StreamWriter.WriteLineAsync Method

Definition

Overloads

WriteLineAsync()

Writes a line terminator asynchronously to the stream.

WriteLineAsync(Char)

Writes a character followed by a line terminator asynchronously to the stream.

WriteLineAsync(String)

Writes a string followed by a line terminator asynchronously to the stream.

WriteLineAsync(Char[], Int32, Int32)

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

WriteLineAsync()

Writes a line terminator asynchronously to the stream.

[System.Runtime.InteropServices.ComVisible(false)]
public override System.Threading.Tasks.Task WriteLineAsync ();
Returns

A task that represents the asynchronous write operation.

Exceptions

The stream writer is disposed.

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

Remarks

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

WriteLineAsync(Char)

Writes a character followed by a line terminator asynchronously to the stream.

[System.Runtime.InteropServices.ComVisible(false)]
public override System.Threading.Tasks.Task WriteLineAsync (char value);
Parameters
value
Char

The character to write to the stream.

Returns

A task that represents the asynchronous write operation.

Exceptions

The stream writer is disposed.

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

Examples

The following example shows how to write a single character (the letter "a") to a line in a text file, followed by another line that contains a single character (the letter "b"), by using the WriteLineAsync(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.WriteLineAsync('a');
                await writer.WriteLineAsync('b');
            }
        }
    }
}
Imports System.IO
Imports System.Text

Module Module1

    Sub Main()
        WriteCharacters()
    End Sub

    Async Sub WriteCharacters()
        Dim firstChar As Char = "a"
        Dim secondChar As Char = "b"
        Using writer As StreamWriter = File.CreateText("newfile.txt")
            Await writer.WriteLineAsync(firstChar)
            Await writer.WriteLineAsync(secondChar)
        End Using
    End Sub
End Module

Remarks

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

WriteLineAsync(String)

Writes a string followed by a line terminator asynchronously to the stream.

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

The string to write. If the value is null, only a line terminator is written.

Returns

A task that represents the asynchronous write operation.

Exceptions

The stream writer is disposed.

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

Examples

The following example shows how to write two lines that consist of string values to a text file by using the WriteLineAsync(String) 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.WriteLineAsync("First line of example");
                await writer.WriteLineAsync("and second line");
            }
        }
    }
}
Imports System.IO
Imports System.Text

Module Module1

    Sub Main()
        WriteCharacters()
    End Sub

    Async Sub WriteCharacters()
        Using writer As StreamWriter = File.CreateText("newfile.txt")
            Await writer.WriteLineAsync("First line of example")
            Await writer.WriteLineAsync("and second line")
        End Using
    End Sub
End Module

Remarks

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

WriteLineAsync(Char[], Int32, Int32)

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

[System.Runtime.InteropServices.ComVisible(false)]
public override System.Threading.Tasks.Task WriteLineAsync (char[] buffer, int index, int count);
Parameters
buffer
Char[]

The character array to write data from.

index
Int32

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

count
Int32

The maximum number of characters to write.

Returns

A task that represents the asynchronous write operation.

Exceptions

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.

Examples

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);
            }
        }
    }
}
Imports System.IO
Imports System.Text

Module Module1

    Sub Main()
        WriteCharacters()
    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

Remarks

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