WindowsRuntimeStreamExtensions.AsStreamForWrite Method (IOutputStream)
.NET Framework (current version)
Converts an output 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)
'Declaration <ExtensionAttribute> _ <CLSCompliantAttribute(False)> _ Public Shared Function AsStreamForWrite ( _ windowsRuntimeStream As IOutputStream _ ) As Stream
Parameters
- windowsRuntimeStream
- Type: IOutputStream
The Windows Runtime IOutputStream object to convert.
Usage Note
In Visual Basic and C#, you can call this method as an instance method on any object of type IOutputStream. 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).| Exception | Condition |
|---|---|
| ArgumentNullException | windowsRuntimeStream is Nothing. |
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.
<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>
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