共用方式為

StorageLibraryChangeTrackerTrigger 類別

  • 參考

定義

命名空間:
Windows.ApplicationModel.Background
編輯

表示 StorageFolder 內的檔案變更，觸發要執行的背景工作。

public ref class StorageLibraryChangeTrackerTrigger sealed : IBackgroundTrigger
/// [Windows.Foundation.Metadata.Activatable(Windows.ApplicationModel.Background.IStorageLibraryChangeTrackerTriggerFactory, 393216, "Windows.Foundation.UniversalApiContract")]
/// [Windows.Foundation.Metadata.ContractVersion(Windows.Foundation.UniversalApiContract, 393216)]
/// [Windows.Foundation.Metadata.MarshalingBehavior(Windows.Foundation.Metadata.MarshalingType.Agile)]
/// [Windows.Foundation.Metadata.Threading(Windows.Foundation.Metadata.ThreadingModel.Both)]
class StorageLibraryChangeTrackerTrigger final : IBackgroundTrigger
[Windows.Foundation.Metadata.Activatable(typeof(Windows.ApplicationModel.Background.IStorageLibraryChangeTrackerTriggerFactory), 393216, "Windows.Foundation.UniversalApiContract")]
[Windows.Foundation.Metadata.ContractVersion(typeof(Windows.Foundation.UniversalApiContract), 393216)]
[Windows.Foundation.Metadata.MarshalingBehavior(Windows.Foundation.Metadata.MarshalingType.Agile)]
[Windows.Foundation.Metadata.Threading(Windows.Foundation.Metadata.ThreadingModel.Both)]
public sealed class StorageLibraryChangeTrackerTrigger : IBackgroundTrigger
function StorageLibraryChangeTrackerTrigger(tracker)
Public NotInheritable Class StorageLibraryChangeTrackerTrigger
Implements IBackgroundTrigger
繼承
Object Platform::Object IInspectable StorageLibraryChangeTrackerTrigger
屬性
ActivatableAttribute ContractVersionAttribute MarshalingBehaviorAttribute ThreadingAttribute
實作
IBackgroundTrigger

Windows 需求

裝置系列
Windows 10, version 1803 (已於 10.0.17134.0 引進)
API contract
Windows.Foundation.UniversalApiContract (已於 v6.0 引進)

範例

下列範例示範如何建立和註冊指定資料夾的儲存程式庫變更觸發程式。

private async Task<bool> RegisterBackgroundTask(StorageFolder folder)
{
    StorageLibraryChangeTracker tracker = folder.TryGetChangeTracker();
    if (tracker != null)
    {
        tracker.Enable();

        StorageLibraryChangeTrackerTrigger trigger = new StorageLibraryChangeTrackerTrigger(tracker);

        string name = "StorageLibraryChangeTrackerTask"; // a friendly task name
        string taskEntryPoint = "Tasks.StorageLibraryChangeTrackerTask";

        var access = await BackgroundExecutionManager.RequestAccessAsync(); // to register background tasks, you must first call RequestAccessAsync()

        BackgroundTaskBuilder builder = new BackgroundTaskBuilder();
        builder.Name = name;
        builder.TaskEntryPoint = taskEntryPoint;
        builder.SetTrigger(trigger);
        BackgroundTaskRegistration task = builder.Register();

        return true;
    }

    // Not getting a tracker means we don't have access to the folder or it’s not a physical folder
    return false;
}

備註

必須先在資訊清單中宣告背景工作，才能成功註冊。

建構函式

StorageLibraryChangeTrackerTrigger(StorageLibraryChangeTracker)

初始化新的 StorageLibraryChangeTrackerTrigger 實例。

適用於

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