UI – Windows Accent Color Theme – C# & WinForm

WinTheme Class

public class WinTheme
{
    //Extern methods
    [DllImport("uxtheme.dll", EntryPoint = "#95")]
    private static extern uint GetImmersiveColorFromColorSetEx(uint dwImmersiveColorSet, uint dwImmersiveColorType,
                                                                bool bIgnoreHighContrast, uint dwHighContrastCacheMode);

    [DllImport("uxtheme.dll", EntryPoint = "#96")]
    private static extern uint GetImmersiveColorTypeFromName(IntPtr pName);

    [DllImport("uxtheme.dll", EntryPoint = "#98")]
    private static extern int GetImmersiveUserColorSetPreference(bool bForceCheckRegistry, bool bSkipCheckOnFail);

    //Public methods
    public static Color GetAccentColor()
    {
        var userColorSet = GetImmersiveUserColorSetPreference(false, false);
        var colorType = GetImmersiveColorTypeFromName(Marshal.StringToHGlobalUni("ImmersiveStartSelectionBackground"));
        var colorSetEx = GetImmersiveColorFromColorSetEx((uint)userColorSet, colorType, false, 0);

        return ConvertDWordColorToRGB(colorSetEx);
    }

    //Private methods
    private static Color ConvertDWordColorToRGB(uint colorSetEx)
    {
        byte redColor = (byte)((0x000000FF & colorSetEx) >> 0);
        byte greenColor = (byte)((0x0000FF00 & colorSetEx) >> 8);
        byte blueColor = (byte)((0x00FF0000 & colorSetEx) >> 16);
        //byte alphaColor = (byte)((0xFF000000 & colorSetEx) >> 24);

        return Color.FromArgb(redColor, greenColor, blueColor);
    }
}

Form Design

Form Code

public partial class Form1 : Form
{
    private UserPreferenceChangedEventHandler UserPreferenceChanged;

    public Form1()
    {
        InitializeComponent();
        LoadTheme();
        UserPreferenceChanged = new UserPreferenceChangedEventHandler(SystemEvents_UserPreferenceChanged);
        SystemEvents.UserPreferenceChanged += UserPreferenceChanged;
        this.Disposed += new EventHandler(Form_Disposed);
    }

    private void LoadTheme()
    {
        var themeColor = WinTheme.GetAccentColor();//Windows Accent Color
        var lightColor = ControlPaint.Light(themeColor);
        var darkColor = ControlPaint.Dark(themeColor);

        panelTitleBar.BackColor = themeColor;
        panelWelcome.BackColor = lightColor;
        panelLine.BackColor = lightColor;
        rjCircularPictureBox1.BorderColor = themeColor;
        rjCircularPictureBox1.BorderColor2 = darkColor;
        labelVersion.ForeColor = lightColor;
        rjButton7.BackColor = darkColor;
        //Buttons
        foreach (Button button in this.Controls.OfType<Button>())
        {
            button.BackColor = themeColor;
        }

        foreach (Button button in this.panelMenu.Controls.OfType<Button>())
        {
            button.FlatAppearance.MouseOverBackColor = themeColor;
            button.FlatAppearance.MouseDownBackColor = lightColor;
        }
    }

    private void SystemEvents_UserPreferenceChanged(object sender, UserPreferenceChangedEventArgs e)
    {
        if (e.Category == UserPreferenceCategory.General || e.Category == UserPreferenceCategory.VisualStyle)
        {
            LoadTheme();
        }
    }

    private void Form_Disposed(object sender, EventArgs e)
    {
        SystemEvents.UserPreferenceChanged -= UserPreferenceChanged;
    }
}

Video Tutorial