Q284948: BUG: Text Containing Single LF or CR Becomes CR/LF on Win2000
Article: Q284948
Product(s): Microsoft Visual Basic for Windows
Version(s): 6.0
Operating System(s):
Keyword(s): kbother kbOSWin2000 kbVBp kbVBp600 kbGrpDSVB kbDSupport kbCodeSnippet kbWin2000PreSP3Fi
Last Modified: 15-AUG-2002
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The information in this article applies to:
- Microsoft Visual Basic Enterprise Edition for Windows, version 6.0, used with:
- the operating system: Microsoft Windows 2000
- Microsoft Visual Basic Professional Edition for Windows, version 6.0, used with:
- the operating system: Microsoft Windows 2000
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SYMPTOMS
========
If you assign text that contains a single line feed character (LF, which is
ASCII Character 10) or a single carriage return character (CR, which is ASCII
Character 13) to the RichTextBox control, the text is modified when Riched20.dll
processes the EM_STREAMIN and EM_STREAMOUT messages to include both a carriage
return and line feed character (CR/LF).
This behavior only occurs on Windows 2000 and has changed (and thus regressed)
since Microsoft Windows NT 4.0 Service Pack 6 (SP6). In Windows NT 4.0 SP6, the
text remains unmodified.
RESOLUTION
==========
To resolve this problem, obtain the latest service pack for Windows 2000. For
additional information, click the following article number to view the article
in the Microsoft Knowledge Base:
Q260910 How to Obtain the Latest Windows 2000 Service Pack
The English-language version of this fix should have the following file
attributes or later:
Date Time Version Size File name
-------------------------------------------------------
4/16/2001 04:31p 5.30.23.1207 412,432 Riched20.dll
STATUS
======
Microsoft has confirmed that this is a problem in the Microsoft products that
are listed at the beginning of this article. This problem was first corrected in
Windows 2000 Service Pack 3.
MORE INFORMATION
================
For additional information about how to obtain a hotfix for Windows 2000
Datacenter Server, click the article number below to view the article in the
Microsoft Knowledge Base:
Q265173 The Datacenter Program and Windows 2000 Datacenter Server Product
For additional information about how to install multiple hotfixes with only one
reboot, click the article number below to view the article in the Microsoft
Knowledge Base:
Q296861 Use QChain.exe to Install Multiple Hotfixes with One Reboot
Steps to Reproduce Behavior
---------------------------
Scenario 1:
1. On a Windows 2000-based computer, open Visual Basic 6.0.
2. Create a new Standard EXE project with the sample code that is provided in
the following Microsoft Knowledge Base article:
Q146022 HOWTO: Set Up the RichTextBox Control for WYSIWYG Printing
3. Run the project, and load a Unix-formatted TextFile, which uses LF characters
only. Under Windows 2000, an infinite loop occurs in the following section of
code:
' Get length of text in RTF.
TextLength = Len(RTF.Text)
' Loop printing each page until done.
Do
' Print the page by sending EM_FORMATRANGE message.
NextCharPosition = SendMessage(RTF.hWnd, EM_FORMATRANGE, True, fr)
If NextCharPosition >= TextLength Then
Exit Do 'If done then exit
End If
fr.chrg.cpMin = NextCharPosition ' Starting position for next page
fr.hdc = Printer.hdc
fr.hdcTarget = Printer.hdc
Loop
SendMessage seems to be operating on the original, unconverted data, while the
Len function returns results based on the CR/LF pairs.
Scenario 2:
1. On a Windows 2000-based computer, open Visual Basic 6.0.
2. Create a new Standard EXE project. Form1 is created by default.
3. From the Project menu, select Components. In the resultant dialog box, select
the "Microsoft RichTextBox Control" check box, and then click OK. A
RichTextBox icon appears on the controls Toolbox on the left.
4. Place a RichTextBox control on Form1.
5. Double-click on Form1 to bring up the code window. Add the following code to
Sub Form_Load:
Dim str As String
Dim strLastChar As String
Dim strSecondToLastChar As String
RichTextBox1.Text = "Item" & Chr(10)
' Cache the richtext string.
'
str = RichTextBox1.Text
' Pull the last and second to last characters.
'
strLastChar = Right(str, 1)
strSecondToLastChar = Mid(str, Len(str) - 1, 1)
' Display the string length and ASCII.
'
MsgBox Len(RichTextBox1.Text) & " " & Asc(strSecondToLastChar) _
& " " & Asc(strLastChar)
6. Press the F5 key to run the project. The message box displays "6 13 10". The
string is 6 characters long and ends in an ASCII 13 (carriage return) and
ASCII 10 (line feed) combination. This means that an ASCII 13 character
(carriage return) is inserted into the string either at the time the text is
set or before it is returned by Riched20.dll.
On Windows NT 4.0 SP6, the string "5 109 10" is returned. The string is 5
characters long and ends in an ASCII 109 "m" and ASCII 10 (line feed) character
combination.
Scenario 2 becomes more problematic in the following case:
1. Close Form1 to stop the project.
2. Replace the Form_Load code with the following code:
RichTextBox1.Text = "Item" & Chr(10)
RichTextBox1.Span Chr(10), , True
MsgBox Len(RichTextBox1.SelText)
3. Press F5 to run the project. SelText has a length of 6 characters: the "Item"
string, followed by a carriage return and line feed. On Windows NT 4.0 SP6,
the return string contains the 4 characters, "Item", as expected.
Additional query words: kbOther RichEdit Riched20
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Keywords : kbother kbOSWin2000 kbVBp kbVBp600 kbGrpDSVB kbDSupport kbCodeSnippet kbWin2000PreSP3Fix kbWin2000sp3fix
Technology : kbVBSearch kbAudDeveloper kbZNotKeyword6 kbZNotKeyword2
Version : :6.0
Issue type : kbbug
Solution Type : kbfix
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