I'm having an issue referencing public procedures of User Controls that I've created within a VB6 project.
A simple example (exe), I have a form with a button and a user control:
Option Explicit
Private Sub Command1_Click()
UserControl1.updateMessage ("TIME NOW: " & DateTime.Time)
End Sub
The User Control code is as follows:
Option Explicit
Public Sub updateMessage(ByVal newMessage As String)
Label1.Caption = newMessage
End Sub
This exe compiles and works fine, and when I'm typing updateMessage in the Form, it appears in the intellisense list with the appropriate requirements. The issue I have is when I'm wanting to "go to the definition" of updateMessage, instead of going to the appropriate section of the code within the User Control, the message always returns with:
"Cannot jump to 'updateMessage' because it is in the library 'Unknown1' which is not currently referenced."
where the numbered suffix of "Unkown1" changes from time to time.
It seems that if there were no reference to this procedure, then it would not appear in the intellisense and the project shouldn't compile. When running this with MZTools (though the error appears regardless of this plug-in being installed), I can go into the updateMessage procedure, and use it to find all procedures calling this function, so the link between the two should exist (although I'm not sure if MZTools just finds using a text-matching pattern).
If anyone out there could shed some light on this matter, it would be very much appreciated, and save this poor VB6 developer a lot of hassle!
I have SP6 installed (build 9782) of VB6 and am running XP SP3 on an HP dx2400.
Yes, this is extremely annoying and I'm convinced it's a bug in VB6. I say this because, if you locate the updateMessage method in the object browser and double-click on it, you are taken to the definition. So, the compiler actually does know where the definition is, it just refuses to take you there with Shift+F2.
Related
I have a VB6 app that has a ton of 3rd party components. The app works well, but on exit (and only when running as a standalone EXE, e.g. not in the IDE), it pops up an error message:
I've seen errors like these before but typically it says which component is missing dependencies or is not registered properly.
I ran it through Process Monitor and got the following files that it cannot find:
And then it quits. I googled the file names that it cannot find and can't seem to find anything. It seems like its searching for a variation of MSComENU, MSComEN and MSCOENU dlls.
I checked and rechecked to make sure that all the the 3rd party components are there and they are - the application functions fine, it wouldn't if they weren't there.
It is worth noting that error occurs after the last line of VB6 code (in Form_Unload event) has fired. I know this because the last line is a message box that does appear.
Much, much later EDIT: I finally got back to dealing with the problem and figured it out by process of elimination (and it was a loooong process). In the end it had nothing to do with any MSCOMM*.dll entries. In fact, I do not know why they still show up in Process Monitor. The problem was much simpler.
I had several 3rd party controls on the main form. In an effort not to pollute the main form with a ton of event handling code, I delegated these controls to a new class, like so:
' declaration code in main form'
Private WithEvents moDelegateObject as clsDelegateObject
' still in the main form, after initialization'
Set moDelegateObject = new clsDelegateObject
With moDelegateObject
Set .ThirdPartyCtlHandler1 = me.ThirdPartyCtl1
Set .ThirdPartyCtlHandler2 = me.ThirdPartyCtl2
Set .ThirdPartyCtlHandler3 = me.ThirdPartyCtl3
end with
' declarations and properties inside of clsDelegateObject'
Private WithEvents moThirdPartyCtlHandler1 as ThirdPartyCtl
Private WithEvents moThirdPartyCtlHandler2 as ThirdPartyCtl
Private WithEvents moThirdPartyCtlHandler3 as ThirdPartyCtl
Public Event FooEvent() ' other various events as well '
Public Property Set ThirdPartyCtlHandler1(o as ThirdPartyCtl)
moThirdPartyCtlHandler1 = o
End Property
Public Property Get ThirdPartyCtlHandler1() as ThirdPartyCtl
ThirdPartyCtlHandler1 = moThirdPartyCtlHandler1
End Property
' ... Repeat for each handler ...'
What was missing was code to explicitly deallocate these objects prior to closing. This is something that Visual Basic typically does. So I added the following in the Form_QueryClose in the main form:
With moDelegateObject
Set .ThirdPartyCtlHandler1 = Nothing
Set .ThirdPartyCtlHandler2 = Nothing
Set .ThirdPartyCtlHandler3 = Nothing
End with
Set moDelegateObject = Nothing
Last line turned out to be superflous, but I threw it in there for completeness sake. I think it was a combination of delegating controls to a delegate class and receiving events from it in the Main form and using a good number of really obscure 3rd party controls which contributed to this problem. It is probable that the 3rd party control does not cleanly deallocates itself. Anyway, lesson learned.
This could be a DLL_PROCESS_DETACH or CoUninitialize problem. Raymond Chen's blog "The Old New Thing" has a couple of relevant articles:
When DLL_PROCESS_DETACH tells you that the process is exiting, your best bet is just to return without doing anything
Do you know when your destructors run? Part 1.
Quick overview of how processes exit on Windows XP
How you might be loading a DLL during DLL_PROCESS_DETACH without even realizing it
The thread that gets the DLL_PROCESS_DETACH notification is not necessarily the one that got the DLL_PROCESS_ATTACH notification
As you said these are 3rd party components. You could try to make smaller test cases until the problem disappears to pinpoint the buggy component. You could also try a native code debugger and analyze what code created the error message.
The simplest solution however to work around the issue is trying to force a specific load-order of all those components. In the Main() or startup form, try to use some functionality of each 3rd party component in a fixed order. If the bug still appears, change the order until the problem vanishes. That might work.
You could try using dependency walker on the list of references in the project file to see if any of those third party files are missing dependencies. If no dependencies are missing then try registering the files again using regsvr32. If any of the regsvr32 commands fail then you may have found the component with missing dependencies.
I have an MFC application that uses an ancient (circa 1999) third-party ActiveX control.
Since upgrading the project from VS2008 to VS2010, I'm having problems...
In the OnSize handler of the parent dialog IsWindow always returns false for the handle returned by control.GetSafeHwnd(), even when GetSafeHwnd() returns a non-NULL value. The rest of the control's parent dialog is displayed fine, but it doesn't seem to respond to any input.
I've seen this article, but GetSafeHwnd() isn't returning NULL in this case (after the first time that it is called, which is before the control is instantiated).
The control does cause the trace message "Control wants to be windowless" to be output when it's loaded. However it also does this when compiled in VS2008, so this may be a red herring. Searching for this message points me to creating a class derived from COleControlSite, and denying the control windowless-ness, but it seems there are no good example of this available, and as I say, it's not clear that this is really the cause of the problem.
I've also found this issue mentioned on MSDN's VS2010 porting page:
"An ActiveX control compiled by using Visual C++ 6.0, when embedded in
a dialog box in a project developed by using Visual C++ 2010, may
cause your program to assert at run time. In this situation, open the
ATL or MFC project associated with the ActiveX control in Visual C++
2010, and recompile it.. The assert will be in the file occcont.cpp,
on this line in source: ASSERT(IsWindow(pTemp->m_hWnd))."
I assume that there's something about VS6-compiled ActiveX controls that causes the window handles to be treated as invalid by the current Win32 implementation of IsWindow. The suggested solution is of course unhelpful as it's a third-party control, and we can't recompile it.
Has anyone managed to get around this?
I've already found solutions for VS2010 projects not running on Windows 2000, and errors linking to ODBC, but don't seem to be able to find anything on this one.
Thanks,
Chris
I didn't find a solution to this in the end - upgraded the controls to a VS2010-compatible version.
For what it's worth: if you don't care whether the control will appear transparent or not, you may force the control to have a window anyway - even though it can operate without a window.
You see, the ActiveX control must first ask the container (the window which will host the control) if it's okay to be activated without a window. This is simply because not all containers support windowless activation.
If this interface (IOleInPlaceSiteWindowless) returns okay then it proceeds with this special windowless activation, if not a window will be created for the control as normal.
Disclaimer:
I don't know if this 'unnecessary' window will make the assertion failure go away. In other words: I don't know if the window handle is passed down 'deep' enough into the AX control.
More about the IOleInPlaceSiteWindowless interface:
https://msdn.microsoft.com/en-us/library/windows/desktop/ms682300(v=vs.85).aspx
I have a VB6 application, the installer is compiled using INNO Setup.
The installer runs fine. But in about 10% of computers when the user clicks the Icon to run the installed app, it doesn't start, no error message, only a Beep sound.
This is happening on XP and also Win 7.
I develop in XP and Win 7 and the application works OK, so I haven't been able to reproduce the issue.
The installer registers all ocx and dlls needed (afaik). (Well not completely all, it assumes MS run-time components should be there, but I guess an error message should show up if something is missing)
I was thinking some kind of user permissions, UAC, but even users in the admin group have had the issue.
Could you point me to what possible issues to look for and test in order to patch the app.
Thanks!
[FOLLOW UP]
Thanks to the tips, found out the manifest is causing the problem. I use it to make the controls look better:
http://www.vbaccelerator.com/home/vb/code/libraries/xp_visual_styles/using_xp_visual_styles_in_vb/article.asp
Now I'm trying to discover why. I have another application with the same manifest and that one works ok.
Haven't been able to get feedback on the event viewer yet.
The "beep crash" often points to an error in an application manifest such as an XML syntax error or namspace conflict. Event Logs will often provide a hint about this.
But I've found that people often try to use the Common Controls 6.0 Library without ensuring proper library loading sequence.
Before any Forms are openend you should load shell32 and then comctl32. The easiest way is a couple of no-op calls in Sub Main:
Option Explicit
Private Declare Sub InitCommonControls Lib "comctl32" ()
Private Declare Function IsUserAnAdmin Lib "shell32" () As Long
Private Sub InitCommonControlsVB()
IsUserAnAdmin
InitCommonControls
End Sub
Private Sub Main()
InitCommonControlsVB
Form1.Show
End Sub
Without this your program will usually work fine in Vista or Win7, but will fail on some XP service pack and patch levels. Part of this is due to changes over time in the Fusion subsystem that handles SxS activation and comctl32.dll patches.
Ignore those saying you need to call InitCommonControlsEx(), it isn't necessary unless you are constructing and using Win32 controls directly instead of VB6 and COM controls.
A few things to try to narrow it down:
Check the Windows Event Log for crash events
Check the Windows Event Log (in the Application section) for crash reports from your application. You can quickly get to the log viewer on Windows XP by clicking Start > Run, typing eventvwr and pressing Enter. On Windows 7, you can type "event viewer" in the search box that is in the Start menu. You can filter the events to only show error events from your program.
You might find a few error events on one of the computers where this problem has already occured, because it sounds like the error reporting feature is turned off on these computers (in which case "hard crashes" like access violations are logged in the Event Log instead of displaying an error dialog to the end-user, as long as a debugger isn't installed on the computer).
Make sure "Error Reporting" is turned at the OS level
As mentioned in the previous section, it sounds like the error reporting feature is turned off on these computers. In that case, a crash won't display any kind of message to the end-user at all and the application will just vanish suddenly. In Windows XP, you can check this setting (and turn it on) as follows:
Right-click "My Computer" and select Properties.
Open the Advanced tab and click the Error Reporting button.
Select the Enable Error Reporting option.
Click OK to all the open windows.
Add trace code to your application
You could also add some trace code to your application's start-up code, such as code to display a message box or write a message to the Windows Event Log or to a log file as soon as your application starts (for example, in the Form_Initialize event of your main form, or in a Sub Main routine).
This way you will be able to tell whether your application is crashing before or after the VB6 runtime is loaded: if you try to start the application and it disappears/crashes, and your startup message isn't logged, then you know it's crashing before it even has a chance to get to your application's startup code, which could indicate that a dependency of the VB6 runtime or the VB6 runtime itself is not installed properly.
Note that Windows XP and Windows 7 both ship with the VB6 runtime pre-installed, but it's possible for misbehaving installers to overwrite or remove files that are part of the VB6 runtime.
We have a legacy VB6 application which has worked just fine on Windows XP Professional SP 3 until just recently when we added an IE frame control so that we could display static local HTML files on a form. And, it works fine until I go to close the application. And, then it reports the following error message (consistently):
Faulting module ntdll.dll, version 5.1.2600.5755, stamp 49901d48
Here's the reference in the Visual Basic project file:
Object={EAB22AC0-30C1-11CF-A7EB-0000C05BAE0B}#1.1#0; ieframe.dll
And we use it by performing the following actions:
Development machine is running Win7 + Vb6 IDE.
Add a component reference to the "Microsoft Internet Controls" located at C:\Windows\SysWow64\ieframe.dll
Place a control on the form at design time.
Show that form modally by calling Form.Show vbModal The error happens when I use the default form instance frmMyForm.Show vbModal as well as when I use a local instance Dim MyForm as New frmMyFormMyForm.Show vbModal
Call WebBrowser.Navigate "staticPage.html"
When the user presses a button, the button click event returns the user choice and the form is disposed of.
Exit the application -- Here's where I get the error.
I've been looking all over the web, and haven't been able to find a whole lot of people still trying to use VB6 in this way. So, I'm wondering if someone might be able to help me on stackoverflow. Any help is much appreciated!
[Update] And, the plot thickens. I made a sample application with just that web component in order to make sure that it was causing the error. But, I didn’t experience the error when it closed like I was when exiting our existing/legacy vb6 application. I'll do a bit more investigating.
A follow up to this in case any runs into the same issue (the original poster and I were coworkers at the time)...
The application was using the VBCorLib library, and some of its string manipulation classes utilized direct memory access incorrectly. Read more at this VBCorLib forum post.
It turns out that the issue was that I was trying to delete the temporary file that the browser had loaded. It works now that I've moved that delete file code to the form unload event.
My project has both client and server components in the same solution file. I usually have the debugger set to start them together when debugging, but it's often the case where I start the server up outside of the debugger so I can start and stop the client as needed when working on client-side only stuff. (this is much faster).
I'm trying to save myself the hassle of poking around in Solution Explorer to start individual projects and would rather just stick a button on the toolbar that calls a macro that starts the debugger for individual projects (while leaving "F5" type debugging alone to start up both processess).
I tried recording, but that didn't really result in anything useful.
So far all I've managed to do is to locate the project item in the solution explorer:
Dim projItem As UIHierarchyItem
projItem = DTE.ToolWindows.SolutionExplorer.GetItem("SolutionName\ProjectFolder\ProjectName").Select(vsUISelectionType.vsUISelectionTypeSelect)
(This is based loosely on how the macro recorder tried to do it. I'm not sure if navigating the UI object model is the correct approach, or if I should be looking at going through the Solution/Project object model instead).
Ok. This appears to work from most UI (all?) contexts provided the solution is loaded:
Sub DebugTheServer()
DTE.Windows.Item(Constants.vsWindowKindSolutionExplorer).Activate()
DTE.ActiveWindow.Object.GetItem("Solution\ServerFolder\ServerProject").Select(vsUISelectionType.vsUISelectionTypeSelect)
DTE.Windows.Item(Constants.vsWindowKindOutput).Activate()
DTE.ExecuteCommand("ClassViewContextMenus.ClassViewProject.Debug.Startnewinstance")
End Sub
From a C# add-in, the following worked for me:
Dte.Windows.Item(Constants.vsWindowKindSolutionExplorer).Activate();
Dte.ToolWindows.SolutionExplorer.GetItem("SolutionName\\SolutionFolderName\\ProjectName").Select(vsUISelectionType.vsUISelectionTypeSelect);