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我在.Net 4.0 中做了一个屏幕保护程序。它基本上只是移动图像中的位并在计时器上使用 .Invalidate 并覆盖 onPaint 事件来显示它。

到目前为止，它工作得很好——但是——我注意到它有一个问题。

它在暂停超时后停止监视器暂停。自从我安装它以来，我的显示器现在保持 24/7 全天候运行。

问题是，我没有做任何事情来专门停止省电功能 - 我已经确保我的计算机的省电设置已设置（它们是）。所以我选择了另一个屏幕保护程序，以确保设置仍然有效。超时后监视器暂停。

然后我需要做什么才能很好地使用电源管理？我在谷歌上搜索了这个答案，我发现的一切都是如何阻止电源管理，我没有明确阻止它！我只想在适当的时候允许暂停。

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2 回答 2

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您是否会意外捕获WM_SYSCOMMAND的 0xF170 (SC_MONITORPOWER) 子命令？

于 2012-06-06T00:38:29.813 回答
1

我能够让我的程序“玩得很好”。我不知道为什么这有效而原始代码无效，但这不仅有效 - 它实际上使程序更加“节能”友好，因为它通过在屏幕暂停后不进行计算来减少 CPU 周期。简而言之，我预览 WndProc 消息并查找监视器正在暂停消息，一旦收到它，我就会停止重绘，直到它恢复（可以恢复并使屏幕保护程序仍然处于活动状态）。

代码更改：

    // Field Definitions
    /// <summary>
    /// Constants that relate to the WndProc messages we wish to intercept and evaluate.
    /// </summary>
    [System.Diagnostics.CodeAnalysis.SuppressMessage("StyleCop.CSharp.NamingRules", "SA1310:FieldNamesMustNotContainUnderscore", Justification = "Standard practice to use this naming style for Win32 API Constants.")]
    private const int WM_SYSCOMMAND = 0x0112, SC_MONITORPOWER = 0xF170;

    /// <summary>
    /// Gets or sets whether we are suspended. Should coincide with whether the display is turned on or not.
    /// </summary>
    private bool isSuspended = false;


    // New overridden method
    /// <summary>
    /// Intercepts WndProc messages. We are looking for the screen suspend activity. From it, we will return that we are able to suspend and we ourselves will suspend.
    /// </summary>
    /// <param name="m">Message to be checked.</param>
    protected override void WndProc(ref Message m)
    {
        if (m.Msg == WM_SYSCOMMAND)
        {
            // The 0x000F bits are used to indicate the specific state and must be ignored to see if this is a monitor power event.
            if ((m.WParam.ToInt32() & 0xFFF0) == SC_MONITORPOWER)
            {
                switch (m.WParam.ToInt32() & 0x000F)
                {
                    case -1:
                        // Display powering on - resume operation
#if DEBUG
                        System.Diagnostics.Debug.WriteLine("Display powered on.");
#endif
                        this.isSuspended = false;
                        break;
                    case 0:
                    case 1:
                    case 2:
                        // Display being powered off - suspend operation
#if DEBUG
                        System.Diagnostics.Debug.WriteLine("Display suspended");
#endif
                        this.isSuspended = true;
                        break;
                    default:
#if DEBUG
                        System.Diagnostics.Debug.WriteLine(string.Format("Unknown power state: {0}", (m.WParam.ToInt32() & 0x000F).ToString("0")));
#endif
                        // Assuming that unknown values mean to power off. This is a WAG.
                        this.isSuspended = true;
                        break;
                }
            }
        }

        base.WndProc(ref m);
    }


    // Change to my refreshing timer.
    /// <summary>
    /// Called when the refresh timer ticks. This invalidates the form, forcing it to be redrawn, which creates a framerate for us.
    /// </summary>
    /// <param name="sender">Who called this method.</param>
    /// <param name="e">Event Arguments.</param>
    private void RefreshTimer_Tick(object sender, EventArgs e)
    {
        if (this.isSuspended)
        {
            // Program is in suspended mode, so don't do anything this update.
            return;
        }

        // Program is not suspended, so invalidate the client area so it can be painted again.
        this.Invalidate();
    }

进行此更改会在调用挂起时停止所有重绘（并停止 GDI+ 计算），并且在进行此更改后，屏幕保护程序会根据电源管理设置“运行”。

于 2012-06-06T17:21:51.707 回答