WindowsRuntimeStorageExtensions.OpenStreamForWriteAsync 方法

定義

命名空間:: System.IO

組件:: System.Runtime.WindowsRuntime.dll

重要

部分資訊涉及發行前產品，在發行之前可能會有大幅修改。 Microsoft 對此處提供的資訊，不做任何明確或隱含的瑕疵擔保。

多載

名稱	Description
OpenStreamForWriteAsync(IStorageFile)	擷取串流以寫入指定檔案。
OpenStreamForWriteAsync(IStorageFolder, String, CreationCollisionOption)	擷取串流，用於寫入指定父資料夾中的檔案。

OpenStreamForWriteAsync(IStorageFile)

重要

此 API 不符合 CLS 規範。

擷取串流以寫入指定檔案。

public:
[System::Runtime::CompilerServices::Extension]
 static System::Threading::Tasks::Task<System::IO::Stream ^> ^ OpenStreamForWriteAsync(Windows::Storage::IStorageFile ^ windowsRuntimeFile);

[System.CLSCompliant(false)]
public static System.Threading.Tasks.Task<System.IO.Stream> OpenStreamForWriteAsync(this Windows.Storage.IStorageFile windowsRuntimeFile);

[<System.CLSCompliant(false)>]
static member OpenStreamForWriteAsync : Windows.Storage.IStorageFile -> System.Threading.Tasks.Task<System.IO.Stream>

<Extension()>
Public Function OpenStreamForWriteAsync (windowsRuntimeFile As IStorageFile) As Task(Of Stream)

參數

windowsRuntimeFile: Windows.Storage.IStorageFile

Windows 執行階段 Windows.Storage.IStorageFile 物件要寫入。

傳回

Task<Stream>

一個代表非同步寫入操作的任務。

屬性: CLSCompliantAttribute

例外狀況

ArgumentNullException

windowsRuntimeFile 是 null。

IOException

該檔案無法以串流方式開啟或取回。

範例

以下範例展示了如何在 Windows Store 應用程式中以 Stream 開啟檔案，並透過 StreamReader 類別的實例來寫入。

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("testfile3.txt");

            using (StreamWriter writer = new StreamWriter(await newFile.OpenStreamForWriteAsync()))
            {
                await writer.WriteLineAsync("new entry");
                await writer.WriteLineAsync(UserText.Text);
            }
        }

        private async void VerifyButton_Click(object sender, RoutedEventArgs e)
        {
            StorageFile openedFile = await ApplicationData.Current.LocalFolder.GetFileAsync("testfile3.txt");
            using (StreamReader reader = new StreamReader(await openedFile.OpenStreamForReadAsync()))
            {
                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("testfile4.txt")

        Using writer As StreamWriter = New StreamWriter(Await newFile.OpenStreamForWriteAsync())
            Await writer.WriteLineAsync("new entry")
            Await writer.WriteLineAsync(UserText.Text)
        End Using
    End Sub

    Private Async Sub VerifyButton_Click(sender As Object, e As RoutedEventArgs)
        Dim openedFile As StorageFile = Await ApplicationData.Current.LocalFolder.GetFileAsync("testfile4.txt")
        Using reader As StreamReader = New StreamReader(Await openedFile.OpenStreamForReadAsync())
            Results.Text = Await reader.ReadToEndAsync()
        End Using
    End Sub
End Class

下一個範例展示了與前一個範例相關的 XAML 程式碼。

<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

Note

在 Visual Basic 和 C# 中，你可以將此方法作為實例方法呼叫，適用於任何類型為 <xref:Windows.Storage.IStorageFile> 的物件。當你使用 instance method 語法呼叫這個方法時，請省略第一個參數。欲了解更多資訊，請參閱 Extension Methods （Visual Basic）或 Extension Methods （C# 程式設計指南）。

適用於

OpenStreamForWriteAsync(IStorageFolder, String, CreationCollisionOption)

重要

此 API 不符合 CLS 規範。

擷取串流，用於寫入指定父資料夾中的檔案。

public:
[System::Runtime::CompilerServices::Extension]
 static System::Threading::Tasks::Task<System::IO::Stream ^> ^ OpenStreamForWriteAsync(Windows::Storage::IStorageFolder ^ rootDirectory, System::String ^ relativePath, Windows::Storage::CreationCollisionOption creationCollisionOption);

[System.CLSCompliant(false)]
public static System.Threading.Tasks.Task<System.IO.Stream> OpenStreamForWriteAsync(this Windows.Storage.IStorageFolder rootDirectory, string relativePath, Windows.Storage.CreationCollisionOption creationCollisionOption);

[<System.CLSCompliant(false)>]
static member OpenStreamForWriteAsync : Windows.Storage.IStorageFolder * string * Windows.Storage.CreationCollisionOption -> System.Threading.Tasks.Task<System.IO.Stream>

<Extension()>
Public Function OpenStreamForWriteAsync (rootDirectory As IStorageFolder, relativePath As String, creationCollisionOption As CreationCollisionOption) As Task(Of Stream)

參數

rootDirectory: Windows.Storage.IStorageFolder

Windows 執行階段 Windows.Storage.IStorageFile 物件，包含要寫入的檔案。

relativePath: String

相對於根資料夾的路徑，指向要寫入的檔案。

creationCollisionOption: Windows.Storage.CreationCollisionOption

當要建立的檔案名稱與現有檔案名稱相同時，Windows 執行階段 Windows.Storage.CreationCollisionOption 枚舉值，該值指定應使用的行為。

傳回

Task<Stream>

一個代表非同步寫入操作的任務。

屬性: CLSCompliantAttribute

例外狀況

ArgumentNullException

rootDirectory 或 relativePath 為 null。

ArgumentException

relativePath 是空的或僅包含空白字元。

IOException

該檔案無法以串流方式開啟或取回。

範例

以下範例展示了如何在 Windows Store 應用程式中以 Stream 開啟檔案，並透過 StreamReader 類別的實例來寫入。

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)
        {
            using (StreamWriter writer =
                new StreamWriter(await ApplicationData.Current.LocalFolder.OpenStreamForWriteAsync(
                "testfile.txt",  CreationCollisionOption.OpenIfExists)))
            {
                await writer.WriteLineAsync("new entry");
                await writer.WriteLineAsync(UserText.Text);
            }
        }

        private async void VerifyButton_Click(object sender, RoutedEventArgs e)
        {
            StorageFile openedFile = await ApplicationData.Current.LocalFolder.GetFileAsync("testfile.txt");
            using (StreamReader reader = new StreamReader(await openedFile.OpenStreamForReadAsync()))
            {
                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)
        Using writer As StreamWriter =
               New StreamWriter(Await ApplicationData.Current.LocalFolder.OpenStreamForWriteAsync(
               "testfile.txt", CreationCollisionOption.OpenIfExists))
            Await writer.WriteLineAsync("new entry")
            Await writer.WriteLineAsync(UserText.Text)
        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")
        Using reader As StreamReader = New StreamReader(Await openedFile.OpenStreamForReadAsync())
            Results.Text = Await reader.ReadToEndAsync()
        End Using
    End Sub
End Class

下一個範例展示了與前一個範例相關的 XAML 程式碼。

<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

Note

在 Visual Basic 和 C# 中，你可以將此方法作為實例方法呼叫，適用於任何類型為 <xref:Windows.Storage.IStorageFolder> 的物件。當你使用 instance method 語法呼叫這個方法時，請省略第一個參數。欲了解更多資訊，請參閱 Extension Methods （Visual Basic）或 Extension Methods （C# 程式設計指南）。

適用於

意見反應

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