Adding designable borders to user controls

using System;
using System.Collections;
using System.ComponentModel;
using System.Drawing;
using System.Data;
using System.Windows.Forms;
using System.Runtime.InteropServices;		// Needed for DLLImport

namespace BorderControls
{
	/// <summary>
	/// Summary description for UserControl1.
	/// </summary>
	public class DesignableControl : System.Windows.Forms.UserControl
	{
		// Set the built-in default border style
		private System.Windows.Forms.BorderStyle borderStyle = BorderStyle.Fixed3D;
		private System.Windows.Forms.Label label;

		/// <summary>
		/// Required designer variable.
		/// </summary>
		private System.ComponentModel.Container components = null;

		public DesignableControl()
		{
			// This call is required by the Windows.Forms Form Designer.
			InitializeComponent();

			// TODO: Add any initialization after the InitComponent call
		}

		/// <summary>
		/// Clean up any resources being used.
		/// </summary>
		protected override void Dispose( bool disposing )
		{
			if( disposing )
			{
				if( components != null )
					components.Dispose();
			}
			base.Dispose( disposing );
		}

		#region Component Designer generated code
		/// <summary>
		/// Required method for Designer support - do not modify 
		/// the contents of this method with the code editor.
		/// </summary>
		private void InitializeComponent()
		{
			this.label = new System.Windows.Forms.Label();
			this.SuspendLayout();
			// 
			// label
			// 
			this.label.Anchor = ((System.Windows.Forms.AnchorStyles)((((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Bottom) 
				| System.Windows.Forms.AnchorStyles.Left) 
				| System.Windows.Forms.AnchorStyles.Right)));
			this.label.Location = new System.Drawing.Point(8, 16);
			this.label.Name = "label";
			this.label.Size = new System.Drawing.Size(72, 23);
			this.label.TabIndex = 0;
			this.label.Text = "Designable";
			this.label.TextAlign = System.Drawing.ContentAlignment.MiddleCenter;
			// 
			// DesignableControl
			// 
			this.Controls.Add(this.label);
			this.Name = "DesignableControl";
			this.Size = new System.Drawing.Size(88, 56);
			this.ResumeLayout(false);

		}
		#endregion


		// These constants were taken from WinUser.h
		private const int WS_BORDER  = 0x00800000;
		private const int WS_EX_CLIENTEDGE = 0x00000200;

		// Convert from the BorderStyle constant types to Style and ExStyle values suitable for Win32
		private void BorderStyleToWindowStyle(ref int style, ref int exStyle)
		{
			style &= ~WS_BORDER;
			exStyle &= ~WS_EX_CLIENTEDGE;

			switch(borderStyle)
			{
				case BorderStyle.Fixed3D:
					exStyle |= WS_EX_CLIENTEDGE;
					break;

				case BorderStyle.FixedSingle:
					style |= WS_BORDER;
					break;

				case BorderStyle.None:
					// No border style values
					break;
			}
		}


		// Provide window style constants to enable control border
		protected override CreateParams CreateParams
		{
			get
			{
				CreateParams p = base.CreateParams;		// Get the default values from the base class
				int style = p.Style;					// Store the Style and ExStyle values
				int exStyle = p.ExStyle;
				BorderStyleToWindowStyle(ref style, ref exStyle);	// Modify the values to match the desired border style
				p.Style = style;
				p.ExStyle = exStyle;					// Store the results
				return p;
			}
		}


		/// <summary>
		/// Gets or sets the border style of the tree view control.
		/// </summary>
		[Category("Appearance")]
		[Description("Border style of the control")]
		[DefaultValue(typeof(System.Windows.Forms.BorderStyle), "Fixed3D")]
		public BorderStyle BorderStyle
		{
			get {return borderStyle;}
			set
			{
				borderStyle = value;

				// Get Styles using Win32 calls
				int style = GetWindowLong(Handle, GWL_STYLE);
				int exStyle = GetWindowLong(Handle, GWL_EXSTYLE);

				// Modify Styles to match the selected border style
				BorderStyleToWindowStyle(ref style, ref exStyle);

				// Set Styles using Win32 calls
				SetWindowLong(Handle, GWL_STYLE, style);
				SetWindowLong(Handle, GWL_EXSTYLE, exStyle);

				// Update window property cache (Tell Win32 that the frame changed)
				SetWindowPos(Handle, IntPtr.Zero, 0, 0, 0, 0,
					SWP_NOACTIVATE | SWP_NOMOVE | SWP_NOSIZE | SWP_NOZORDER |
					SWP_NOOWNERZORDER | SWP_FRAMECHANGED);
			}
		}

		// Constants from WinUser.h
		const int GWL_STYLE = -16;
		const int GWL_EXSTYLE = -20;

		[DllImport("User32", CharSet=CharSet.Auto)]
		private static extern int GetWindowLong(IntPtr hWnd, int Index);

		[DllImport("User32", CharSet=CharSet.Auto)]
		private static extern int SetWindowLong(IntPtr hWnd, int Index, int Value);


		// Constants from WinUser.h
		const uint SWP_NOSIZE   = 0x0001;
		const uint SWP_NOMOVE   = 0x0002;
		const uint SWP_NOZORDER   = 0x0004;
		const uint SWP_NOREDRAW   = 0x0008;
		const uint SWP_NOACTIVATE  = 0x0010;
		const uint SWP_FRAMECHANGED  = 0x0020;
		const uint SWP_SHOWWINDOW  = 0x0040;
		const uint SWP_HIDEWINDOW  = 0x0080;
		const uint SWP_NOCOPYBITS  = 0x0100;
		const uint SWP_NOOWNERZORDER = 0x0200;
		const uint SWP_NOSENDCHANGING = 0x0400;

		[DllImport("User32", ExactSpelling=true)]
		private static extern int SetWindowPos(IntPtr hWnd, IntPtr hWndInsertAfter,
			int x, int y, int cx, int cy, uint uFlags);
	}
}