共用方式為


WindowsRuntimeStorageExtensions.OpenStreamForWriteAsync 方法

定義

多載

OpenStreamForWriteAsync(IStorageFile)

擷取資料流以寫入特定檔案。

OpenStreamForWriteAsync(IStorageFolder, String, CreationCollisionOption)

擷取資料流以寫入指定上層資料夾中的檔案。

OpenStreamForWriteAsync(IStorageFile)

重要

此 API 不符合 CLS 規範。

擷取資料流以寫入特定檔案。

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
IStorageFile

要寫入到其中的 Windows 執行階段 IStorageFile 物件。

傳回

表示非同步寫入作業的工作。

屬性

例外狀況

windowsRuntimeFilenull

檔案無法開啟,或無法擷取成資料流。

範例

下列範例示範如何在 Windows 市集應用程式中開啟檔案做為 Stream ,並使用 類別的 StreamReader 實例寫入檔案。

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

下一個範例顯示與上一個範例相關聯的 XAML 程式代碼。

<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

注意

在 Visual Basic 和 C# 中,您可以在類型 IStorageFile的任何物件上呼叫這個方法作為實例方法。 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。 如需詳細資訊,請參閱 Visual Basic) (擴充方法 C# 程式設計手冊 (的擴充方法)

適用於

OpenStreamForWriteAsync(IStorageFolder, String, CreationCollisionOption)

重要

此 API 不符合 CLS 規範。

擷取資料流以寫入指定上層資料夾中的檔案。

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
IStorageFolder

包含做為寫入目標檔案的 Windows 執行階段 IStorageFile 物件。

relativePath
String

要寫入之檔案的路徑(相對於根資料夾)。

creationCollisionOption
CreationCollisionOption

Windows 執行階段 CreationCollisionOption 列舉值,會指定當要建立的檔案名稱和現有檔案名稱相同時要使用的行為。

傳回

表示非同步寫入作業的工作。

屬性

例外狀況

rootDirectoryrelativePathnull

relativePath 是空的或僅包含空白字元。

檔案無法開啟,或無法擷取成資料流。

範例

下列範例示範如何在 Windows 市集應用程式中開啟檔案做為 Stream ,並使用 類別的 StreamReader 實例寫入檔案。

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

下一個範例顯示與上一個範例相關聯的 XAML 程式代碼。

<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

注意

在 Visual Basic 和 C# 中,您可以在類型 IStorageFolder的任何物件上呼叫這個方法作為實例方法。 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。 如需詳細資訊,請參閱 Visual Basic) (擴充方法 C# 程式設計手冊 (的擴充方法)

適用於