WindowsRuntimeStreamExtensions.AsStreamForRead Method (IInputStream)

.NET Framework (current version)

Converts an input stream in the Windows Runtime to a managed stream in the .NET for Windows 8.x Store apps.

This API is not CLS-compliant. 

Namespace:  System.IO
Assembly:  System.Runtime.WindowsRuntime (in System.Runtime.WindowsRuntime.dll)

<ExtensionAttribute> _
<CLSCompliantAttribute(False)> _
Public Shared Function AsStreamForRead ( _
	windowsRuntimeStream As IInputStream _
) As Stream


Type: IInputStream

The Windows Runtime IInputStream object to convert.

Return Value

Type: System.IO.Stream
The converted stream.

Usage Note

In Visual Basic and C#, you can call this method as an instance method on any object of type IInputStream. When you use instance method syntax to call this method, omit the first parameter. For more information, see Extension Methods (Visual Basic) or Extension Methods (C# Programming Guide).


windowsRuntimeStream is Nothing.

A default buffer size of 16,384 bytes is used when converting the stream. To specify a different buffer size, use the AsStreamForRead(IInputStream, Int32) overload.

The following example shows how to use the AsStreamForWrite and AsStreamForRead methods to convert a managed stream to and from a stream in the Windows Runtime.

Imports System.IO
Imports Windows.Storage

NotInheritable Public Class BlankPage
    Inherits Page

    Private Async Sub CreateButton_Click(sender As Object, e As RoutedEventArgs)
        Dim newFile As StorageFile = Await ApplicationData.Current.LocalFolder.CreateFileAsync("testfile.txt")
        Dim streamNewFile = Await newFile.OpenAsync(FileAccessMode.ReadWrite)

        Using outputNewFile = streamNewFile.GetOutputStreamAt(0)
            Using writer As StreamWriter = New StreamWriter(outputNewFile.AsStreamForWrite())
                Await writer.WriteLineAsync("content for new file")
                Await writer.WriteLineAsync(UserText.Text)
            End Using 
        End Using 
    End Sub 

    Private Async Sub VerifyButton_Click(sender As Object, e As RoutedEventArgs)
        Dim openedFile As StorageFile = Await ApplicationData.Current.LocalFolder.GetFileAsync("testfile.txt")
        Dim streamOpenedFile = Await openedFile.OpenAsync(FileAccessMode.Read)

        Using inputOpenedFile = streamOpenedFile.GetInputStreamAt(0)

            Using reader As StreamReader = New StreamReader(inputOpenedFile.AsStreamForRead())
                Results.Text = Await reader.ReadToEndAsync()
            End Using 
        End Using 
    End Sub 
End Class

Here's the XAML code that is associated with the previous example.


    <StackPanel Background="{StaticResource ApplicationPageBackgroundBrush}" VerticalAlignment="Center" HorizontalAlignment="Center">
        <TextBlock Text="Provide text to write to file:"></TextBlock>
        <TextBox Name="UserText" Width="400"></TextBox>
        <Button Name="CreateButton" Content="Create File" Click="CreateButton_Click"></Button>
        <Button Name="VerifyButton" Content="Verify Contents" Click="VerifyButton_Click"></Button>
        <TextBlock Name="Results"></TextBlock>

.NET Framework

Supported in: 4.6, 4.5

.NET for Windows Phone apps

Supported in: Windows Phone Silverlight 8