Source code for htmlentities.cs

using System;

using System.Text.RegularExpressions;

using System.Web;

using System.Windows.Forms;

namespace RobvanderWoude

{

	static class HTMLEntities

	{

		/// <summary>

		///  The main entry point for the application.

		/// </summary>

		[STAThread]

		static void Main()

		{

			Application.SetHighDpiMode( HighDpiMode.SystemAware );

			Application.EnableVisualStyles( );

			Application.SetCompatibleTextRenderingDefault( false );

			Application.Run( new FormHTMLEntities( ) );

		}

	}

	public partial class FormHTMLEntities : Form

	{

		private void ConvertUnicode()

		{

			if ( !string.IsNullOrWhiteSpace( this.textBoxUnicode.Text ) )

			{

				int entity = Convert.ToInt32( (char)this.textBoxUnicode.Text[0] );

				this.textBoxHTMLEntity.Text = entity.ToString( );

				this.textBoxURLEncoded.Text = HttpUtility.UrlEncode( this.textBoxUnicode.Text );

				MoveCursorToEnd( );

			}

		}

		private void MoveCursorToEnd()

		{

			this.textBoxHTMLEntity.SelectionStart = this.textBoxHTMLEntity.Text.Length;

			this.textBoxHTMLEntity.SelectionLength = 0;

			this.textBoxUnicode.SelectionStart = this.textBoxUnicode.Text.Length;

			this.textBoxUnicode.SelectionLength = 0;

			this.textBoxURLEncoded.SelectionStart = this.textBoxURLEncoded.Text.Length;

			this.textBoxURLEncoded.SelectionLength = 0;

		}

		private void ValidateHTMLEntity()

		{

			string text = this.textBoxHTMLEntity.Text;

			Regex regex = new Regex( "[^\\d]" );

			if ( regex.IsMatch( text ) )

			{

				int cursorpos = this.textBoxHTMLEntity.SelectionStart + this.textBoxHTMLEntity.SelectionLength;

				text = regex.Replace( text, "" );

				this.textBoxHTMLEntity.SelectionStart = Math.Min( cursorpos, text.Length );

				this.textBoxHTMLEntity.SelectionLength = 0;

			}

			else if ( text.Length > 1 )

			{

				int entity = Convert.ToInt32( text );

				this.textBoxUnicode.Text = System.Net.WebUtility.HtmlDecode( string.Format( "&#{0};", text ) );

				this.textBoxURLEncoded.Text = HttpUtility.UrlEncode( this.textBoxUnicode.Text );

			}

		}

		private void ValidatURLEncoded()

		{

			string text = this.textBoxURLEncoded.Text;

			Regex regex = new Regex( "[^%\\dA-Fa-f]" );

			if ( regex.IsMatch( text ) )

			{

				int cursorpos = this.textBoxURLEncoded.SelectionStart + this.textBoxURLEncoded.SelectionLength;

				text = regex.Replace( text, "" );

				this.textBoxURLEncoded.SelectionStart = Math.Min( cursorpos, text.Length );

				this.textBoxURLEncoded.SelectionLength = 0;

			}

			else if ( text.Length > 2 )

			{

				regex = new Regex( "^(%[\\dA-Fa-f]{2}){1,2}$" );

				if ( regex.IsMatch( text ) )

				{

					char newchar = HttpUtility.UrlDecode( text )[0];

					this.textBoxUnicode.Text = newchar.ToString( );

					int entity = Convert.ToInt32( newchar );

					this.textBoxHTMLEntity.Text = entity.ToString( );

				}

				else

				{

					this.textBoxUnicode.Text = string.Empty;

					this.textBoxHTMLEntity.Text = string.Empty;

				}

			}

		}

	}

}