StringWriter.WriteAsync 方法

定義

命名空間:: System.IO

組件:: mscorlib.dll, System.IO.dll

組件:: mscorlib.dll

組件:: System.IO.dll

組件:: netstandard.dll

重要

部分資訊涉及發行前產品，在發行之前可能會有大幅修改。 Microsoft 對此處提供的資訊，不做任何明確或隱含的瑕疵擔保。

非同步寫入資料到字串。

多載

名稱	Description
WriteAsync(Char)	非同步地將字元寫入字串。
WriteAsync(String)	非同步地將字串寫入目前的字串。
WriteAsync(ReadOnlyMemory<Char>, CancellationToken)	非同步地將記憶體區域的字元寫入字串。
WriteAsync(Char[], Int32, Int32)	非同步地將一個字元子陣列寫入字串。

WriteAsync(Char)

非同步地將字元寫入字串。

public:
 override System::Threading::Tasks::Task ^ WriteAsync(char value);

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

[<System.Runtime.InteropServices.ComVisible(false)>]
override this.WriteAsync : char -> System.Threading.Tasks.Task

Public Overrides Function WriteAsync (value As Char) As Task

參數

value: Char

寫入字串的字元。

傳回

Task

一個代表非同步寫入操作的任務。

屬性: ComVisibleAttribute

例外狀況

ObjectDisposedException

弦樂寫字器被處理掉。

InvalidOperationException

字串寫入器目前正被先前的寫入操作使用。

範例

以下範例展示了如何利用此 WriteAsync(Char) 方法書寫字元。

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

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

        static async void WriteCharacters()
        {
            StringBuilder stringToWrite = new StringBuilder("Characters in StringBuilder");
            stringToWrite.AppendLine();

            using (StringWriter writer = new StringWriter(stringToWrite))
            {
                UnicodeEncoding ue = new UnicodeEncoding();
                char[] charsToAdd = ue.GetChars(ue.GetBytes("and chars to add"));
                foreach (char c in charsToAdd)
                {
                    await writer.WriteAsync(c);
                }
                Console.WriteLine(stringToWrite.ToString());
            }
        }
    }
}
// The example displays the following output:
//
// Characters in StringBuilder
// and chars to add
//

Imports System.IO
Imports System.Text

Module Module1

    Sub Main()
        WriteCharacters()
    End Sub

    Async Sub WriteCharacters()
        Dim stringToWrite As StringBuilder = New StringBuilder("Characters in StringBuilder")
        stringToWrite.AppendLine()

        Using writer As StringWriter = New StringWriter(stringToWrite)

            Dim ue As UnicodeEncoding = New UnicodeEncoding()
            Dim charsToAdd() = ue.GetChars(ue.GetBytes("and chars to add"))
            For Each c As Char In charsToAdd
                Await writer.WriteAsync(c)
            Next
            Console.WriteLine(stringToWrite.ToString())
        End Using
    End Sub
End Module
' The example displays the following output:
'
' Characters in StringBuilder
' and chars to add
'

備註

此方法在任務中儲存所有非使用例外，該方法的同步對應程式可拋出這些例外。如果回傳的任務中儲存了例外，該例外會在等待任務時拋出。使用例外錯誤，例如 ArgumentException，仍會同步拋出。關於儲存的例外，請參見由 Write(Char)拋出的例外。

適用於

WriteAsync(String)

非同步地將字串寫入目前的字串。

public:
 override System::Threading::Tasks::Task ^ WriteAsync(System::String ^ value);

public override System.Threading.Tasks.Task WriteAsync(string value);

[System.Runtime.InteropServices.ComVisible(false)]
public override System.Threading.Tasks.Task WriteAsync(string value);

override this.WriteAsync : string -> System.Threading.Tasks.Task

[<System.Runtime.InteropServices.ComVisible(false)>]
override this.WriteAsync : string -> System.Threading.Tasks.Task

Public Overrides Function WriteAsync (value As String) As Task

參數

value: String

要寫入的字串。若 value ， null則文字串流中不會寫入任何資料。

傳回

Task

一個代表非同步寫入操作的任務。

屬性: ComVisibleAttribute

例外狀況

ObjectDisposedException

弦樂寫字器被處理掉。

InvalidOperationException

字串寫入器目前正被先前的寫入操作使用。

範例

以下範例展示了如何利用該 WriteAsync(String) 方法來撰寫字串。

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

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

        static async void WriteCharacters()
        {
            StringBuilder stringToWrite = new StringBuilder("Characters in StringBuilder");
            stringToWrite.AppendLine();

            using (StringWriter writer = new StringWriter(stringToWrite))
            {
                await writer.WriteAsync("and add characters through StringWriter");
                Console.WriteLine(stringToWrite.ToString());
            }
        }
    }
}
// The example displays the following output:
//
// Characters in StringBuilder
// and add characters through StringWriter
//

Imports System.IO
Imports System.Text

Module Module1

    Sub Main()
        WriteCharacters()
    End Sub

    Async Sub WriteCharacters()
        Dim stringToWrite As StringBuilder = New StringBuilder("Characters in StringBuilder")
        stringToWrite.AppendLine()

        Using writer As StringWriter = New StringWriter(stringToWrite)
            Await writer.WriteAsync("and add characters through StringWriter")
            Console.WriteLine(stringToWrite.ToString())
        End Using
    End Sub
End Module
' The example displays the following output:
'
' Characters in StringBuilder
' and add characters through StringWriter
'

備註

此方法在任務中儲存所有非使用例外，該方法的同步對應程式可拋出這些例外。如果回傳的任務中儲存了例外，該例外會在等待任務時拋出。使用例外錯誤，例如 ArgumentException，仍會同步拋出。關於儲存的例外，請參見由 Write(String)拋出的例外。

適用於

WriteAsync(ReadOnlyMemory<Char>, CancellationToken)

非同步地將記憶體區域的字元寫入字串。

public override System.Threading.Tasks.Task WriteAsync(ReadOnlyMemory<char> buffer, System.Threading.CancellationToken cancellationToken = default);

override this.WriteAsync : ReadOnlyMemory<char> * System.Threading.CancellationToken -> System.Threading.Tasks.Task

Public Overrides Function WriteAsync (buffer As ReadOnlyMemory(Of Char), Optional cancellationToken As CancellationToken = Nothing) As Task

參數

buffer: ReadOnlyMemory<Char>

字元記憶體區域，用來寫入字串。

cancellationToken: CancellationToken

用來監控取消申請的代幣。預設值為 None。

傳回

Task

一個代表非同步寫入操作的任務。

例外狀況

OperationCanceledException

取消令牌也被取消了。此例外會儲存在回傳的任務中。

適用於

WriteAsync(Char[], Int32, Int32)

非同步地將一個字元子陣列寫入字串。

public:
 override System::Threading::Tasks::Task ^ WriteAsync(cli::array <char> ^ buffer, int index, int count);

public override System.Threading.Tasks.Task WriteAsync(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

[<System.Runtime.InteropServices.ComVisible(false)>]
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

參數

buffer: Char[]

要從中寫入數據的字元陣列。

index: Int32

緩衝區中開始讀取資料的位置。

count: Int32

要寫入的字元數上限。

傳回

Task

一個代表非同步寫入操作的任務。

屬性: ComVisibleAttribute

例外狀況

ArgumentNullException

buffer 是 null。

ArgumentException

優點indexcount大於緩衝長度。

ArgumentOutOfRangeException

index 或 count 是陰性。

ObjectDisposedException

弦樂寫字器被處理掉。

InvalidOperationException

字串寫入器目前正被先前的寫入操作使用。

範例

以下範例展示了如何利用此 WriteAsync(Char[], Int32, Int32) 方法書寫字元。

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

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

        static async void WriteCharacters()
        {
            StringBuilder stringToWrite = new StringBuilder("Characters in StringBuilder");
            stringToWrite.AppendLine();

            using (StringWriter writer = new StringWriter(stringToWrite))
            {
                UnicodeEncoding ue = new UnicodeEncoding();
                char[] charsToAdd = ue.GetChars(ue.GetBytes("and chars to add"));

                await writer.WriteAsync(charsToAdd, 0, charsToAdd.Length);

                Console.WriteLine(stringToWrite.ToString());
            }
        }
    }
}
// The example displays the following output:
//
// Characters in StringBuilder
// and chars to add
//

Imports System.IO
Imports System.Text

Module Module1

    Sub Main()
        WriteCharacters()
    End Sub

    Async Sub WriteCharacters()
        Dim stringToWrite As StringBuilder = New StringBuilder("Characters in StringBuilder")
        stringToWrite.AppendLine()

        Using writer As StringWriter = New StringWriter(stringToWrite)

            Dim ue As UnicodeEncoding = New UnicodeEncoding()
            Dim charsToAdd() = ue.GetChars(ue.GetBytes("and chars to add"))

            Await writer.WriteAsync(charsToAdd, 0, charsToAdd.Length)

            Console.WriteLine(stringToWrite.ToString())
        End Using
    End Sub
End Module
' The example displays the following output:
'
' Characters in StringBuilder
' and chars to add
'

備註

此方法在任務中儲存所有非使用例外，該方法的同步對應程式可拋出這些例外。如果回傳的任務中儲存了例外，該例外會在等待任務時拋出。使用例外錯誤，例如 ArgumentException，仍會同步拋出。關於儲存的例外，請參見由 Write(Char[], Int32, Int32)拋出的例外。

適用於

意見反應

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