());
} //main
} //StringRW
Vererbungshierarchie
System.Object
System.MarshalByRefObject
System.IO.TextReader
System.IO.StringReader
Threadsicherheit
Alle öffentlichen statischen (Shared in Visual Basic) Member dieses Typs sind threadsicher. Bei Instanzmembern ist die Threadsicherheit nicht gewährleistet.
Plattformen
Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile für Pocket PC, Windows Mobile für Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition
.NET Framework unterstützt nicht alle Versionen sämtlicher Plattformen. Eine Liste der unterstützten Versionen finden Sie unter Systemanforderungen.
Versionsinformationen
.NET Framework
Unterstützt in: 2.0, 1.1, 1.0
.NET Compact Framework
Unterstützt in: 2.0, 1.0
Siehe auch
Referenz
StringReader-Member
System.IO-Namespace
TextReader
StringWriter
Weitere Ressourcen
Datei- und Stream-E/A
Gewusst wie: Lesen aus einer Textdatei
Gewusst wie: Schreiben von Text in eine Datei