WindowsRuntimeStorageExtensions Classe

Definizione

public ref class WindowsRuntimeStorageExtensions abstract sealed

[System.Security.SecurityCritical]
public static class WindowsRuntimeStorageExtensions

[<System.Security.SecurityCritical>]
type WindowsRuntimeStorageExtensions = class

Public Module WindowsRuntimeStorageExtensions

Ereditarietà

Object

WindowsRuntimeStorageExtensions

Attributi

SecurityCriticalAttribute

Esempio

Nell'esempio seguente viene illustrato come aprire un file nei dati dell'applicazione come Stream in un'app di Windows Store e scriverlo usando un'istanza della StreamWriter classe. Legge quindi il contenuto del file usando un'istanza della StreamReader classe.

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

Nell'esempio successivo viene illustrato il codice XAML associato all'esempio precedente.

<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>

Commenti

Questi metodi di estensione sono disponibili solo quando si sviluppano app di Windows Store. I metodi offrono modi pratici per aprire i file per la lettura o la scrittura nelle app di Windows Store. Non si crea un'istanza della WindowsRuntimeStorageExtensions classe, ma si usano questi metodi da istanze delle IStorageFile interfacce e IStorageFolder .

La WindowsRuntimeStorageExtensions classe contiene due metodi che estendono IStorageFile per la lettura o la scrittura:

• OpenStreamForReadAsync(IStorageFile)
• OpenStreamForWriteAsync(IStorageFile)

La classe WindowsRuntimeStorageExtensions contiene due metodi che estendono IStorageFolder per la lettura e la scrittura:

• OpenStreamForReadAsync(IStorageFolder, String)
• OpenStreamForWriteAsync(IStorageFolder, String, CreationCollisionOption)

Metodi

Si applica a