c# 调整屏幕亮度 SetMonitorBrightness dxva2.dll

1、先注册函数

#region 屏幕亮度
[DllImport("dxva2.dll")]
public static extern bool SetMonitorBrightness(IntPtr hMonitor, short brightness);

[DllImport("dxva2.dll")]
public static extern bool GetMonitorBrightness(IntPtr hMonitor, ref short pdwMinimumBrightness,
    ref short pdwCurrentBrightness, ref short pdwMaximumBrightness);

[DllImport("dxva2.dll")]
public static extern bool GetNumberOfPhysicalMonitorsFromHMONITOR(IntPtr hMonitor,
    ref uint pdwNumberOfPhysicalMonitors);

[DllImport("dxva2.dll")]
public static extern bool GetPhysicalMonitorsFromHMONITOR(IntPtr hMonitor,
    uint dwPhysicalMonitorArraySize, [Out] PhysicalMonitor[] pPhysicalMonitorArray);

[DllImport("user32.dll")]
public static extern IntPtr MonitorFromWindow([In] IntPtr hwnd, uint dwFlags);
#endregion

2、方法

/// <summary>
/// 物理常量
/// </summary>
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
public struct PhysicalMonitor
{
    public IntPtr hPhysicalMonitor;

    [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 128)]
    public string szPhysicalMonitorDescription;
}

/// <summary>
/// 设置屏幕亮度
/// </summary>
/// <param name="handle">所在屏幕窗口的句柄</param>
/// <param name="brightness">亮度</param>
/// <returns></returns>
public static bool SetBrightness(IntPtr handle, short brightness)
{
    if (handle == IntPtr.Zero)
    {
        return false;
    }

    uint pdwNumberOfPhysicalMonitors = uint.MinValue;
    //获取屏幕所在的屏幕设备
    var hMonitor = MonitorFromWindow(handle, 1);
    GetNumberOfPhysicalMonitorsFromHMONITOR(hMonitor, ref pdwNumberOfPhysicalMonitors);
    var screen = new PhysicalMonitor[pdwNumberOfPhysicalMonitors];
    GetPhysicalMonitorsFromHMONITOR(hMonitor, pdwNumberOfPhysicalMonitors, screen);

    return screen.Length <= 0 ? false : SetMonitorBrightness(screen[0].hPhysicalMonitor, brightness);
}

/// <summary>
/// 得到屏幕亮度参数
/// </summary>
/// <param name="handle">所在屏幕窗口的句柄</param>
/// <param name="minBrightness">最小亮度</param>
/// <param name="currentBrightness">当前亮度</param>
/// <param name="maxBrightness">最大亮度</param>
/// <returns></returns>
public static bool GetBrightness(IntPtr handle, ref short minBrightness,
    ref short currentBrightness,
    ref short maxBrightness)
{
    if (handle == IntPtr.Zero)
    {
        return false;
    }

    uint pdwNumberOfPhysicalMonitors = uint.MinValue;
    //获取屏幕所在的屏幕设备
    var hMonitor = MonitorFromWindow(handle, 1);
    GetNumberOfPhysicalMonitorsFromHMONITOR(hMonitor, ref pdwNumberOfPhysicalMonitors);
    var screen = new PhysicalMonitor[pdwNumberOfPhysicalMonitors];
    GetPhysicalMonitorsFromHMONITOR(hMonitor, pdwNumberOfPhysicalMonitors, screen);

    return screen.Length <= 0 ? false : GetMonitorBrightness(screen[0].hPhysicalMonitor, ref minBrightness,
        ref currentBrightness,
        ref maxBrightness);
}

3、用法

DialogTool.SetBrightness(this.Handle, 45);

short minBrightness = 0;
short currentBrightness = 0;
short maxBrightness = 0;

DialogTool.GetBrightness(this.Handle,
    ref minBrightness,
    ref currentBrightness,
    ref maxBrightness);

Trace.WriteLine($"最小：{minBrightness},当前亮度:{currentBrightness},最大亮度:{maxBrightness}");