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

.NET Framework 4.5

Writes a subarray of characters followed by a line terminator asynchronously to the stream.

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

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

Parameters

buffer
Type: System.Char[]

The character array to write data from.

index
Type: System.Int32

The character position in the buffer at which to start 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.

ExceptionCondition
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 line terminator is defined by the TextWriter.NewLine property.

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 characters to two separate lines in a text file by using the WriteLineAsync(Char[], Int32, Int32) method. The first line contains the first 11 characters from the string (the letters "First line" followed by a space). The second line contains the remaining characters from the string (the letters "and second line").

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("First line and second line"));
            using (StreamWriter writer = File.CreateText("newfile.txt"))
            {
                await writer.WriteLineAsync(charsToAdd, 0, 11);
                await writer.WriteLineAsync(charsToAdd, 11, charsToAdd.Length - 11);
            }
        }
    }
}

.NET Framework

Supported in: 4.5

.NET for Windows Store apps

Supported in: Windows 8

.NET for Windows Phone apps

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

Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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