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

.NET Framework (current version)

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

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

<HostProtectionAttribute(SecurityAction.LinkDemand, ExternalThreading := True)>
Public Overrides Function WriteLineAsync (
	buffer As Char(),
	index As Integer,
	count As Integer
) As Task


Type: System.Char()

The character array to write data from.

Type: System.Int32

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

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

buffer is null.


The index plus count is greater than the buffer length.


index or count is negative.


The stream writer is disposed.


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

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

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").

Imports System.IO
Imports System.Text

Module Module1

    Sub Main()
    End Sub

    Async Sub WriteCharacters()
        Dim ue As UnicodeEncoding = New UnicodeEncoding()
        Dim charsToAdd() = ue.GetChars(ue.GetBytes("First line and second line"))

        Using writer As StreamWriter = File.CreateText("newfile.txt")
            Await writer.WriteLineAsync(charsToAdd, 0, 11)
            Await writer.WriteLineAsync(charsToAdd, 11, charsToAdd.Length - 11)
        End Using
    End Sub
End Module

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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