richtextbox控件插入链接代码分享

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;
  }
 }
}