StreamWriter.WriteAsync メソッド

定義

名前空間:
System.IO
アセンブリ:
System.IO.dll, mscorlib.dll, netstandard.dll, System.Runtime.Extensions.dll

データをストリームに非同期で書き込みます。Asynchronously writes data to the stream.

オーバーロード

WriteAsync(Char)

文字を非同期でストリームに書き込みます。Asynchronously writes a character to the stream.
WriteAsync(String)

文字列をストリームに非同期で書き込みます。Asynchronously writes a string to the stream.
WriteAsync(ReadOnlyMemory<Char>, CancellationToken)

文字メモリ領域をストリームに非同期で書き込みます。Asynchronously writes a character memory region to the stream.
WriteAsync(Char[], Int32, Int32)

文字の部分配列をストリームに非同期で書き込みます。Asynchronously writes a subarray of characters to the stream.

WriteAsync(Char)

文字を非同期でストリームに書き込みます。Asynchronously writes a character to the stream.

public:
 override System::Threading::Tasks::Task ^ WriteAsync(char value);
[System.Runtime.InteropServices.ComVisible(false)]
public override System.Threading.Tasks.Task WriteAsync (char value);
override this.WriteAsync : char -> System.Threading.Tasks.Task
Public Overrides Function WriteAsync (value As Char) As Task

パラメーター

value
Char

ストリームに書き込む文字。The character to write to the stream.

戻り値

Task

非同期の書き込み操作を表すタスク。A task that represents the asynchronous write operation.

属性
ComVisibleAttribute

例外

ObjectDisposedException

ストリーム ライターは破棄されます。The stream writer is disposed.

InvalidOperationException

ストリーム ライターは現在、前の書き込み操作で使用中です。The stream writer is currently in use by a previous write operation.

例

次の例では、WriteAsync(Char) メソッドを使用して、1つの文字 (文字 "a") をテキストファイルに書き込む方法を示します。The following example shows how to write a single character (the letter "a") to a text file by using the WriteAsync(Char) method.

using System;
using System.IO;

namespace ConsoleApplication
{
    class Program
    {
        static void Main(string[] args)
        {
            WriteCharacters();
        }

        static async void WriteCharacters()
        {
            using (StreamWriter writer = File.CreateText("newfile.txt"))
            {
                await writer.WriteAsync('a');
            }
        }
    }
}

Imports System.IO
Imports System.Text

Module Module1

    Sub Main()
        WriteCharacters()
    End Sub

    Async Sub WriteCharacters()
        Dim oneLetter As Char = "a"
        Using writer As StreamWriter = File.CreateText("newfile.txt")
            Await writer.WriteAsync(oneLetter)
        End Using
    End Sub
End Module

WriteAsync(String)

文字列をストリームに非同期で書き込みます。Asynchronously writes a string to the stream.

public:
 override System::Threading::Tasks::Task ^ WriteAsync(System::String ^ value);
[System.Runtime.InteropServices.ComVisible(false)]
public override System.Threading.Tasks.Task WriteAsync (string value);
override this.WriteAsync : string -> System.Threading.Tasks.Task
Public Overrides Function WriteAsync (value As String) As Task

パラメーター

value
String

ストリームに書き込む文字列。The string to write to the stream. value が null の場合は、何も書き込まれません。If value is null, nothing is written.

戻り値

Task

非同期の書き込み操作を表すタスク。A task that represents the asynchronous write operation.

属性
ComVisibleAttribute

例外

ObjectDisposedException

ストリーム ライターは破棄されます。The stream writer is disposed.

InvalidOperationException

ストリーム ライターは現在、前の書き込み操作で使用中です。The stream writer is currently in use by a previous write operation.

例

次の例は、WriteAsync(String) メソッドを使用してテキストファイルに文字列を書き込む方法を示しています。The following example shows how to write a string to a text file by using the WriteAsync(String) method.

using System;
using System.IO;

namespace ConsoleApplication
{
    class Program
    {
        static void Main(string[] args)
        {
            WriteCharacters();
        }

        static async void WriteCharacters()
        {
            using (StreamWriter writer = File.CreateText("newfile.txt"))
            {
                await writer.WriteAsync("Example text as string");
            }
        }
    }
}

Imports System.IO
Imports System.Text

Module Module1

    Sub Main()
        WriteCharacters()
    End Sub

    Async Sub WriteCharacters()

        Using writer As StreamWriter = File.CreateText("newfile.txt")
            Await writer.WriteAsync("Example text as string")
        End Using
    End Sub
End Module

WriteAsync(ReadOnlyMemory<Char>, CancellationToken)

文字メモリ領域をストリームに非同期で書き込みます。Asynchronously writes a character memory region to the stream.

public override System.Threading.Tasks.Task WriteAsync (ReadOnlyMemory<char> buffer, System.Threading.CancellationToken cancellationToken = null);
override this.WriteAsync : ReadOnlyMemory<char> * System.Threading.CancellationToken -> System.Threading.Tasks.Task

パラメーター

buffer
ReadOnlyMemory<Char>

ストリームに書き込む文字メモリ領域。The character memory region to write to the stream.

cancellationToken
CancellationToken

キャンセル要求を監視するためのトークン。The token to monitor for cancellation requests. 既定値は Noneです。The default value is None.

戻り値

Task

非同期の書き込み操作を表すタスク。A task that represents the asynchronous write operation.

WriteAsync(Char[], Int32, Int32)

文字の部分配列をストリームに非同期で書き込みます。Asynchronously writes a subarray of characters to the stream.

public:
 override System::Threading::Tasks::Task ^ WriteAsync(cli::array <char> ^ buffer, int index, int count);
[System.Runtime.InteropServices.ComVisible(false)]
public override System.Threading.Tasks.Task WriteAsync (char[] buffer, int index, int count);
override this.WriteAsync : char[] * int * int -> System.Threading.Tasks.Task
Public Overrides Function WriteAsync (buffer As Char(), index As Integer, count As Integer) As Task

パラメーター

buffer
Char[]

書き込むデータを格納する文字配列。A character array that contains the data to write.

index
Int32

データの読み取りを開始する、バッファー内の文字位置。The character position in the buffer at which to begin reading data.

count
Int32

書き込む文字の最大数。The maximum number of characters to write.

戻り値

Task

非同期の書き込み操作を表すタスク。A task that represents the asynchronous write operation.

属性
ComVisibleAttribute

例外

ArgumentNullException

buffer は null です。buffer is null.

ArgumentException

index に count を加算した値がバッファーの長さを超えています。The index plus count is greater than the buffer length.

ArgumentOutOfRangeException

index または count が負の値です。index or count is negative.

ObjectDisposedException

ストリーム ライターは破棄されます。The stream writer is disposed.

InvalidOperationException

ストリーム ライターは現在、前の書き込み操作で使用中です。The stream writer is currently in use by a previous write operation.

例

次の例では、WriteAsync(Char[], Int32, Int32) メソッドを使用して、テキストファイルに複数の文字を書き込む方法を示します。The following example shows how to write multiple characters to a text file by using the WriteAsync(Char[], Int32, Int32) method.

using System;
using System.Text;
using System.IO;

namespace ConsoleApplication
{
    class Program
    {
        static void Main(string[] args)
        {
            WriteCharacters();
        }

        static async void WriteCharacters()
        {
            UnicodeEncoding ue = new UnicodeEncoding();
            char[] charsToAdd = ue.GetChars(ue.GetBytes("Example string"));
            using (StreamWriter writer = File.CreateText("newfile.txt"))
            {
                await writer.WriteAsync(charsToAdd, 0, charsToAdd.Length);
            }
        }
    }
}

Imports System.IO
Imports System.Text

Module Module1

    Sub Main()
        WriteCharacters()
    End Sub

    Async Sub WriteCharacters()
        Dim ue As UnicodeEncoding = New UnicodeEncoding()
        Dim charsToAdd() = ue.GetChars(ue.GetBytes("Example string"))

        Using writer As StreamWriter = File.CreateText("newfile.txt")
            Await writer.WriteAsync(charsToAdd, 0, charsToAdd.Length)
        End Using
    End Sub
End Module

適用対象