Windows 8 Store Apps Learning (22) file system: Accessing folders and files, searching local files

File system: Accessing folders and files, searching for local files via Aqs

Introduced

Re-imagine the Windows 8 Store Apps File system

File access-access folders and files, and get various properties of files

Folder Access-some special actions when traversing folders

Thumbnail access-Get a thumbnail of a file

AQS-Search local files via Aqs (Advanced Query Syntax)

Example

1. Demonstrates how to access folders and files, and how to get the various properties of a file

Filesystem/fileaccess.xaml

<page
    x:class= "XamlDemo.FileSystem.FileAccess"
    xmlns= "http://schemas.microsoft.com/winfx/2006/xaml/ Presentation "
    xmlns:x=" Http://schemas.microsoft.com/winfx/2006/xaml "
    xmlns:local=" using: Xamldemo.filesystem "
    xmlns:d=" http://schemas.microsoft.com/expression/blend/2008 "
    xmlns:mc=" http:// schemas.openxmlformats.org/markup-compatibility/2006 "
    mc:ignorable=" D ">
    
    <grid background=" Transparent ">
        <stackpanel margin=" 0 0 0 ">
    
            <textblock name=" lblmsg "fontsize=" 14.667 "/>
             
            <listbox name= "ListBox" width= "height=" selectionchanged= "Listbox_selectionchanged_1" Horizontalalignment= "left" margin= "0 0 0"/>
                
        </StackPanel>
    </Grid>
</Page>

Filesystem/fileaccess.xaml.cs

* * Demonstrates how to access folders and files, and how to get various properties of a file * * Storagefolder-Folder Action class * Get folder-related properties, rename, Create ... * * * storagefile-File Operation class * Get file-related properties, rename, Create ..., take ..., Copy ..., move ..., Delete ..., Open ..., Replace ...
* * Note: The related classes in the WinRT about the storage operations are in the Windows.storage namespace * * using System;
Using System.Collections.Generic;
Using Windows.storage;
Using Windows.Storage.FileProperties;
Using Windows.UI.Xaml;
Using Windows.UI.Xaml.Controls;
Using Windows.UI.Xaml.Navigation;
    
Using System.Linq;
        Namespace Xamldemo.filesystem {public sealed partial class Fileaccess:page {public FileAccess () {this.
        InitializeComponent (); } protected async override void Onnavigatedto (NavigationEventArgs e) {//traverse all top-level in the document library directory
            File (the document library feature needs to be selected in package.appxmanifest) storagefolder storagefolder = knownfolders.documentslibrary; ireadonlylist<storagefile> files = await storagefolder.getfilesasync ();
            Listbox.itemssource = files. Select (P => p.name).
        ToList ();
            Private async void Listbox_selectionchanged_1 (object sender, SelectionChangedEventArgs e) {
            Gets the user-selected file string fileName = (string) Listbox.selecteditem;
            Storagefolder storagefolder = knownfolders.documentslibrary;
    
            Storagefile Storagefile = await storagefolder.getfileasync (fileName);
                Displays various properties of the file if (storagefile!= null) {Lblmsg.text = "Name:" + storagefile.name;
                Lblmsg.text + = Environment.NewLine;
                Lblmsg.text + = "FileType:" + storagefile.filetype;
    
                Lblmsg.text + = Environment.NewLine;
                Basicproperties basicproperties = await storagefile.getbasicpropertiesasync ();
                Lblmsg.text + = "Size:" + basicproperties.size;
                Lblmsg.text + = Environment.NewLine; Lblmsg.text = "DatemoDified: "+ basicproperties.datemodified;
    
                Lblmsg.text + = Environment.NewLine; * * Get various other attributes of the file * Detailed list of attributes see: Http://msdn.microsoft.com/en-us/library/windows/desktop/ff5
                21735 (v=vs.85). aspx */list<string> propertiesname = new list<string> ();
                Propertiesname.add ("system.dateaccessed");
                Propertiesname.add ("system.datecreated");
                Propertiesname.add ("System.fileowner"); idictionary<string, object> extraproperties = await StorageFile.Properties.RetrievePropertiesAsync (
    
                Propertiesname);
                Lblmsg.text + + "system.dateaccessed:" + extraproperties["system.dateaccessed"];
                Lblmsg.text + = Environment.NewLine;
                Lblmsg.text + + "system.datecreated:" + extraproperties["system.datecreated"];
                Lblmsg.text + = Environment.NewLine; Lblmsg.text = "SystEm.
            Fileowner: "+ extraproperties[" System.fileowner "]; }
        }
    }
}

2. Demonstrates some special operations when traversing a folder

Filesystem/folderaccess.xaml

<page
    x:class= "XamlDemo.FileSystem.FolderAccess"
    xmlns= "http://schemas.microsoft.com/winfx/2006/ Xaml/presentation "
    xmlns:x=" Http://schemas.microsoft.com/winfx/2006/xaml "
    xmlns:local=" using: Xamldemo.filesystem "
    xmlns:d=" http://schemas.microsoft.com/expression/blend/2008 "
    xmlns:mc=" http:// schemas.openxmlformats.org/markup-compatibility/2006 "
    mc:ignorable=" D ">
    
    <grid background=" Transparent ">
        <stackpanel margin=" 0 0 0 ">
    
            <textblock name=" lblmsg "fontsize=" 14.667 "/>
    
            <button name= "Btngroupfile" content= "group file" click= "Btngroupfile_click_1" margin= "0 0 0"/>
    
            < Button Name= "Btnprefetchapi" content= "Loading information from Prefetch" click= "btnprefetchapi_click_1" margin= "0 0 0"/>
                
        < /stackpanel>
    </Grid>
</Page>