Q143044: INFO: How Visual Basic 4.0 Handles Files Marked Read-Only
Article: Q143044
Product(s): Microsoft Visual Basic for Windows
Version(s): WINDOWS:4.0;
Operating System(s):
Keyword(s): kbenv kbVBp400 kbGrpDSVB
Last Modified: 04-MAY-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, 16-bit, for Windows, version 4.0
- Microsoft Visual Basic Professional Edition, 32-bit, for Windows, version 4.0
- Microsoft Visual Basic Enterprise Edition, 16-bit, for Windows, version 4.0
- Microsoft Visual Basic Enterprise Edition, 32-bit, for Windows, version 4.0
- Microsoft Visual SourceSafe, 16-bit, for Windows, version 4.0
- Microsoft Visual SourceSafe, 32-bit, for Windows 4.0
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SUMMARY
=======
Visual Basic 4.0 may handle files with the read-only attribute set differently
than Visual Basic 3.0. This may result in a "Can't Edit Module" error when
trying to change a code module. The Visual Basic 4.0 development environment
will handle read-only files in one of two ways. The way Visual Basic 4.0 behaves
is dependent on the current setting of the ReadOnlyMode property of the
development environment. If the ReadOnlyMode is set to 0 (lenient) you will be
able to edit files marked read-only just like Visual Basic 3.0. Of course you
will still not be able to save your changes. If the ReadOnlyMode is set to 1
(strict) Visual Basic will not allow you to edit files marked read-only.
MORE INFORMATION
================
The default ReadOnlyMode for Visual Basic 4.0 is lenient. However, the default
can be changed to strict by adding ReadOnlyMode=1 to the Visual Basic section of
the VB.INI.
ReadOnlyMode can also be changed dynamically by Visual Basic 4.0 add-ins through
the ReadOnlyMode property of the Application object of Visual Basic 4.0 add-in
object model. The Microsoft SourceSafe add-in for Visual Basic 4.0 sets Visual
Basic 4.0 to the strict mode. The following example shows you how to create a
add-in that will allow you to toggle the ReadOnlyMode from a menu item.
Example
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1. Start a new project.
2. Remove the default Form1.
3. Add a reference to "Microsoft Visual Basic 4.0 Development Environment" using
the Tools/References dialog.
4. Add a new standard module (Module1.BAS by default).
5. Put the following code in the standard module:
''' MODULE1.BAS
'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
#If Win16 Then
Declare Function WritePrivateProfileString Lib "KERNEL" ( _
ByVal AppName As String, ByVal KeyName As String, _
ByVal keydefault As String, ByVal FileName As String) As _
Integer
Declare Function GetPrivateProfileString Lib "KERNEL" ( _
ByVal AppName As String, ByVal KeyName As String, _
ByVal keydefault As String, ByVal ReturnString As String, _
ByVal NumBytes As Integer, ByVal FileName As String) As Integer
#ElseIf Win32 Then
Declare Function WritePrivateProfileString Lib "KERNEL32" _
Alias "WritePrivateProfileStringA" (ByVal AppName As String, _
ByVal KeyName As String, ByVal keydefault As String, _
ByVal FileName As String) As Long
Declare Function GetPrivateProfileString Lib "KERNEL32" _
Alias "GetPrivateProfileStringA" (ByVal AppName As String, _
ByVal KeyName As String, ByVal keydefault As String, _
ByVal ReturnString As String, ByVal NumBytes As Long, _
ByVal FileName As String) As Long
#End If
Sub Main()
#If Win16 Then
Const Section = "Add-Ins16"
#ElseIf Win32 Then
Const Section = "Add-Ins32"
#End If
Const BufSize = 255
Dim Ret As Variant
Dim RetStr As String
' Check to see if the entry is already in the VB.INI file.
' Add if not.
RetStr = Space(BufSize)
Ret = GetPrivateProfileString(Section, "ReadOnlyMode.Switch", _
"NotFound", RetStr, BufSize, "VB.INI")
RetStr = Left(RetStr, Ret)
If RetStr = "NotFound" Then
WritePrivateProfileString Section, "ReadOnlyMode.Switch", _
"0", "VB.INI"
End If
End Sub
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
6. Add a new class module to the project (Class1.CLS by default.)
7. Set the following properties of the class module to the specified values:
Property Value
---------------------------------------
Instancing 1 - Creatable MultiUse
Name Switch
Public True
8. Put the following code in the class module:
''' CLASS1.CLS
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
Option Explicit
Private ThisInstance As VBIDE.Application
Private AddInMenuLine As VBIDE.MenuLine
Private AddInID As Long
Public Sub ConnectAddIn(VBInstance As Object)
Set ThisInstance = VBInstance
Set AddInMenuLine = ThisInstance.AddInMenu.MenuItems.Add( _
"Strict &ReadOnlyMode")
AddInMenuLine.Checked = ThisInstance.ReadOnlyMode
AddInID = AddInMenuLine.ConnectEvents(Me)
End Sub
Public Sub DisconnectAddIn(Mode As Integer)
AddInMenuLine.DisconnectEvents AddInID
ThisInstance.AddInMenu.MenuItems.Remove AddInMenuLine
End Sub
Public Sub AfterClick()
ThisInstance.ReadOnlyMode = ThisInstance.ReadOnlyMode Xor 1
AddInMenuLine.Checked = ThisInstance.ReadOnlyMode
End Sub
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
9. Set the following Project Options:
Option Value
----------------------------------------
Startup Form Sub Main
Project Name ReadOnlyMode
StartMode OLE Server
Error Trapping Break in Class Module
10. Save the project.
11. Run the project.
12. Start up a second instance of Visual Basic (Form1 is created by default.)
13. Use the Add-In Manager to add the ReadOnlyMode.Switch add-in.
14. Open a code module with that has the read-only attribute set. You can tell
if a file is marked read-only by the small red lock that appears in the
project window next to the file.
15. From the Add-In menu you can switch the ReadOnlyMode. When checked the
environment will be in strict mode and when unchecked it will be in lenient
mode.
Additional query words: Addin Addins VBIDE ssafe
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Keywords : kbenv kbVBp400 kbGrpDSVB
Technology : kbVBSearch kbSSafeSearch kbAudDeveloper kbVB400Search kbVB400 kbVB16bitSearch kbSSafe400 kbSSafe16bitSearch kbSSafe32bitSearch
Version : WINDOWS:4.0;
Issue type : kbinfo
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