ファイルとフォルダーの列挙と照会Enumerate and query files and folders

フォルダー、ライブラリ、デバイス、またはネットワークの場所にあるファイルやフォルダーにアクセスします。Access files and folders in either a folder, library, device, or network location. ファイルやフォルダーのクエリを作成することで、任意の場所にあるファイルやフォルダーを照会することもできます。You can also query the files and folders in a location by constructing file and folder queries.

ユニバーサル Windows プラットフォーム アプリのデータを保存する方法について詳しくは、ApplicationData クラスをご覧ください。For guidance on how to store your Universal Windows Platform app's data, see the ApplicationData class.

注意

 完全なサンプルについては、「Folder enumeration sample」 (フォルダーの列挙のサンプル) をご覧ください。 For a complete sample, see the Folder enumeration sample.

前提条件Prerequisites

ある場所のファイルやフォルダーを列挙するEnumerate files and folders in a location

注意

 必ず picturesLibrary 機能を宣言してください。 Remember to declare the picturesLibrary capability.

この例では、まず StorageFolder.GetFilesAsync メソッドを使って KnownFolders.PicturesLibrary 内のルート フォルダー (サブフォルダーは除く) にあるすべてのファイルを取得し、各ファイルの名前を一覧表示します。In this example we first use the StorageFolder.GetFilesAsync method to get all the files in the root folder of the KnownFolders.PicturesLibrary (not in subfolders) and list the name of each file. 次に、StorageFolder.GetFoldersAsync メソッドを使って PicturesLibrary 内のすべてのサブフォルダーを取得し、各サブフォルダーの名前を一覧表示します。Next, we use the StorageFolder.GetFoldersAsync method to get all the subfolders in the PicturesLibrary and list the name of each subfolder.

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

注意

C# または Visual Basic では、await 演算子を使うすべてのメソッドのメソッド宣言で、必ず async キーワードを使ってください。In C# or Visual Basic, remember to put the async keyword in the method declaration of any method in which you use the await operator.

または、StorageFolder.GetItemsAsync メソッドを使って、特定の場所にあるすべての項目 (ファイルとサブフォルダーの両方) を取得することもできます。Alternatively, you can use the StorageFolder.GetItemsAsync method to get all items (both files and subfolders) in a particular location. 次の例では、GetItemsAsync メソッドを使って KnownFolders.PicturesLibrary 内のルート フォルダー (サブフォルダーは除く) にあるすべてのファイルとサブフォルダーを取得します。The following example uses the GetItemsAsync method to get all files and subfolders in the root folder of the KnownFolders.PicturesLibrary (not in subfolders). その後、各ファイルとサブフォルダーの名前を一覧表示します。Then the example lists the name of each file and subfolder. 項目がサブフォルダーの場合は、名前に "folder" を追加します。If the item is a subfolder, the example appends "folder" to the name.

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

ある場所に保存されているファイルを照会して、一致するファイルを列挙するQuery files in a location and enumerate matching files

この例では KnownFolders.PicturesLibrary にある月ごとにグループ化されたすべてのファイルにクエリを実行し、今回はサブフォルダーに再帰的に呼び出します。In this example we query for all the files in the KnownFolders.PicturesLibrary grouped by the month, and this time the example recurses into subfolders. まず、StorageFolder.CreateFolderQuery を呼び出し、CommonFolderQuery.GroupByMonth の値をメソッドに渡します。First, we call StorageFolder.CreateFolderQuery and pass the CommonFolderQuery.GroupByMonth value to the method. これで、StorageFolderQueryResult オブジェクトが取得されます。That gives us a StorageFolderQueryResult object.

次に、仮想フォルダーを表す StorageFolder のオブジェクトを返す StorageFolderQueryResult.GetFoldersAsync を呼び出します。Next we call StorageFolderQueryResult.GetFoldersAsync which returns StorageFolder objects representing virtual folders. ここでは月でグループ化されているため、各仮想フォルダーは同じ月にあるファイルのグループを表します。In this case we're grouping by month, so the virtual folders each represent a group of files with the same month.

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

この例の出力は次のようになります。The output of the example looks similar to the following.

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