Enumerare e interrogare file e cartelle

2025-06-10

Accedere a file e cartelle in una cartella, una raccolta, un dispositivo o una posizione di rete. È anche possibile eseguire query su file e cartelle in una posizione costruendo apposite richieste.

Per indicazioni su come archiviare i dati dell'app UWP (Universal Windows Platform), vedi la classe ApplicationData .

Annotazioni

Per un esempio completo, vedere l'esempio di enumerazione della cartella .

Prerequisiti

Informazioni sulla programmazione asincrona per le app UWP (Universal Windows Platform)

Per informazioni su come scrivere app asincrone in C# o Visual Basic, vedere Chiamare API asincrone in C# o Visual Basic. Per informazioni su come scrivere app asincrone in C++/WinRT, consultare Concorrenza e Operazioni Asincrone con C++/WinRT. Per informazioni su come scrivere app asincrone in C++/CX, vedere Programmazione asincrona in C++/CX.
Autorizzazioni di accesso alla posizione

Ad esempio, il codice in questi esempi richiede la funzionalità picturesLibrary , ma la posizione potrebbe richiedere una funzionalità diversa o nessuna funzionalità. Per altre informazioni, vedere Autorizzazioni di accesso ai file.

Enumerare file e cartelle in una posizione

Annotazioni

Ricorda di dichiarare la funzionalità picturesLibrary.

In questo esempio si usa innanzitutto il metodo StorageFolder.GetFilesAsync per ottenere tutti i file nella cartella radice di KnownFolders.PicturesLibrary (non nelle sottocartelle) ed elencare il nome di ogni file. Successivamente, si usa il metodo StorageFolder.GetFoldersAsync per ottenere tutte le sottocartelle in PicturesLibrary ed elencare il nome di ogni sottocartella.

StorageFolder picturesFolder = KnownFolders.PicturesLibrary;
StringBuilder outputText = new StringBuilder();

IReadOnlyList<StorageFile> fileList = await picturesFolder.GetFilesAsync();

outputText.AppendLine("Files:");
foreach (StorageFile file in fileList)
{
    outputText.Append(file.Name + "\n");
}

IReadOnlyList<StorageFolder> folderList = await picturesFolder.GetFoldersAsync();
           
outputText.AppendLine("Folders:");
foreach (StorageFolder folder in folderList)
{
    outputText.Append(folder.DisplayName + "\n");
}

// MainPage.h
// In MainPage.xaml: <TextBlock x:Name="OutputTextBlock"/>
#include <winrt/Windows.Storage.h>
#include <sstream>
...
Windows::Foundation::IAsyncAction ExampleCoroutineAsync()
{
    // Be sure to specify the Pictures Folder capability in your Package.appxmanifest.
    Windows::Storage::StorageFolder picturesFolder{
        Windows::Storage::KnownFolders::PicturesLibrary()
    };

    std::wstringstream outputString;
    outputString << L"Files:" << std::endl;

    for (auto const& file : co_await picturesFolder.GetFilesAsync())
    {
        outputString << file.Name().c_str() << std::endl;
    }

    outputString << L"Folders:" << std::endl;
    for (auto const& folder : co_await picturesFolder.GetFoldersAsync())
    {
        outputString << folder.Name().c_str() << std::endl;
    }

    OutputTextBlock().Text(outputString.str().c_str());
}

#include <ppltasks.h>
#include <string>
#include <memory>

using namespace Windows::Storage;
using namespace Platform::Collections;
using namespace concurrency;
using namespace std;

// Be sure to specify the Pictures Folder capability in the appxmanifext file.
StorageFolder^ picturesFolder = KnownFolders::PicturesLibrary;

// Use a shared_ptr so that the string stays in memory
// until the last task is complete.
auto outputString = make_shared<wstring>();
*outputString += L"Files:\n";

// Get a read-only vector of the file objects
// and pass it to the continuation.
create_task(picturesFolder->GetFilesAsync())        
   // outputString is captured by value, which creates a copy
   // of the shared_ptr and increments its reference count.
   .then ([outputString] (IVectorView\<StorageFile^>^ files)
   {        
       for ( unsigned int i = 0 ; i < files->Size; i++)
       {
           *outputString += files->GetAt(i)->Name->Data();
           *outputString += L"\n";
      }
   })
   // We need to explicitly state the return type
   // here: -IAsyncOperation<...>
   .then([picturesFolder]() -IAsyncOperation\<IVectorView\<StorageFolder^>^>^
   {
       return picturesFolder->GetFoldersAsync();
   })
   // Capture "this" to access m_OutputTextBlock from within the lambda.
   .then([this, outputString](IVectorView/<StorageFolder^>^ folders)
   {        
       *outputString += L"Folders:\n";

       for ( unsigned int i = 0; i < folders->Size; i++)
       {
          *outputString += folders->GetAt(i)->Name->Data();
          *outputString += L"\n";
       }

       // Assume m_OutputTextBlock is a TextBlock defined in the XAML.
       m_OutputTextBlock->Text = ref new String((*outputString).c_str());
    });

Dim picturesFolder As StorageFolder = KnownFolders.PicturesLibrary
Dim outputText As New StringBuilder

Dim fileList As IReadOnlyList(Of StorageFile) =
    Await picturesFolder.GetFilesAsync()

outputText.AppendLine("Files:")
For Each file As StorageFile In fileList

    outputText.Append(file.Name & vbLf)

Next file

Dim folderList As IReadOnlyList(Of StorageFolder) =
    Await picturesFolder.GetFoldersAsync()

outputText.AppendLine("Folders:")
For Each folder As StorageFolder In folderList

    outputText.Append(folder.DisplayName & vbLf)

Next folder

Annotazioni

In C# o Visual Basic, ricordarsi di inserire la parola chiave async nella dichiarazione di qualsiasi metodo in cui si usa l'operatore await.

In alternativa, è possibile usare il metodo StorageFolder.GetItemsAsync per ottenere tutti gli elementi (file e sottocartelle) in una determinata posizione. Nell'esempio seguente viene utilizzato il metodo GetItemsAsync per ottenere tutti i file e le sottocartelle nella cartella radice di KnownFolders.PicturesLibrary (non nelle sottocartelle). Nell'esempio viene quindi elencato il nome di ogni file e sottocartella. Se l'elemento è una sottocartella, l'esempio aggiunge "folder" al nome.

StorageFolder picturesFolder = KnownFolders.PicturesLibrary;
StringBuilder outputText = new StringBuilder();

IReadOnlyList<IStorageItem> itemsList = await picturesFolder.GetItemsAsync();

foreach (var item in itemsList)
{
    if (item is StorageFolder)
    {
        outputText.Append(item.Name + " folder\n");

    }
    else
    {
        outputText.Append(item.Name + "\n");
    }
}

// MainPage.h
// In MainPage.xaml: <TextBlock x:Name="OutputTextBlock"/>
#include <winrt/Windows.Storage.h>
#include <sstream>
...
Windows::Foundation::IAsyncAction ExampleCoroutineAsync()
{
    // Be sure to specify the Pictures Folder capability in your Package.appxmanifest.
    Windows::Storage::StorageFolder picturesFolder{
        Windows::Storage::KnownFolders::PicturesLibrary()
    };

    std::wstringstream outputString;

    for (Windows::Storage::IStorageItem const& item : co_await picturesFolder.GetItemsAsync())
    {
        outputString << item.Name().c_str();

        if (item.IsOfType(Windows::Storage::StorageItemTypes::Folder))
        {
            outputString << L" folder" << std::endl;
        }
        else
        {
            outputString << std::endl;
        }

        OutputTextBlock().Text(outputString.str().c_str());
    }
}

// See previous example for comments, namespace and #include info.
StorageFolder^ picturesFolder = KnownFolders::PicturesLibrary;
auto outputString = make_shared<wstring>();

create_task(picturesFolder->GetItemsAsync())        
    .then ([this, outputString] (IVectorView<IStorageItem^>^ items)
{        
    for ( unsigned int i = 0 ; i < items->Size; i++)
    {
        *outputString += items->GetAt(i)->Name->Data();
        if(items->GetAt(i)->IsOfType(StorageItemTypes::Folder))
        {
            *outputString += L"  folder\n";
        }
        else
        {
            *outputString += L"\n";
        }
        m_OutputTextBlock->Text = ref new String((*outputString).c_str());
    }
});

Dim picturesFolder As StorageFolder = KnownFolders.PicturesLibrary
Dim outputText As New StringBuilder

Dim itemsList As IReadOnlyList(Of IStorageItem) =
    Await picturesFolder.GetItemsAsync()

For Each item In itemsList

    If TypeOf item Is StorageFolder Then

        outputText.Append(item.Name & " folder" & vbLf)

    Else

        outputText.Append(item.Name & vbLf)

    End If

Next item

Interrogare i file in un percorso ed elencare i file corrispondenti

In questo esempio viene eseguita una query per tutti i file nell'KnownFolders.PicturesLibrary raggruppati per mese e questa volta l'esempio si ripete in sottocartelle. Prima di tutto, chiamiamo StorageFolder.CreateFolderQuery e passiamo il valore CommonFolderQuery.GroupByMonth al metodo . In questo modo si ottiene un oggetto StorageFolderQueryResult.

Successivamente chiamiamo StorageFolderQueryResult.GetFoldersAsync che restituisce gli oggetti StorageFolder che rappresentano le cartelle virtuali. In questo caso si sta raggruppando per mese, quindi le cartelle virtuali rappresentano un gruppo di file con lo stesso mese.

StorageFolder picturesFolder = KnownFolders.PicturesLibrary;

StorageFolderQueryResult queryResult =
    picturesFolder.CreateFolderQuery(CommonFolderQuery.GroupByMonth);
        
IReadOnlyList<StorageFolder> folderList =
    await queryResult.GetFoldersAsync();

StringBuilder outputText = new StringBuilder();

foreach (StorageFolder folder in folderList)
{
    IReadOnlyList<StorageFile> fileList = await folder.GetFilesAsync();

    // Print the month and number of files in this group.
    outputText.AppendLine(folder.Name + " (" + fileList.Count + ")");

    foreach (StorageFile file in fileList)
    {
        // Print the name of the file.
        outputText.AppendLine("   " + file.Name);
    }
}

// MainPage.h
// In MainPage.xaml: <TextBlock x:Name="OutputTextBlock"/>
#include <winrt/Windows.Storage.h>
#include <winrt/Windows.Storage.Search.h>
#include <sstream>
...
Windows::Foundation::IAsyncAction ExampleCoroutineAsync()
{
    // Be sure to specify the Pictures Folder capability in your Package.appxmanifest.
    Windows::Storage::StorageFolder picturesFolder{
        Windows::Storage::KnownFolders::PicturesLibrary()
    };

    Windows::Storage::Search::StorageFolderQueryResult queryResult{
        picturesFolder.CreateFolderQuery(Windows::Storage::Search::CommonFolderQuery::GroupByMonth)
    };

    std::wstringstream outputString;

    for (Windows::Storage::StorageFolder const& folder : co_await queryResult.GetFoldersAsync())
    {
        auto files{ co_await folder.GetFilesAsync() };
        outputString << folder.Name().c_str() << L" (" << files.Size() << L")" << std::endl;

        for (Windows::Storage::StorageFile const& file : files)
        {
            outputString << L"    " << file.Name().c_str() << std::endl;
        }
    }

    OutputTextBlock().Text(outputString.str().c_str());
}

#include <ppltasks.h>
#include <string>
#include <memory>
using namespace Windows::Storage;
using namespace Windows::Storage::Search;
using namespace concurrency;
using namespace Platform::Collections;
using namespace Windows::Foundation::Collections;
using namespace std;

StorageFolder^ picturesFolder = KnownFolders::PicturesLibrary;

StorageFolderQueryResult^ queryResult =
    picturesFolder->CreateFolderQuery(CommonFolderQuery::GroupByMonth);

// Use shared_ptr so that outputString remains in memory
// until the task completes, which is after the function goes out of scope.
auto outputString = std::make_shared<wstring>();

create_task( queryResult->GetFoldersAsync()).then([this, outputString] (IVectorView<StorageFolder^>^ view)
{        
    for ( unsigned int i = 0; i < view->Size; i++)
    {
        create_task(view->GetAt(i)->GetFilesAsync()).then([this, i, view, outputString](IVectorView<StorageFile^>^ files)
        {
            *outputString += view->GetAt(i)->Name->Data();
            *outputString += L" (";
            *outputString += to_wstring(files->Size);
            *outputString += L")\r\n";
            for (unsigned int j = 0; j < files->Size; j++)
            {
                *outputString += L"     ";
                *outputString += files->GetAt(j)->Name->Data();
                *outputString += L"\r\n";
            }
        }).then([this, outputString]()
        {
            m_OutputTextBlock->Text = ref new String((*outputString).c_str());
        });
    }    
});

Dim picturesFolder As StorageFolder = KnownFolders.PicturesLibrary
Dim outputText As New StringBuilder

Dim queryResult As StorageFolderQueryResult =
    picturesFolder.CreateFolderQuery(CommonFolderQuery.GroupByMonth)

Dim folderList As IReadOnlyList(Of StorageFolder) =
    Await queryResult.GetFoldersAsync()

For Each folder As StorageFolder In folderList

    Dim fileList As IReadOnlyList(Of StorageFile) =
        Await folder.GetFilesAsync()

    ' Print the month and number of files in this group.
    outputText.AppendLine(folder.Name & " (" & fileList.Count & ")")

    For Each file As StorageFile In fileList

        ' Print the name of the file.
        outputText.AppendLine("   " & file.Name)

    Next file

Next folder

L'output dell'esempio è simile al seguente.

July ‎2015 (2)
   MyImage3.png
   MyImage4.png
‎December ‎2014 (2)
   MyImage1.png
   MyImage2.png

Condividi tramite

Enumerare e interrogare file e cartelle

Prerequisiti

Enumerare file e cartelle in una posizione

Interrogare i file in un percorso ed elencare i file corrispondenti

Commenti e suggerimenti

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