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StringReader.ReadLineAsync Method

.NET Framework 4.6 and 4.5

Reads a line of characters asynchronously from the current string and returns the data as a string.

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

'Declaration
<ComVisibleAttribute(False)> _
Public Overrides Function ReadLineAsync As Task(Of String)

Return Value

Type: System.Threading.Tasks.Task(Of String)
A task that represents the asynchronous read operation. The value of the TResult parameter contains the next line from the string reader, or is Nothing if all the characters have been read.

ExceptionCondition
ArgumentOutOfRangeException

The number of characters in the next line is larger than MaxValue.

ObjectDisposedException

The string reader has been disposed.

InvalidOperationException

The reader is currently in use by a previous read operation.

The following example shows how to read one line at a time from a string asynchronously.

Imports System.IO
Imports System.Text

Module Module1

    Sub Main()
        ReadCharacters()
    End Sub

    Async Sub ReadCharacters()
        Dim stringToRead = New StringBuilder()
        stringToRead.AppendLine("Characters in 1st line to read")
        stringToRead.AppendLine("and 2nd line")
        stringToRead.AppendLine("and the end")

        Using reader As StringReader = New StringReader(stringToRead.ToString())
            Dim readText As String = Await reader.ReadLineAsync()
            While Not IsNothing(readText)
                Console.WriteLine(readText)
                readText = Await reader.ReadLineAsync()
            End While 
        End Using 
    End Sub 
End Module 
' The example displays the following output: 

' Characters in 1st line to read 
' and 2nd line 
' and the end 
'

.NET Framework

Supported in: 4.6, 4.5

Supported in: Windows Phone 8.1

Supported in: Windows Phone Silverlight 8.1

Supported in: Windows Phone Silverlight 8
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