As of 12-2003, I know of several versions of this control

Riched.dll	236Kb 98	This is identified as a Windows 95 version, but it is not on my Windows 95 system. It is on a Windows 98 system, has the same date, time, and version as one of the Riched32.dll files, but not the same size.
Riched32.dll	174Kb 95 184Kb 98     4Kb XP	This is identified as a Windows 95 version. The Windows XP version is just a wrapper for Riched20.dll.
Riched20.dll	288Kb 95 422Kb 98 417Kb XP	288Kb is version 2; 422Kb and 417Kb are version 3

The built-in help is completely worthless ... except for the sections on how to manipulate selected text.

Scrollbar control is very responsive.

There is no obvious way to disable word wrap!! (give me a break!)
It appears that the RightMargin property controls this. 0 (the default) forces word wrap. Since the value is in twips, use a large value (like 500000) to disable word wrap.
A related example from some c-code supplied with VB

  SendMessage(predoc->hwndRE, EM_SETTARGETDEVICE,
    (WPARAM) predoc->hdcTarget, (LPARAM) xWidth);

Search the help for EM_ (Windows messages) and ES_ (Edit Styles)

' Edit Control Messages - from WIN32API.TXT
Const EM_GETSEL              = &HB0
Const EM_SETSEL              = &HB1  ' Selects all text
Const EM_GETRECT             = &HB2
Const EM_SETRECT             = &HB3
Const EM_SETRECTNP           = &HB4
Const EM_SCROLL              = &HB5  ' Scrolls one page or one line up or down
Const EM_LINESCROLL          = &HB6  ' Goes to end of file only
Const EM_SCROLLCARET         = &HB7  ' Seems ok
Const EM_GETMODIFY           = &HB8
Const EM_SETMODIFY           = &HB9
Const EM_GETLINECOUNT        = &HBA  ' Works
Const EM_LINEINDEX           = &HBB
Const EM_SETHANDLE           = &HBC
Const EM_GETHANDLE           = &HBD  ' Fails - the Borland help explains why
Const EM_GETTHUMB            = &HBE  ' Fails
Const EM_LINELENGTH          = &HC1
Const EM_REPLACESEL          = &HC2
Const EM_GETLINE             = &HC4  ' 
Const EM_LIMITTEXT           = &HC5
Const EM_CANUNDO             = &HC6
Const EM_UNDO                = &HC7
Const EM_FMTLINES            = &HC8
Const EM_LINEFROMCHAR        = &HC9
Const EM_SETTABSTOPS         = &HCB
Const EM_SETPASSWORDCHAR     = &HCC
Const EM_EMPTYUNDOBUFFER     = &HCD
Const EM_GETFIRSTVISIBLELINE = &HCE  ' Works
Const EM_SETREADONLY         = &HCF
Const EM_SETWORDBREAKPROC    = &HD0
Const EM_GETWORDBREAKPROC    = &HD1
Const EM_GETPASSWORDCHAR     = &HD2

EM_GETTHUMB - to retrieve the position of the scroll box (thumb) - Fails
EM_SCROLL - to scroll the text vertically - up or down one page or line
EM_LINESCROLL - to scroll the text vertically or horizontally - Fails

tt = SendMessage(RichTextBox1.hwnd, EM_GETTHUMB, 0, 0)

The EM_SCROLL messages only uses 4 of the 17 ScrollBar constants
(yes, I tried all 8 unique codes).

Const SB_LINEUP   = 0  ' Scrolls  up  one line
Const SB_LINEDOWN = 1  ' Scrolls down one line
Const SB_PAGEUP   = 2  ' Scrolls  up  one page
Const SB_PAGEDOWN = 3  ' Scrolls down one page

procedure TCustomRichEdit.CreateParams(var Params: TCreateParams);
const
  RichEditModuleName = 'RICHED32.DLL';
begin
    FRichEditModule := LoadLibrary(RichEditModuleName);

The LoadLibrary function explains why Depends does NOT list either Riched32.dll or Riched20.dll as one of the required modules.

Notice that this actually selects different controls depending on which operating system is used. Specifically,

• In Windows 98, Riched32.dll and Riched20.dll are separate programs
• In Windows XP, Riched32.dll is just a wrapper for Riched20.dll

  UIRichEdit.SelAttributes.color := clGreen;
  UIRichEdit.WordWrap := false;
  BoldButton.Down := fsBold in RichEdit1.SelAttributes.Style;
    (in is not in the regular help index, search delphi.hlp 
      This example is from the SelAttributes example)
  Memo1.Font.Style := [fsBold]; // Style is a set
                                // The square bracket syntax is not explained
                                //  but it is required for sets

  RichEdit1.Perform(EM_SCROLLCARET, 0, 0); // Directly send a Windows message

   procedure TWinControl.DefaultHandler(var Message);
        Result := CallWindowProc(FDefWndProc, FHandle, Msg, WParam, LParam);

  property WordWrap: Boolean;
  procedure ScrollBy(DeltaX, DeltaY: Integer); // Values are in pixels

   // Set the selection to the beginning of a line
  with RichEdit1 do begin
    SelStart := perform(em_LineIndex, spinedit1.value, 0);

When you copy text to the clipboard, several different formats may be saved.

When you paste from the clipboard, TRichEdit decides which format to use and how to render it.

The default functionality can be observed by simply placing a TRichEdit component on a blank form and running the application.

• Highlight some text on a web page
• Copy it to the clipboard
• Paste it in your TRichEdit component

I have one web page that actually displays html tags (which I use to copy and paste to pages I write using notepad). When these are pasted, the tags are interpreted (kind of defeats the purpose).

The problem is that I just want the clipboard pasted as text with bold, italic and other crap removed. (In this case, I am using TRichEdit as a replacement for TMemo which has a size limitation - ~32K)

While I was not able to find any obvious way to control this (the ability to set a preferred clipboard format would have been nice), I was able to develop a work around. Simply deriving a new component based on TRichEdit does not work because most of the functionality is based on RICHED32.DLL (that is why copy and paste work without adding any additional code.) Instead, I used 2 menu selections and the TEditPaste action to capture the Paste keystrokes and to paste the clipboard data as text.

The following code shows how the TEditPaste action normally works - WM_PASTE instructs the dll to do whatever it wants.

procedure TEditPaste.ExecuteTarget(Target: TObject);
begin
   GetControl(Target).PasteFromClipboard;
end;

procedure TCustomEdit.PasteFromClipboard; 
begin
  SendMessage(Handle, WM_PASTE, 0, 0);
end;

The solution is to

• Create 2 menu items (one for each shortcut key)
• Connect each menu item to the same TEditPaste action
• Set the menu shortcut keys to Ctrl-V and Shift-Ins
• Hide one of the menu items - the shortcut key will still work
• Set the action's OnExecute to the following

procedure TForm1.EditPaste1Execute(Sender: TObject);
begin
  SendMessage(RichEdit1.Handle, EM_PASTESPECIAL, CF_TEXT, 0);
end;

I tried several other approaches, but these did not work. For instance

• I told the form to capture WM_PASTE messages - but the break point was never hit

Notes: When copying from notepad or a TMemo, the clipboard contained 3 formats (1, 16, 7). When pasting these, html code was not interpreted. When copying from Internet Explorer, the clipboard contained 8 formats (51906, 1, 13, 53478, 52434, 51949, 16, 7), 4 of them not defined. When pasting these, html code was interpreted.

****

Use this to search the text

TCustomRichEdit.FindText

From EM_FINDTEXTEX in the Windows SDK help

fuFlags

FT_MATCHCASE
FT_WHOLEWORD

FR_DOWN is new to version 2, It must be added for a version 2 search
        to be the same as a version 1 search

Microsoft SDK

****

How to insert a Smiley image into a TRxRichEdit? shows how to do this with streams and a callback function.

This is unbelievable - I wrote a program using Delphi 5 that used the Microsoft RichEdit control (via TRichEdit).

• It runs perfectly under Windows 98.
• It is completely hosed under Windows XP

If I read an *.rtf file into a TRichEdit, all the rtf codes are automatically removed.

When the PlainText property is true, Windows 98 shows all the text in the file - just like opening the file in notepad. In Windows XP, the rtf codes are removed.

When I try to write an rtf file to disk, all the rtf codes are removed.

When the PlainText property is false, both Windows 98 and Windows XP show the text formatted (colors, fonts, underline, and the like are displayed) - just like opening the file in MS Word. However, when you try to save the file, Windows XP removes the rtf codes and Windows 98 does not.

Copying rtf text from one RichEdit control to another works fine in Windows 98, but causes a resource error in Windows XP. XP RichEdit Design Problem presents a solution using streams.

One of the things that bothers me about this is that I was not able to find any information related to these problems by searching the internet.

This line of code works perfectly in Windows 98, but fails in Windows 2000 (and Windows XP).

  PlainText_UIRichEdit.Text := rtf_string;

  Perform(WM_SETTEXT, 0, Longint(Buffer));
  Perform(CM_TEXTCHANGED, 0, 0);

var
 xx: TStringStream ;
begin
  xx := TStringStream.Create(rtf_string);

  PlainText_UIRichEdit.Lines.LoadFromStream(xx);

  xx.Free;
end;