using System; using System.ComponentModel; using System.Drawing; using System.Windows.Forms; using System.Runtime.InteropServices; namespace RichTextBoxLinks {  public class RichTextBoxEx : RichTextBox  {   #region Interop-Defines   [ StructLayout( LayoutKind.Sequential )]   private struct CHARFORMAT2_STRUCT   {    public UInt32 cbSize;    public UInt32   dwMask;    public UInt32   dwEffects;    public Int32    yHeight;    public Int32    yOffset;    public Int32 crTextColor;    public byte     bCharSet;    public byte     bPitchAndFamily;    [MarshalAs(UnmanagedType.ByValArray, SizeConst=32)]    public char[]   szFaceName;    public UInt16 wWeight;    public UInt16 sSpacing;    public int  crBackColor; // Color.ToArgb() -> int    public int  lcid;    public int  dwReserved;    public Int16 sStyle;    public Int16 wKerning;    public byte  bUnderlineType;    public byte  bAnimation;    public byte  bRevAuthor;    public byte  bReserved1;   }   [DllImport("user32.dll", CharSet=CharSet.Auto)]   private static extern IntPtr SendMessage(IntPtr hWnd, int msg, IntPtr wParam, IntPtr lParam);   private const int WM_USER    = 0x0400;   private const int EM_GETCHARFORMAT  = WM_USER+58;   private const int EM_SETCHARFORMAT  = WM_USER+68;   private const int SCF_SELECTION = 0x0001;   private const int SCF_WORD  = 0x0002;   private const int SCF_ALL  = 0x0004;   #region CHARFORMAT2 Flags   private const UInt32 CFE_BOLD  = 0x0001;   private const UInt32 CFE_ITALIC  = 0x0002;   private const UInt32 CFE_UNDERLINE = 0x0004;   private const UInt32 CFE_STRIKEOUT = 0x0008;   private const UInt32 CFE_PROTECTED = 0x0010;   private const UInt32 CFE_LINK  = 0x0020;   private const UInt32 CFE_AUTOCOLOR = 0x40000000;   private const UInt32 CFE_SUBSCRIPT = 0x00010000;  /* Superscript and subscript are */   private const UInt32 CFE_SUPERSCRIPT= 0x00020000;  /*  mutually exclusive    */   private const int CFM_SMALLCAPS  = 0x0040;   /* (*) */   private const int CFM_ALLCAPS  = 0x0080;   /* Displayed by 3.0 */   private const int CFM_HIDDEN  = 0x0100;   /* Hidden by 3.0 */   private const int CFM_OUTLINE  = 0x0200;   /* (*) */   private const int CFM_SHADOW  = 0x0400;   /* (*) */   private const int CFM_EMBOSS  = 0x0800;   /* (*) */   private const int CFM_IMPRINT  = 0x1000;   /* (*) */   private const int CFM_DISABLED  = 0x2000;   private const int CFM_REVISED  = 0x4000;   private const int CFM_BACKCOLOR  = 0x04000000;   private const int CFM_LCID   = 0x02000000;   private const int CFM_UNDERLINETYPE = 0x00800000;  /* Many displayed by 3.0 */   private const int CFM_WEIGHT  = 0x00400000;   private const int CFM_SPACING  = 0x00200000;  /* Displayed by 3.0 */   private const int CFM_KERNING  = 0x00100000;  /* (*) */   private const int CFM_STYLE   = 0x00080000;  /* (*) */   private const int CFM_ANIMATION  = 0x00040000;  /* (*) */   private const int CFM_REVAUTHOR  = 0x00008000;   private const UInt32 CFM_BOLD  = 0x00000001;   private const UInt32 CFM_ITALIC  = 0x00000002;   private const UInt32 CFM_UNDERLINE = 0x00000004;   private const UInt32 CFM_STRIKEOUT = 0x00000008;   private const UInt32 CFM_PROTECTED = 0x00000010;   private const UInt32 CFM_LINK  = 0x00000020;   private const UInt32 CFM_SIZE  = 0x80000000;   private const UInt32 CFM_COLOR  = 0x40000000;   private const UInt32 CFM_FACE  = 0x20000000;   private const UInt32 CFM_OFFSET  = 0x10000000;   private const UInt32 CFM_CHARSET = 0x08000000;   private const UInt32 CFM_SUBSCRIPT = CFE_SUBSCRIPT | CFE_SUPERSCRIPT;   private const UInt32 CFM_SUPERSCRIPT= CFM_SUBSCRIPT;   private const byte CFU_UNDERLINENONE  = 0x00000000;   private const byte CFU_UNDERLINE   = 0x00000001;   private const byte CFU_UNDERLINEWORD  = 0x00000002; /* (*) displayed as ordinary underline */   private const byte CFU_UNDERLINEDOUBLE  = 0x00000003; /* (*) displayed as ordinary underline */   private const byte CFU_UNDERLINEDOTTED  = 0x00000004;   private const byte CFU_UNDERLINEDASH  = 0x00000005;   private const byte CFU_UNDERLINEDASHDOT  = 0x00000006;   private const byte CFU_UNDERLINEDASHDOTDOT = 0x00000007;   private const byte CFU_UNDERLINEWAVE  = 0x00000008;   private const byte CFU_UNDERLINETHICK  = 0x00000009;   private const byte CFU_UNDERLINEHAIRLINE = 0x0000000A; /* (*) displayed as ordinary underline */   #endregion   #endregion   public RichTextBoxEx()   {    // Otherwise, non-standard links get lost when user starts typing    // next to a non-standard link    this.DetectUrls = false;   }   [DefaultValue(false)]   public new bool DetectUrls   {    get { return base.DetectUrls; }    set { base.DetectUrls = value; }   }   /// <summary>   /// Insert a given text as a link into the RichTextBox at the current insert position.   /// </summary>   /// <param name="text">Text to be inserted</param>   public void InsertLink(string text)   {    InsertLink(text, this.SelectionStart);   }   /// <summary>   /// Insert a given text at a given position as a link.   /// </summary>   /// <param name="text">Text to be inserted</param>   /// <param name="position">Insert position</param>   public void InsertLink(string text, int position)   {    if (position < 0 || position > this.Text.Length)     throw new ArgumentOutOfRangeException("position");    this.SelectionStart = position;    this.SelectedText = text;    this.Select(position, text.Length);    this.SetSelectionLink(true);    this.Select(position + text.Length, 0);   }   /// <summary>   /// Insert a given text at at the current input position as a link.   /// The link text is followed by a hash (#) and the given hyperlink text, both of   /// them invisible.   /// When clicked on, the whole link text and hyperlink string are given in the   /// LinkClickedEventArgs.   /// </summary>   /// <param name="text">Text to be inserted</param>   /// <param name="hyperlink">Invisible hyperlink string to be inserted</param>   public void InsertLink(string text, string hyperlink)   {    InsertLink(text, hyperlink, this.SelectionStart);   }   /// <summary>   /// Insert a given text at a given position as a link. The link text is followed by   /// a hash (#) and the given hyperlink text, both of them invisible.   /// When clicked on, the whole link text and hyperlink string are given in the   /// LinkClickedEventArgs.   /// </summary>   /// <param name="text">Text to be inserted</param>   /// <param name="hyperlink">Invisible hyperlink string to be inserted</param>   /// <param name="position">Insert position</param>   public void InsertLink(string text, string hyperlink, int position)   {    if (position < 0 || position > this.Text.Length)     throw new ArgumentOutOfRangeException("position");    this.SelectionStart = position;    this.SelectedRtf = @"{\rtf1\ansi "+text+@"\v #"+hyperlink+@"\v0}";    this.Select(position, text.Length + hyperlink.Length + 1);    this.SetSelectionLink(true);    this.Select(position + text.Length + hyperlink.Length + 1, 0);   }   /// <summary>   /// Set the current selection's link style   /// </summary>   /// <param name="link">true: set link style, false: clear link style</param>   public void SetSelectionLink(bool link)   {    SetSelectionStyle(CFM_LINK, link ? CFE_LINK : 0);   }   /// <summary>   /// Get the link style for the current selection   /// </summary>   /// <returns>0: link style not set, 1: link style set, -1: mixed</returns>   public int GetSelectionLink()   {    return GetSelectionStyle(CFM_LINK, CFE_LINK);   }   private void SetSelectionStyle(UInt32 mask, UInt32 effect)   {    CHARFORMAT2_STRUCT cf = new CHARFORMAT2_STRUCT();    cf.cbSize = (UInt32)Marshal.SizeOf(cf);    cf.dwMask = mask;    cf.dwEffects = effect;    IntPtr wpar = new IntPtr(SCF_SELECTION);    IntPtr lpar = Marshal.AllocCoTaskMem( Marshal.SizeOf( cf ) );    Marshal.StructureToPtr(cf, lpar, false);    IntPtr res = SendMessage(Handle, EM_SETCHARFORMAT, wpar, lpar);    Marshal.FreeCoTaskMem(lpar);   }   private int GetSelectionStyle(UInt32 mask, UInt32 effect)   {    CHARFORMAT2_STRUCT cf = new CHARFORMAT2_STRUCT();    cf.cbSize = (UInt32)Marshal.SizeOf(cf);    cf.szFaceName = new char[32];    IntPtr wpar = new IntPtr(SCF_SELECTION);    IntPtr lpar =  Marshal.AllocCoTaskMem( Marshal.SizeOf( cf ) );    Marshal.StructureToPtr(cf, lpar, false);    IntPtr res = SendMessage(Handle, EM_GETCHARFORMAT, wpar, lpar);    cf = (CHARFORMAT2_STRUCT)Marshal.PtrToStructure(lpar, typeof(CHARFORMAT2_STRUCT));    int state;    // dwMask holds the information which properties are consistent throughout the selection:    if ((cf.dwMask & mask) == mask)    {     if ((cf.dwEffects & effect) == effect)      state = 1;     else      state = 0;    }    else    {     state = -1;    }    Marshal.FreeCoTaskMem(lpar);    return state;   }  } }