从C＃WPF更改Windows 8.1桌面的方向

Question

如果我从应用程序中选择Windows 8.1或Windows 7桌面的方向，是否可以通过C＃程序将其从横向更改为纵向？

我知道我们可以从System.Windows.Forms命名空间中的Screen类获取屏幕的宽度和高度信息。

但是，是否可以调用任何API来更改方向。

Answer 1

MSDN中提供了一种解决方案

我为WPF使用了相同的代码。 下面是代码

View.xaml

<Window x:Class="ScreenOrientation.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525">
    <StackPanel Orientation="Horizontal" MaxHeight="55px" VerticalAlignment="Top">
        <Label Content="Change Orientation" Margin="5"></Label>
        <Button Content="Rotate Clock Wise" Margin="5" x:Name="BtnClockwise" Click="BtnClockwise_OnClick"></Button>
        <Button Content="Rotate Anti Clock Wise" Margin="5" x:Name="BtnAntiClock" Click="BtnAntiClock_OnClick"></Button>
    </StackPanel>
</Window>

背后的代码

public partial class MainWindow : Window
{
    private int[] orientationValues = new int[4]{NativeMethods.DMDO_DEFAULT,
                                                    NativeMethods.DMDO_90,
                                                    NativeMethods.DMDO_180,
                                                    NativeMethods.DMDO_270};
    public MainWindow()
    {
        InitializeComponent();
    }

    private void BtnClockwise_OnClick(object sender, RoutedEventArgs e)
    {
        // obtain current settings
        DEVMODE dm = NativeMethods.CreateDevmode();
        GetSettings(ref dm);

        // swap height and width
        int temp = dm.dmPelsHeight;
        dm.dmPelsHeight = dm.dmPelsWidth;
        dm.dmPelsWidth = temp;

        // set the orientation value to what's next anti-clockwise
        int index = Array.IndexOf(orientationValues, (object)dm.dmDisplayOrientation);
        int newIndex = (index == 3) ? 0 : index + 1;
        dm.dmDisplayOrientation = orientationValues[newIndex];

        // switch to new settings
        ChangeSettings(dm);
    }

    private void BtnAntiClock_OnClick(object sender, RoutedEventArgs e)
    {
        // obtain current settings
        DEVMODE dm = NativeMethods.CreateDevmode();
        GetSettings(ref dm);

        // swap height and width
        int temp = dm.dmPelsHeight;
        dm.dmPelsHeight = dm.dmPelsWidth;
        dm.dmPelsWidth = temp;

        // set the orientation value to what's next anti-clockwise
        int index = Array.IndexOf(orientationValues, (object)dm.dmDisplayOrientation);
        int newIndex = (index == 3) ? 0 : index + 1;
        dm.dmDisplayOrientation = orientationValues[newIndex];

        // switch to new settings
        ChangeSettings(dm);
    }


    private int GetSettings(ref DEVMODE dm)
    {
        // helper to obtain current settings
        return GetSettings(ref dm, NativeMethods.ENUM_CURRENT_SETTINGS);
    }

    private int GetSettings(ref DEVMODE dm, int iModeNum)
    {
        // helper to wrap EnumDisplaySettings Win32 API
        return NativeMethods.EnumDisplaySettings(null, iModeNum, ref dm);
    }

    private void ChangeSettings(DEVMODE dm)
    {
        // helper to wrap ChangeDisplaySettings Win32 API
        int iRet = NativeMethods.ChangeDisplaySettings(ref dm, 0);
        switch (iRet)
        {
            case NativeMethods.DISP_CHANGE_SUCCESSFUL:
                break;
            case NativeMethods.DISP_CHANGE_RESTART:
                MessageBox.Show("Please restart your system");
                break;
            case NativeMethods.DISP_CHANGE_FAILED:
                MessageBox.Show("ChangeDisplaySettigns API failed");
                break;
            case NativeMethods.DISP_CHANGE_BADDUALVIEW:
                MessageBox.Show("The settings change was unsuccessful because system is DualView capable.");
                break;
            case NativeMethods.DISP_CHANGE_BADFLAGS:
                MessageBox.Show("An invalid set of flags was passed in.");
                break;
            case NativeMethods.DISP_CHANGE_BADPARAM:
                MessageBox.Show("An invalid parameter was passed in. This can include an invalid flag or combination of flags.");
                break;
            case NativeMethods.DISP_CHANGE_NOTUPDATED:
                MessageBox.Show("Unable to write settings to the registry.");
                break;
            default:
                MessageBox.Show("Unknown return value from ChangeDisplaySettings API");
                break;
        }
    }
}

DEVMOD结构

[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi)]
public struct DEVMODE
{
    [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 32)]
    public string dmDeviceName;

    public short dmSpecVersion;
    public short dmDriverVersion;
    public short dmSize;
    public short dmDriverExtra;
    public int dmFields;
    public int dmPositionX;
    public int dmPositionY;
    public int dmDisplayOrientation;
    public int dmDisplayFixedOutput;
    public short dmColor;
    public short dmDuplex;
    public short dmYResolution;
    public short dmTTOption;
    public short dmCollate;

    [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 32)]
    public string dmFormName;

    public short dmLogPixels;
    public short dmBitsPerPel;
    public int dmPelsWidth;
    public int dmPelsHeight;
    public int dmDisplayFlags;
    public int dmDisplayFrequency;
    public int dmICMMethod;
    public int dmICMIntent;
    public int dmMediaType;
    public int dmDitherType;
    public int dmReserved1;
    public int dmReserved2;
    public int dmPanningWidth;
    public int dmPanningHeight;
};

public class NativeMethods
{
    // PInvoke declaration for EnumDisplaySettings Win32 API
    [DllImport("user32.dll", CharSet = CharSet.Ansi)]
    public static extern int EnumDisplaySettings(string lpszDeviceName, int iModeNum, ref DEVMODE lpDevMode);

    // PInvoke declaration for ChangeDisplaySettings Win32 API
    [DllImport("user32.dll", CharSet = CharSet.Ansi)]
    public static extern int ChangeDisplaySettings(ref DEVMODE lpDevMode, int dwFlags);

    // helper for creating an initialized DEVMODE structure
    public static DEVMODE CreateDevmode()
    {
        DEVMODE dm = new DEVMODE();
        dm.dmDeviceName = new String(new char[32]);
        dm.dmFormName = new String(new char[32]);
        dm.dmSize = (short)Marshal.SizeOf(dm);
        return dm;
    }

    // constants
    public const int ENUM_CURRENT_SETTINGS = -1;
    public const int DISP_CHANGE_SUCCESSFUL = 0;
    public const int DISP_CHANGE_BADDUALVIEW = -6;
    public const int DISP_CHANGE_BADFLAGS = -4;
    public const int DISP_CHANGE_BADMODE = -2;
    public const int DISP_CHANGE_BADPARAM = -5;
    public const int DISP_CHANGE_FAILED = -1;
    public const int DISP_CHANGE_NOTUPDATED = -3;
    public const int DISP_CHANGE_RESTART = 1;
    public const int DMDO_DEFAULT = 0;
    public const int DMDO_90 = 1;
    public const int DMDO_180 = 2;
    public const int DMDO_270 = 3;
}