using Syncfusion.Windows.Forms;

namespace MyWinFormsApp
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            
            // Create SkinManager instance
            SkinManager skinManager1 = new SkinManager(this.components);
            
            // Apply theme to entire form (all Syncfusion controls)
            skinManager1.Controls = this;
            skinManager1.VisualTheme = VisualTheme.Office2016Black;
        }
    }
}

using Syncfusion.Windows.Forms;
using Syncfusion.WinForms.Themes;

static class Program
{
    [STAThread]
    static void Main()
    {
        // Load theme assembly (for Office2019, Office2016, HighContrast)
        SkinManager.LoadAssembly(typeof(Office2019Theme).Assembly);
        
        // Set application-wide theme
        SkinManager.ApplicationVisualTheme = "Office2019Colorful";
        
        Application.EnableVisualStyles();
        Application.SetCompatibleTextRenderingDefault(false);
        Application.Run(new Form1());
    }
}

// Apply theme to all Syncfusion controls in a form
SkinManager skinManager1 = new SkinManager(this.components);
skinManager1.Controls = this; // 'this' refers to the form
skinManager1.VisualTheme = VisualTheme.Office2016White;

// Option 1: Using SkinManager
skinManager1.Controls = treeViewAdv1;
skinManager1.VisualTheme = VisualTheme.Office2016Colorful;

// Option 2: Using ThemeName property
this.treeViewAdv1.ThemeName = "Office2019Colorful";

// Office2019 themes
SkinManager.LoadAssembly(typeof(Office2019Theme).Assembly);

// Office2016 themes (for SfDataGrid, SfButton, etc.)
SkinManager.LoadAssembly(typeof(Syncfusion.WinForms.Themes.Office2016Theme).Assembly);

// HighContrast themes
SkinManager.LoadAssembly(typeof(HighContrastTheme).Assembly);

// For Theme Studio themes, customize using ThemeStyle
this.treeViewAdv1.ThemeName = "Office2019Colorful";
this.treeViewAdv1.ThemeStyle.BackColor = System.Drawing.Color.White;
this.treeViewAdv1.ThemeStyle.BorderColor = System.Drawing.Color.SteelBlue;
this.treeViewAdv1.ThemeStyle.TreeNodeAdvStyle.TextColor = System.Drawing.Color.Red;