StreamWriter.WriteAsync Method (Char[], Int32, Int32)

.NET Framework (current version)
 

Writes a subarray of characters to the stream asynchronously.

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

[ComVisibleAttribute(false)]
[HostProtectionAttribute(SecurityAction.LinkDemand, ExternalThreading = true)]
public override Task WriteAsync(
	char[] buffer,
	int index,
	int count
)

Parameters

buffer
Type: System.Char[]

A character array that contains the data to write.

index
Type: System.Int32

The character position in the buffer at which to begin reading data.

count
Type: System.Int32

The maximum number of characters to write.

Return Value

Type: System.Threading.Tasks.Task

A task that represents the asynchronous write operation.

Exception Condition
ArgumentNullException

buffer is null.

ArgumentException

The index plus count is greater than the buffer length.

ArgumentOutOfRangeException

index or count is negative.

ObjectDisposedException

The stream writer is disposed.

InvalidOperationException

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

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);
            }
        }
    }
}

Universal Windows Platform
Available since 8
.NET Framework
Available since 4.5
Portable Class Library
Supported in: portable .NET platforms
Windows Phone Silverlight
Available since 8.0
Windows Phone
Available since 8.1
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