WindowsRuntimeStreamExtensions.AsStreamForWrite 方法

定義

多載

AsStreamForWrite(IOutputStream)

將 Windows 執行階段中的輸出資料流轉換成適用於 Windows 8.x 市集應用程式的 .NET 中的受控資料流。Converts an output stream in the Windows Runtime to a managed stream in the .NET for Windows 8.x Store apps.

AsStreamForWrite(IOutputStream, Int32)

使用指定的緩衝區大小將 Windows 執行階段中的輸出資料流轉換成適用於 Windows 市集應用程式的 .NET 中的受控資料流。Converts an output stream in the Windows Runtime to a managed stream in the .NET for Windows Store apps using the specified buffer size.

AsStreamForWrite(IOutputStream)

重要

此 API 不符合 CLS 規範。

將 Windows 執行階段中的輸出資料流轉換成適用於 Windows 8.x 市集應用程式的 .NET 中的受控資料流。Converts an output stream in the Windows Runtime to a managed stream in the .NET for Windows 8.x Store apps.

public:
[System::Runtime::CompilerServices::Extension]
 static System::IO::Stream ^ AsStreamForWrite(Windows::Storage::Streams::IOutputStream ^ windowsRuntimeStream);
[System.CLSCompliant(false)]
public static System.IO.Stream AsStreamForWrite (this Windows.Storage.Streams.IOutputStream windowsRuntimeStream);
static member AsStreamForWrite : Windows.Storage.Streams.IOutputStream -> System.IO.Stream
<Extension()>
Public Function AsStreamForWrite (windowsRuntimeStream As IOutputStream) As Stream

參數

windowsRuntimeStream
IOutputStream

要轉換的 Windows 執行階段 物件。The Windows Runtime object to convert.

傳回

轉換的資料流。The converted stream.

屬性

例外狀況

windowsRuntimeStreamnullwindowsRuntimeStream is null.

範例

下列範例示範如何使用 AsStreamForWriteAsStreamForRead 方法,將 managed 資料流程轉換成 Windows 執行階段中的資料流程。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.

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

以下是與上一個範例相關聯的 XAML 程式碼。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>

備註

注意

在 Visual Basic 和C#中,您可以在 Stream類型的任何物件上,呼叫這個方法做為實例方法。In Visual Basic and C#, you can call this method as an instance method on any object of type Stream. 使用執行個體方法語法呼叫這個方法時,請省略第一個參數。When you use instance method syntax to call this method, omit the first parameter. 如需詳細資訊,請參閱擴充方法(Visual Basic)擴充C#方法(程式設計手冊)For more information, see Extension Methods (Visual Basic) or Extension Methods (C# Programming Guide).

轉換資料流程時,會使用預設緩衝區大小16384個位元組。A default buffer size of 16,384 bytes is used when converting the stream. 若要指定不同的緩衝區大小,請使用 AsStreamForWrite(IOutputStream, Int32) 多載。To specify a different buffer size, use the AsStreamForWrite(IOutputStream, Int32) overload.

AsStreamForWrite(IOutputStream, Int32)

重要

此 API 不符合 CLS 規範。

使用指定的緩衝區大小將 Windows 執行階段中的輸出資料流轉換成適用於 Windows 市集應用程式的 .NET 中的受控資料流。Converts an output stream in the Windows Runtime to a managed stream in the .NET for Windows Store apps using the specified buffer size.

public:
[System::Runtime::CompilerServices::Extension]
 static System::IO::Stream ^ AsStreamForWrite(Windows::Storage::Streams::IOutputStream ^ windowsRuntimeStream, int bufferSize);
[System.CLSCompliant(false)]
public static System.IO.Stream AsStreamForWrite (this Windows.Storage.Streams.IOutputStream windowsRuntimeStream, int bufferSize);
static member AsStreamForWrite : Windows.Storage.Streams.IOutputStream * int -> System.IO.Stream
<Extension()>
Public Function AsStreamForWrite (windowsRuntimeStream As IOutputStream, bufferSize As Integer) As Stream

參數

windowsRuntimeStream
IOutputStream

要轉換的 Windows 執行階段 IOutputStream 物件。The Windows Runtime IOutputStream object to convert.

bufferSize
Int32

緩衝區的大小 (以位元組為單位)。The size, in bytes, of the buffer. 這個值不可以是負數,但可以是 0 (零),以停用緩衝處理。This value cannot be negative, but it can be 0 (zero) to disable buffering.

傳回

轉換的資料流。The converted stream.

屬性

例外狀況

windowsRuntimeStreamnullwindowsRuntimeStream is null.

bufferSize 為負。bufferSize is negative.

備註

注意

在 Visual Basic 和C#中,您可以在 Stream類型的任何物件上,呼叫這個方法做為實例方法。In Visual Basic and C#, you can call this method as an instance method on any object of type Stream. 使用執行個體方法語法呼叫這個方法時,請省略第一個參數。When you use instance method syntax to call this method, omit the first parameter. 如需詳細資訊,請參閱擴充方法(Visual Basic)擴充C#方法(程式設計手冊)For more information, see Extension Methods (Visual Basic) or Extension Methods (C# Programming Guide).

您可以使用這個方法來指定轉換資料流程時的緩衝區大小。You use this method to specify a buffer size when converting the stream. 若要使用16384位元組的預設緩衝區大小,請使用 AsStreamForWrite(IOutputStream) 多載。To use the default buffer size of 16,384 bytes, use the AsStreamForWrite(IOutputStream) overload.

在大部分的情況下,緩衝處理可改善串流作業的效能。In most situations, buffering improves the performance of stream operations. 您可以藉由將 bufferSize 設定為零來停用緩衝,但只有在確定停用緩衝適用于您的情況時,才應該這麼做。You can disable buffering by setting bufferSize to zero, but you should do this only when you are sure that disabling buffering is appropriate for your situation.

適用於