Library tutorials & articles
RichTextBox Control
Multiple undo/redo
The RichTextBox actually supports multiple undo and redo. However, this functionality is hidden from VB programmers. In order to be able to use the undo and redo facilities, you need to add the following code.
Add this code to the Form_Load() event of the form that contains the RichTextBox control. We are calling the RichTextBox rtfText
Dim lStyle As Long
'// required to 'reveal' multiple undo
'// set rich text box style
lStyle = TM_RICHTEXT Or TM_MULTILEVELUNDO Or TM_MULTICODEPAGE
SendMessageLong rtfText.hwnd, EM_SETTEXTMODE, lStyle, 0
Then, add the code below. This code also adds cut/copy/paste/clear functionality, and expects the following menu items:
| Menu Name | Caption |
| mnuEdit | &Edit |
| mnuEditUndo | &Undo |
| mnuEditRedo | &Redo |
| mnuEditCut | Cu&t |
| mnuEditCopy | &Copy |
| mnuEditPaste | &Paste |
| mnuEditClear | C&lear |
Call the UpdateItems procedure in the mnuEdit_Click() event. This procedure updates the menu items.
Public Property Get UndoType() As ERECUndoTypeConstants
UndoType = SendMessageLong(rtfText.hWnd, EM_GETUNDONAME,
0, 0)
End Property
Public Property Get RedoType() As ERECUndoTypeConstants
RedoType = SendMessageLong(rtfText.hWnd, EM_GETREDONAME,
0, 0)
End Property
Public Property Get CanPaste() As Boolean
CanPaste = SendMessageLong(rtfText.hWnd, EM_CANPASTE, 0, 0)
End Property
Public Property Get CanCopy() As Boolean
If rtfText.SelLength > 0 Then
CanCopy = True
End If
End Property
Public Property Get CanUndo() As Boolean
CanUndo = SendMessageLong(rtfText.hWnd, EM_CANUNDO, 0, 0)
End Property
Public Property Get CanRedo() As Boolean
CanRedo = SendMessageLong(rtfText.hWnd, EM_CANREDO, 0, 0)
End Property
'///////////////////////////////////////////////////////
'// Methods
Public Sub Undo()
SendMessageLong rtfText.hWnd, EM_UNDO, 0, 0
End Sub
Public Sub Redo()
SendMessageLong rtfText.hWnd, EM_REDO, 0, 0
End Sub
Public Sub Cut()
SendMessageLong rtfText.hWnd, WM_CUT, 0, 0
End Sub
Public Sub Copy()
SendMessageLong rtfText.hWnd, WM_COPY, 0, 0
End Sub
Public Sub Paste()
SendMessageLong rtfText.hWnd, WM_PASTE, 0, 0
End Sub
Public Sub Clear()
rtfText.SelText = Empty
End Sub
Public Sub UpdateItems()
Dim bCanUndo As Boolean
'// Undo/Redo options:
bCanUndo = CanUndo
mnuEditUndo.Enabled = bCanUndo
'// Set Undo Text
If (bCanUndo) Then
mnuEditUndo.Caption = "&Undo
" & TranslateUndoType(UndoType)
Else
mnuEditUndo.Caption = "&Undo"
End If
'// Set Redo Text
bCanUndo = CanRedo
If (bCanUndo) Then
mnuEditRedo.Caption = "&Redo
" & TranslateUndoType(RedoType)
Else
mnuEditRedo.Caption = "&Redo"
End If
mnuEditRedo.Enabled = bCanUndo
tbToolBar.Buttons("Redo").Enabled = bCanUndo
'// Cut/Copy/Paste/Clear options
mnuEditCut.Enabled = CanCopy
mnuEditCopy.Enabled = CanCopy
mnuEditPaste.Enabled = CanPaste
mnuEditClear.Enabled = CanCopy
End Sub
'// Returns the undo/redo type
Private Function TranslateUndoType(ByVal eType As ERECUndoTypeConstants) As
String
Select Case eType
Case ercUID_UNKNOWN
TranslateUndoType = "Last Action"
Case ercUID_TYPING
TranslateUndoType = "Typing"
Case ercUID_PASTE
TranslateUndoType = "Paste"
Case ercUID_DRAGDROP
TranslateUndoType = "Drag Drop"
Case ercUID_DELETE
TranslateUndoType = "Delete"
Case ercUID_CUT
TranslateUndoType = "Cut"
End Select
End Function
Then, add this code to a module
'// View Types
Public Enum ERECViewModes
ercDefault = 0
ercWordWrap = 1
ercWYSIWYG = 2
End Enum
'// Undo Types
Public Enum ERECUndoTypeConstants
ercUID_UNKNOWN = 0
ercUID_TYPING = 1
ercUID_DELETE = 2
ercUID_DRAGDROP = 3
ercUID_CUT = 4
ercUID_PASTE = 5
End Enum
'// Text Modes
Public Enum TextMode
TM_PLAINTEXT = 1
TM_RICHTEXT = 2 ' /* default behavior */
TM_SINGLELEVELUNDO = 4
TM_MULTILEVELUNDO = 8 ' /* default behavior */
TM_SINGLECODEPAGE = 16
TM_MULTICODEPAGE = 32 ' /* default behavior */
End Enum
Public Const WM_COPY = &H301
Public Const WM_CUT = &H300
Public Const WM_PASTE = &H302
Public Const WM_USER = &H400
Public Const EM_SETTEXTMODE = (WM_USER + 89)
Public Const EM_UNDO = &HC7
Public Const EM_REDO = (WM_USER + 84)
Public Const EM_CANPASTE = (WM_USER + 50)
Public Const EM_CANUNDO = &HC6&
Public Const EM_CANREDO = (WM_USER + 85)
Public Const EM_GETUNDONAME = (WM_USER + 86)
Public Const EM_GETREDONAME = (WM_USER + 87)
Public Declare Function SendMessageLong Lib "user32" Alias "SendMessageA" (ByVal
hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, ByVal lParam As Long)
As Long
Public Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal
hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, ByVal lParam As Any)
As Long
And that's it! What you thought is impossible, is actually possible in a few lines of code. Of course, it would have been much easier if Microsoft had provided these functions for VB programmers anyway. This code has been adapted from VB Accelerator's RichEdit control.
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This is long past the topic post date but...
I used the selection method (where you select text and then update it), for formatting the output of an application's process in a RTF. This worked great until I needed to buffer the contents of the RTF. Once I started removing content from the RTF, the formatting I had applied through the selection method caused other text to be come improperly formatted.
I am now proceeding with the inserting text as RTF method.
I am had the same proplems;
RichTextBox1.SelectionFont.Bold
RichTextBox1.SelectionFont.Underline etc are readonly
Solved them the following way
Me.RichTextBox1.SelectionColor = Color.Blue Me.RichTextBox1.SelectionFont = New System.Drawing.Font("Tahoma", 8.25!, System.Drawing.FontStyle.Bold) Me.RichTextBox1.SelectedText = BlueBoldTextMe.RichTextBox1.SelectionColor = Color.Black
Me.RichTextBox1.SelectionFont = New System.Drawing.Font("Tahoma", 8.25!, System.Drawing.FontStyle.Regular)
Me.RichTextBox1.SelectedText = BlackRegularText
Kylua, your efforts were not wasted...
You have probably saved me a week's worth of head-pounding. Why it is so difficult to programmatically modify RTF using this control is beyond me. All of the examples I have seen rely on the .Find method to select the text you want to modify.
I am still going to learn the intricacies of RTF and what the difference is between a replace and simply assigning a string. Maybe there's some hidden header we can't see in the RTF property that an assignment overwrites but a replace does not.
Anyway, thanks for sharing this!![Big Smile [:D]](/emoticons/emotion-2a.gif)
I spent AGES working thru this one and couldn't find it anywhere!
The basic problem is that you have to update the richtextbox.rtf, not .text.
And it is very fussy about goes in there!!
A quick and dirty method is to set the richtextbox.text to a value such as "WHATEVER" and then replace that in the richtextbox.rtf with your rtf enabled code. As for what .rtf recognises in formatting, I resorted to copying and pasting rtf into the richtextbox and then looking at the .rtf value.
I only wanted a bit of bold!! By the time I had sorted it out I had decided on a different display method anyway so I hope someone uses this so I haven't wasted my time!!
The working code from my project, before I dump it:
richtextbox.Text =
"REPLACETHIS"Do While Not EOF(1)
Input(1, aLine)
info = Split(Replace(aLine, "\", "\\"), ",")
TempInfo = TempInfo & "\b Result Displayed: \b0" & info(1) & " \par " & "\b URL: \b0 " & info(0) & " \par " & "\b Interval: \b0 " & info(2) & " \par " & "\b Log Path: \b0 " & info(3) & " \par " & " \par "
Loop
richtextbox.Rtf = Replace(richtextbox.Rtf, "REPLACETHIS", TempInfo)
I've just done bolds and replaced the slashes as I was showing URLs and file paths.
James Crowley:
I am using vb6sp6(EMSETTEXTMODE didn't work with vb6sp4 either) RTB control, I have already implemented URL detection similar to yours. However now i am trying to get MULTI-LEVEL UNDO to work, which you stated can be revealed with EMSETTEXTMODE. My attempts at setting a value(42 or any value for that matter) using EMSETTEXTMODE(WMUSER+89) have been unsuccessful, by using EMGETTEXTMODE(WMUSER+90) to read the value(EMGETTEXTMODE always returns a 38). I have previously cleared the RTB with WMSETTEXT. I tried SendMessageLong and SendMessage. EM_SETTEXTMODE always returns a zero(non-error). Can you shed some light on why this may not be working? Can you pop an RTB control(VB6) on a form and test this again?
Thank you
Hi
These days I am trying to figure out why I get another new line in a RTB when I save the contents to a file. This line is placed at the position around 68000. There are about 72000 characters in the RTB.
I tried with FileSave method and with Open command. In both cases result was the same.
Oh, one thing to add. The change is not visible immediately. The new line is there when the file is reopened.
If the file is opened with WordPad the new line is there.
Marko
I think its to late to answer but, maybe someone uses it , huh?
You can use UpTo method.
Richtextbox1.UpTo strSTRING
it search text and goes there if there is strSTRING in richtextbox1 text. if there is no text it goes to the end.
You must enable Vertical Scroll Bar , and then samply use
Richtextbox1.UpTo "§"
Note: "§"=CHR(245), i use it because , i know there is no "§" in my richtextbox control, you can use something like that who wouldnt write it to the richtextbox.
Sorry for my english
Keep in Peace...
EceL sTyLe
How can I format text that I'm adding to the box? IE, the program prints a string into the box, and I want to change the colour of some of the text in the string. Also how can I find the cursor's position and the character it's in front of?
i am very like this code. it prints all the text. but how can extract some line from rtf.
for e.g. print 26 lines each from the rtf text.
hi
how can i call another form from the current MDI child form
ebi
hi
we used pre printed paper for printing. so i want spilt the contents of RTF text and print it on multiple page on particular start line and end line
pls help me
ebi
hi
i also want the same thong for my application
if u find any answer how to do this plz let me know
thanks in anticapation
mtikoo
I am writing code for a connection routine and am using a rich text box to display the responses from the server. However as the text is added the user is constantly haveing to manually scroll the window to see the new text. I would like the program to automaically scroll the window for the user. Any help on this would be appreciated. thanks
I'm using VB6 - sp5 - -
This code absolutely does not work with my system..... I've been told that it's because the RichTextBox that comes with VB is an older version of the dll -----
Can I get it to work by replacing the RichEd dll?
If so, where can I get it?
how can inert image into richtextbox ?
I believe the problem for VB'ers is that the RichText control is from richtx32.ocx, which is based on riched32.dll. As per Microsoft ( http://msdn.microsoft.com/library/en-us/shellcc/platform/commctls/richedit/richeditcontrols/aboutricheditcontrols.asp ) this library only supports one level of undo. Later versions of riched (riched20.dll, etc.) allow for multiple levels, but I have found no Microsoft ocx that uses this library.
Bottom line, not going to happen using ONLY Richtext control, even with the correct messages sent to it.
As a side note, I found a few logic errors in above code...
1)
Public Property Get CanCopy() As Boolean
If rtb1.SelLength < 0 Then
CanCopy = True
End If
End Property
Should read as
Public Property Get CanCopy() As Boolean
If rtb1.SelLength > 0 Then
CanCopy = True
End If
End Property
2)
With richtx32.ocx, the above code will display the undo all the time. This is confusing during runtime. Really we only want it to show if there is no redo. This requires one of any number of possible revisions. Generate your favorite.
I believe the problem for VB'ers is that the RichText control is from richtx32.ocx, which is based on riched32.dll. As per Microsoft ( http://msdn.microsoft.com/library/en-us/shellcc/platform/commctls/richedit/richeditcontrols/aboutricheditcontrols.asp ) this library only supports one level of undo. Later versions of riched (riched20.dll, etc.) allow for multiple levels, but I have found no Microsoft ocx that uses this library.
Bottom line, not going to happen using ONLY Richtext control, even with the correct messages sent to it.
As a side note, I found a few logic errors in above code...
1)
Public Property Get CanCopy() As Boolean
If rtb1.SelLength < 0 Then
CanCopy = True
End If
End Property
Should read as
Public Property Get CanCopy() As Boolean
If rtb1.SelLength > 0 Then
CanCopy = True
End If
End Property
2)
With richtx32.ocx, the above code will display the undo all the time. This is confusing during runtime. Really we only want it to show if there is no redo. This requires one of any number of possible revisions. Generate your favorite.
Is it possible to highlight a word in a "rich text box" and add a link to that word?
For example in Microsoft Word you can highlight a word, click "insert" on the tool bar, select Hyperlink and add an url address to that word. This word can then be clicked on to go to that web page.
Is this possible in RTB?
Thanks
Chris
cgroves@lycos.co.uk
How do you autodetect URL's in VB? Not .net!
RichTextBOx1.SelectionFont.Bold
RichTextBOx1.SelectionFont.Underline etc are readonly
How to set the formating for the selected text???
Hi,
Can u please tell me, how to do this in VB.NET or C#. I need it urgently.
Thanx
Ashok
VB.net has introduced a number of changes to the way you access the RichTextBox's properties. SelUnderline, SelBold, SelStrikethrough etc are now available in the
richTextBox1.SelectionFont
property. For example, in VB.net, use
richTextBox1.SelectionFont.Underline
instead of
richTextBox1.SelUnderline
I will try to update the tutorial to be .net compliant in the next month or so.
but still can only undo level 1,why?can u tell me?thank you very much.
What o/s are you running? on Windows 2000/XP, the richtext box has been "upgraded" to include multiple undo/redo.. otherwise, you'll probably be left with the old single undo/redo..
i expirienced the same thing... does anyone have a working example on this?
After using this code the undo level is still 1.
Can someone help me out ?
Thank you !
This thread is for discussions of RichTextBox Control.