StringWriter 类
定义
重要
一些信息与预发行产品相关，相应产品在发行之前可能会进行重大修改。 对于此处提供的信息，Microsoft 不作任何明示或暗示的担保。
实现用于将信息写入字符串的 TextWriter。 信息存储在基础 StringBuilder中。
public ref class StringWriter : System::IO::TextWriterpublic class StringWriter : System.IO.TextWriter[System.Serializable]
public class StringWriter : System.IO.TextWriter[System.Serializable]
[System.Runtime.InteropServices.ComVisible(true)]
public class StringWriter : System.IO.TextWritertype StringWriter = class
inherit TextWriter[<System.Serializable>]
type StringWriter = class
inherit TextWriter[<System.Serializable>]
[<System.Runtime.InteropServices.ComVisible(true)>]
type StringWriter = class
inherit TextWriterPublic Class StringWriter
Inherits TextWriter- 继承
- 继承
- 属性
示例
下面的代码示例演示如何从一组双空格句子创建连续段落，然后将段落转换回原始文本。
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() );
}
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 = (char)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());
}
}
Option Explicit
Option Strict
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
注解
StringWriter 使你能够以同步或异步方式写入字符串。 可以使用 Write(Char) 或 WriteAsync(Char) 方法、使用 Write(String) 或 WriteAsync(String) 方法一次编写字符串。 此外，还可以使用 WriteLineAsync 方法之一异步编写字符、字符数组或字符串后跟行终止符。
注意
此类型实现 IDisposable 接口，但实际上没有任何要释放的资源。 这意味着不需要直接调用 Dispose() 或使用 using（在 C# 中）或 Using（在 Visual Basic 中）等语言构造来释放它。
下表列出了其他典型或相关的 I/O 任务的示例。
| 要执行此操作... | 请参阅本主题中的示例... |
|---|---|
| 创建文本文件。 | 如何：将文本写入文件 |
| 写入文本文件。 | 如何：将文本写入文件 |
| 从文本文件中读取。 | 如何：从文件读取文本 |
| 将文本追加到文件中。 |
如何：打开日志文件并将其追加到日志文件 File.AppendText FileInfo.AppendText |
| 获取文件的大小。 | FileInfo.Length |
| 获取文件的属性。 | File.GetAttributes |
| 设置文件的属性。 | File.SetAttributes |
| 确定文件是否存在。 | File.Exists |
| 从二进制文件读取。 | 如何：读取和写入新创建的数据文件 |
| 写入二进制文件。 | 如何：读取和写入新创建的数据文件 |
构造函数
| StringWriter() |
初始化 StringWriter 类的新实例。 |
| StringWriter(IFormatProvider) |
使用指定的格式控件初始化 StringWriter 类的新实例。 |
| StringWriter(StringBuilder) |
初始化写入指定 StringBuilder的 StringWriter 类的新实例。 |
| StringWriter(StringBuilder, IFormatProvider) |
初始化 StringWriter 类的新实例，该实例写入指定的 StringBuilder 并具有指定的格式提供程序。 |
字段
| CoreNewLine |
存储用于此 |
属性
| Encoding |
获取在其中写入输出的 Encoding。 |
| FormatProvider |
获取一个对象，该对象控制格式设置。 (继承自 TextWriter) |
| NewLine |
获取或设置当前 |
方法
显式接口实现
| IDisposable.Dispose() |
有关此成员的说明，请参阅 Dispose()。 (继承自 TextWriter) |
扩展方法
| ConfigureAwait(IAsyncDisposable, Boolean) |
配置如何执行从异步可释放项返回的任务的 await。 |
