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StreamWriter.WriteAsync Method (Char)

.NET Framework 4.6 and 4.5

Writes a character to the stream asynchronously.

Namespace:  System.IO
Assemblies:   mscorlib (in mscorlib.dll)
  System.IO (in System.IO.dll)

[ComVisibleAttribute(false)]
[HostProtectionAttribute(SecurityAction.LinkDemand, ExternalThreading = true)]
public override Task WriteAsync(
	char value
)

Parameters

value
Type: System.Char

The character to write to the stream.

Return Value

Type: System.Threading.Tasks.Task
A task that represents the asynchronous write operation.

ExceptionCondition
ObjectDisposedException

The stream writer is disposed.

InvalidOperationException

The stream writer is currently in use by a previous write operation.

NoteNote

The HostProtectionAttribute attribute applied to this type or member has the following Resources property value: ExternalThreading. The HostProtectionAttribute does not affect desktop applications (which are typically started by double-clicking an icon, typing a command, or entering a URL in a browser). For more information, see the HostProtectionAttribute class or SQL Server Programming and Host Protection Attributes.

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');
            }
        }
    }
}

.NET Framework

Supported in: 4.6, 4.5

.NET for Windows Phone apps

Supported in: Windows Phone 8.1, Windows Phone Silverlight 8.1, Windows Phone Silverlight 8
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