Q160233: FIX: Can’t Set SelStart Property of RichTextBox to > 32K

Article: Q160233
Product(s): Microsoft Visual Basic for Windows
Version(s): 
Operating System(s): 
Keyword(s): kbGrpDSVB
Last Modified: 11-JAN-2001

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The information in this article applies to:

- Microsoft Visual Basic Standard Edition, 32-bit, for Windows, version 4.0 
- Microsoft Visual Basic Professional Edition, 32-bit, for Windows, version 4.0 
- Microsoft Visual Basic Enterprise Edition, 32-bit, for Windows, version 4.0 
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SYMPTOMS
========

You cannot set the SelStart property of RichTextBox controls that contain text
greater than 32K (32768) characters in length to a value greater than 32767 and
less than the text length. Although this is a legal range, SelStart is
automatically set to the text length. Consequently, you cannot make selections
within this range.

STATUS
======

Microsoft has confirmed this to be a bug in the Microsoft products listed at the
beginning of this article. This bug has been fixed in Visual Basic 5.0.

RESOLUTION
==========

Use the SendMessage API of USER32 with the EM_EXSETSEL parameter to set the
SelStart position:

     Private Const WM_USER = &H400
     Private Const EM_EXSETSEL = (WM_USER + 55)

     Private Declare Function SendMessage Lib "USER32" Alias "SendMessageA"
     (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, lParam As
     Long) As Long

     Private Sub Command1_Click()
     Dim x As String

         x = String(32800, "a")
         RichTextBox1.Text = x

         '''[THE NORMAL WAY] RichTextBox1.SelStart = 32790
         SendMessage RichTextBox1.hwnd, EM_EXSETSEL, 0, 32790
         RichTextBox1.SelLength = 10

         MsgBox RichTextBox1.SelText

     End Sub

MORE INFORMATION
================

Steps to Reproduce Problem
--------------------------

1. Start a new project in Visual Basic. Form1 is created by default.

2. Place a RichTextBox, RichTextBox1, on Form1.

3. Place a CommandButton, Command1, on Form1.

4. Place the following code in the Click event of Command1:

     Private Sub Command1_Click()
     Dim x As String

         x = String(32800, "a")
         RichTextBox1.Text = x

         RichTextBox1.SelStart = 32790
         RichTextBox1.SelLength = 10

         MsgBox RichTextBox1.SelText

     End Sub

5. Press the F5 key to run the project.

6. Click Command1 and note that nothing is selected.

Additional query words: kbstream kbVBp400bug kbVBp500fix kbVBp kbdsd kbDSupport kbControl

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Keywords          : kbGrpDSVB 
Technology        : kbVBSearch kbAudDeveloper kbVB400Search kbVB400
Issue type        : kbbug
Solution Type     : kbfix

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