共用方式為


DisplayRequest 類別

定義

表示顯示要求。

public ref class DisplayRequest sealed
/// [Windows.Foundation.Metadata.Activatable(65536, Windows.Foundation.UniversalApiContract)]
/// [Windows.Foundation.Metadata.ContractVersion(Windows.Foundation.UniversalApiContract, 65536)]
/// [Windows.Foundation.Metadata.MarshalingBehavior(Windows.Foundation.Metadata.MarshalingType.None)]
/// [Windows.Foundation.Metadata.Threading(Windows.Foundation.Metadata.ThreadingModel.STA)]
class DisplayRequest final
/// [Windows.Foundation.Metadata.ContractVersion(Windows.Foundation.UniversalApiContract, 65536)]
/// [Windows.Foundation.Metadata.MarshalingBehavior(Windows.Foundation.Metadata.MarshalingType.None)]
/// [Windows.Foundation.Metadata.Threading(Windows.Foundation.Metadata.ThreadingModel.STA)]
/// [Windows.Foundation.Metadata.Activatable(65536, "Windows.Foundation.UniversalApiContract")]
class DisplayRequest final
[Windows.Foundation.Metadata.Activatable(65536, typeof(Windows.Foundation.UniversalApiContract))]
[Windows.Foundation.Metadata.ContractVersion(typeof(Windows.Foundation.UniversalApiContract), 65536)]
[Windows.Foundation.Metadata.MarshalingBehavior(Windows.Foundation.Metadata.MarshalingType.None)]
[Windows.Foundation.Metadata.Threading(Windows.Foundation.Metadata.ThreadingModel.STA)]
public sealed class DisplayRequest
[Windows.Foundation.Metadata.ContractVersion(typeof(Windows.Foundation.UniversalApiContract), 65536)]
[Windows.Foundation.Metadata.MarshalingBehavior(Windows.Foundation.Metadata.MarshalingType.None)]
[Windows.Foundation.Metadata.Threading(Windows.Foundation.Metadata.ThreadingModel.STA)]
[Windows.Foundation.Metadata.Activatable(65536, "Windows.Foundation.UniversalApiContract")]
public sealed class DisplayRequest
function DisplayRequest()
Public NotInheritable Class DisplayRequest
繼承
Object Platform::Object IInspectable DisplayRequest
屬性

Windows 需求

裝置系列
Windows 10 (已於 10.0.10240.0 引進)
API contract
Windows.Foundation.UniversalApiContract (已於 v1.0 引進)

範例

下列程式碼 (取自 顯示電源狀態範例 ,) 示範如何啟用、追蹤和釋放顯示要求。

/// <param name="sender"></param> 
/// <param name="e"></param> 
private void Activate_Click(object sender, RoutedEventArgs e)
{
    Error.Text = string.Empty;
    Button b = sender as Button;
    if (b != null)
    {
        try
        {
            if (g_DisplayRequest == null)
            {
                // This call creates an instance of the displayRequest object 
                g_DisplayRequest = new DisplayRequest();
            }
        }
        catch (Exception ex)
        {
            rootPage.NotifyUser("Error Creating Display Request: " + ex.Message, NotifyType.ErrorMessage);
        }

        if (g_DisplayRequest != null)
        {
            try
            {
                // This call activates a display-required request. If successful,  
                // the screen is guaranteed not to turn off automatically due to user inactivity. 
                g_DisplayRequest.RequestActive();
                drCount += 1;
                rootPage.NotifyUser("Display request activated (" + drCount + ")", NotifyType.StatusMessage);
            }
            catch (Exception ex)
            {
                rootPage.NotifyUser("Error: " + ex.Message, NotifyType.ErrorMessage);
            }
        }
    }
}

/// <param name="sender"></param> 
/// <param name="e"></param> 
private void Release_Click(object sender, RoutedEventArgs e)
{
    Error.Text = string.Empty;
    Button b = sender as Button;
    if (b != null)
    {
        if (g_DisplayRequest != null)
        {
            try
            {
                // This call de-activates the display-required request. If successful, the screen 
                // might be turned off automatically due to a user inactivity, depending on the 
                // power policy settings of the system. The requestRelease method throws an exception  
                // if it is called before a successful requestActive call on this object. 
                g_DisplayRequest.RequestRelease();
                drCount -= 1;
                rootPage.NotifyUser("Display request released (" + drCount + ")", NotifyType.StatusMessage);
            }
            catch (Exception ex)
            {
                rootPage.NotifyUser("Error: " + ex.Message, NotifyType.ErrorMessage);
            }
        }
    }
}
''' <param name="sender"></param> 
''' <param name="e"></param> 
Private Sub Activate_Click(sender As Object, e As RoutedEventArgs) 
    ErrorTestBlock.Text = String.Empty 
    Dim b As Button = TryCast(sender, Button) 
    If b IsNot Nothing Then 
        Try 
            If g_DisplayRequest Is Nothing Then 
                ' This call creates an instance of the displayRequest object 
                g_DisplayRequest = New DisplayRequest() 
            End If 
        Catch ex As Exception 
            rootPage.NotifyUser("Error Creating Display Request: " & ex.Message, NotifyType.ErrorMessage) 
        End Try 

        If g_DisplayRequest IsNot Nothing Then 
            Try 
                ' This call activates a display-required request. If successful,  
                ' the screen is guaranteed not to turn off automatically due to user inactivity. 
                g_DisplayRequest.RequestActive() 
                drCount += 1 
                rootPage.NotifyUser("Display request activated (" & drCount & ")", NotifyType.StatusMessage) 
            Catch ex As Exception 
                rootPage.NotifyUser("Error:" & ex.Message, NotifyType.ErrorMessage) 
            End Try 
        End If 
    End If 
End Sub

''' <param name="sender"></param> 
''' <param name="e"></param> 
Private Sub Release_Click(sender As Object, e As RoutedEventArgs) 
    ErrorTestBlock.Text = String.Empty 
    Dim b As Button = TryCast(sender, Button) 
    If b IsNot Nothing Then 
        If g_DisplayRequest IsNot Nothing Then 
            Try 
                ' This call de-activates the display-required request. If successful, the screen 
                ' might be turned off automatically due to a user inactivity, depending on the 
                ' power policy settings of the system. The requestRelease method throws an exception  
                ' if it is called before a successful requestActive call on this object. 
                g_DisplayRequest.RequestRelease() 
                drCount -= 1 
                rootPage.NotifyUser("Display request released (" & drCount & ")", NotifyType.StatusMessage) 
            Catch ex As Exception 
                rootPage.NotifyUser("Error: " & ex.Message, NotifyType.ErrorMessage) 
            End Try 
        End If 
    End If 
End Sub 

備註

為了節省電源並延長電池使用時間,如果系統未偵測到任何使用者活動一段時間,系統就會降低電腦的電源。 視系統電源設定而定,顯示器可能會先呈現暗灰色,可能會顯示幕幕保護裝置,最後可能會關閉顯示器,因為系統進入低電源睡眠狀態。

在沒有使用者輸入的情況下顯示視訊或長時間執行的應用程式,可以藉由呼叫 DisplayRequest.RequestActive來要求顯示器保持開啟狀態。 啟用顯示要求時,裝置的顯示器會在應用程式可見時保持開啟。 當使用者將應用程式移出前景時,系統會停用應用程式的顯示要求,並在應用程式返回前景時重新啟用它們。

顯示要求是累積的 - 每個顯示要求都必須以 個別呼叫 DisplayRequest.RequestRelease來釋放。 當應用程式不再需要顯示時,應用程式應該追蹤作用中的顯示要求數目,並確定所有要求都已發行 (,且每個要求呼叫 DisplayRequest.RequestRelease) 。 如需詳細資訊,請參閱:

使用顯示器要求讓顯示器保持開啟會耗用大量電源。 使用顯示要求時,請使用這些指導方針來獲得最佳應用程式行為。

  • 只有在需要時才使用顯示要求,也就是當預期沒有使用者輸入,但顯示應該保持開啟時。 例如,在全螢幕簡報期間或使用者閱讀電子書時。
  • 不再需要時立即釋放每個顯示要求。

注意

這個類別不是敏捷的,這表示您必須考慮其執行緒模型和封送處理行為。 如需詳細資訊,請參閱執行緒和封送處理 (C++/CX) 在多執行緒環境中使用 Windows 執行階段 物件 (.NET)

Windows Phone 8

只有原生應用程式才支援此 API。

建構函式

DisplayRequest()

建立 DisplayRequest 類別的實例。

方法

RequestActive()

啟動顯示要求。

RequestRelease()

停用顯示要求。

適用於