WindowsRuntimeStreamExtensions Class

Definition

Namespace:

System.IO

Assembly:

System.Runtime.WindowsRuntime.dll

Contains extension methods for converting between streams in the Windows Runtime and managed streams in the .NET for Windows Store apps.

public ref class WindowsRuntimeStreamExtensions abstract sealed

public static class WindowsRuntimeStreamExtensions

type WindowsRuntimeStreamExtensions = class

Public Module WindowsRuntimeStreamExtensions

Inheritance

Object

WindowsRuntimeStreamExtensions

Examples

The following example shows how to use the AsStreamForWrite and AsStreamForRead

using System;
using System.IO;
using Windows.Storage;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;

namespace ExampleApplication
{
    public sealed partial class BlankPage : Page
    {
        public BlankPage()
        {
            this.InitializeComponent();
        }

        private async void CreateButton_Click(object sender, RoutedEventArgs e)
        {
            StorageFile newFile = await ApplicationData.Current.LocalFolder.CreateFileAsync("testfile.txt");
            var streamNewFile = await newFile.OpenAsync(FileAccessMode.ReadWrite);

            using (var outputNewFile = streamNewFile.GetOutputStreamAt(0))
            {
                using (StreamWriter writer = new StreamWriter(outputNewFile.AsStreamForWrite()))
                {
                    await writer.WriteLineAsync("content for new file");
                    await writer.WriteLineAsync(UserText.Text);
                }
            }
        }

        private async void VerifyButton_Click(object sender, RoutedEventArgs e)
        {
            StorageFile openedFile = await ApplicationData.Current.LocalFolder.GetFileAsync("testfile.txt");
            var streamOpenedFile = await openedFile.OpenAsync(FileAccessMode.Read);

            using (var inputOpenedFile = streamOpenedFile.GetInputStreamAt(0))
            {
                using (StreamReader reader = new StreamReader(inputOpenedFile.AsStreamForRead()))
                {
                    Results.Text = await reader.ReadToEndAsync();
                }
            }
        }
    }
}

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.

<Page
    x:Class="ExampleApplication.BlankPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:ExampleApplication"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d">

    <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>
    </StackPanel>
</Page>

Remarks

These extension methods are available only when you develop Windows Store apps. The methods provide convenient ways of working with streams in Windows Store apps. You do not create an instance of the WindowsRuntimeStreamExtensions class; instead, you use these methods from instances of the IInputStream and IOutputStream interfaces and the Stream class.

The WindowsRuntimeStreamExtensions class contains two methods for converting a managed Stream object to a stream in the Windows Runtime:

• AsInputStream
• AsOutputStream

The WindowsRuntimeStreamExtensions class contains three overloaded methods for converting a stream in the Windows Runtime to a Stream object:

• AsStream
• AsStreamForRead
• AsStreamForWrite

Starting with the .NET Framework 4.5.1, the WindowsRuntimeStreamExtensions class contains a method for converting a stream to a Windows Runtime RandomAccessStream:

• AsRandomAccessStream(Stream)

Methods

AsInputStream(Stream)	Converts a managed stream in the .NET for Windows Store apps to an input stream in the Windows Runtime.
AsOutputStream(Stream)	Converts a managed stream in the .NET for Windows Store apps to an output stream in the Windows Runtime.
AsRandomAccessStream(Stream)	Converts the specified stream to a random access stream.
AsStream(IRandomAccessStream)	Converts a random access stream in the Windows Runtime to a managed stream in the .NET for Windows Store apps.
AsStream(IRandomAccessStream, Int32)	Converts a random access stream in the Windows Runtime to a managed stream in the .NET for Windows Store apps using the specified buffer size.
AsStreamForRead(IInputStream)	Converts an input stream in the Windows Runtime to a managed stream in the .NET for Windows Store apps.
AsStreamForRead(IInputStream, Int32)	Converts an input stream in the Windows Runtime to a managed stream in the .NET for Windows 8.x Store apps using the specified buffer size.
AsStreamForWrite(IOutputStream)	Converts an output stream in the Windows Runtime to a managed stream in the .NET for Windows 8.x Store apps.
AsStreamForWrite(IOutputStream, Int32)	Converts an output stream in the Windows Runtime to a managed stream in the .NET for Windows Store apps using the specified buffer size.