I have a custom class in VBA that pulls historical data from Bloomberg. The class, and the Bloomberg objects it uses, are asynchronous and based on the RTD platform.
The issue I'm having is that I run Subs that call this custom class, but the event handling code in the custom class only runs once my Sub is finished.
Dim bbHist As New HistDataControl
Sub PullDataAndDoStuff()
bbHist.MakeHistRequest StockTicker, "MOV_AVG_50D", startDate, Date
Call DoStuffWithTheData
End Sub
Private Sub DoStuffWithTheData()
..... 'None of this works, because MakeHistRequest / bbHist class hasn't run
End Sub
Is there a way to force Excel to wait until the bbHist has run?
If it has a property to check to see if it's done, then you can just put a DoEvents in a Do Until loop, checking that property for its completion.
The problem is that the bbg handler waits.
So the solution is to make your sub wait for the bbg query to end, and then call your processing data sub.
There are plenty of solutions for that on stackoverflow so I'll let you look for that.
Related
I am working on a very large VBA project in Excel at my job. We are about 1500 lines of code for just one feature and have about a dozen more features to add. Because of this, I've been trying to break everything down so that I can keep code for each feature in separate places. OOP sucks in VBA... The problem being that these controls MUST have events fired. Of course, some events (like the TextBox_AfterUpdate event) are not available when you dynamically create controls. It's a bit convoluted because of everything that is going on, so I'll break it down the best I can:
I have a class module that represents a tab for a multipage control. When a user clicks on a tab, the Userform calls this class module and THERE I have the controls created dynamically. This way I can keep the code in that class module. I have a sub that I deemed as the "AfterUpdate" sub and put code that I needed to run there. Now the problem is to get that sub to be called at the appropriate time.
So what I did is to set up a Timer of sorts to check and see if the "ActiveControl" is said textbox. If it is not, we can assume that focus has left and we can raise that event. Here's the code I'm using:
An abbreviated version of the tab creation...
Private WithEvents cmbMarketplace As MSForms.ComboBox
Public Sub LoadTab(ByVal oPageTab As Object)
If TabLoaded Then Exit Sub
Set PageTab = oPageTab
Dim tmp As Object
Set tmp = PageTab.Add("Forms.Label.1")
tmp.Top = 6: tmp.Left = 6: tmp.Width = 48
tmp.Caption = "Marketplace:"
Set cmbMarketplace = PageTab.Add("Forms.ComboBox.1", "cmbMarketplace")
' LOAD OTHER CONTROLS '
TabLoaded = True
Start_Timer
End Sub
Then Start_Timer:
Public Sub Start_Timer()
TimerActive = True
Application.OnTime Now() + TimeValue("00:00:01"), "Timer"
End Sub
And the sub that is to be fired:
Public Sub Timer()
If TimerActive Then
' DO SOME RANDOM THINGS '
Application.OnTime Now() + TimeValue("00:00:01"), "Timer"
End If
End Sub
Does this seem like a reasonable approach to solving the problem I'm facing? I'm open to suggestions...
That's the first problem. This seems like a lot of work to accomplish this. (I'm working on getting visual studio, but I don't know if that's going to happen)
The above code will work but the "Timer" sub will not get raised at all. I get no errors if I just run the code. Everything is created, everything works as I would hope. However, if I step through the code, I eventually will get the following error:
Cannot run the macro "...xlsm!Timer". The macro may not be available in this workbook or all macros may be disabled.
Obviously neither of those suggestions are valid. Macros ARE enabled and the sub is in the same darn class module. I tried making it public, same problem. Tried "ClassModule1!Timer" to no avail. I'm at my wits end trying to figure this out. Thinking of having people write ALL this in the Userform or just giving up.
Does anybody have any suggestions on how to effectively break up large chunks of code? And does anybody have a clue why this sub will not run and seemingly cannot be found?
I understand that this is a confusing situation, so if you need more info or code examples or want to know why I have something set up the way I do, let me know.
Thanks!
Obviously neither of those suggestions are valid. Macros ARE enabled and the sub is in the same darn class module.
There's the problem: a macro cannot be in a class module. The message is entirely correct: VBA cannot see the Timer procedure, because it's not accessible.
A class module is a blueprint for an object, VBA (or any OOP language for that matter) can't do anything with a class module, without an instance of that class - i.e. an object.
Your timer callback needs to be a Public Sub in a standard module, so that it can be called directly as a macro. Public procedures of a class modules are methods, not macros.
Depending on what ' DO SOME RANDOM THINGS ' actually stands for, this may or may not require some restructuring.
1500-liner spaghetti code can be written in any language BTW.
I have a bug in my application which is the same as here which this person was running into the same problem. My application is multi threaded where the worker thread is updating the Waveformgraph on the UI. I believe that is where my problem is and why, periodically, and on occassion I get a big red X in at least one of my waveformgraph objects when running the application. From reading and research, I need to use an Invoke or BeginInvoke method? Can someone please explain better and provide a sample code that is relevant to my code? The samples that I've found so far still have me hazy on how I need to do this or what I need to do. Thank you for your help.
This code is on the swScopeOnOff click event, main thread.
thread2 = New System.Threading.Thread(AddressOf dataAcquiring)
thread2.Start()
This code is in dataAcquiring Sub
Public Sub dataAcquiring()
'While Scope switch is on, stream each Ai channel's data continuously to its respective WaveForm graph
Do While swScopeOnOff.Value = True
data = reader.ReadWaveform(readRate)
i = 0
For Each WaveformGraph In WFGS
WaveformGraph.PlotWaveformAppend(data(i)) 'This line is updating the UI's waveform graphs
i += 1
Next
i = 0
Loop
End Sub
Proper, thread-safe invocation is actually not as hard as one might think (not even for thread-safe events, but that's irrelevant for this question).
I would recommend you to use the normal Invoke method, such as Me.Invoke() (where Me is the current form, if not, use Form1 or whatever it's called instead). Using BeginInvoke() may be asynchronous but it stacks memory usage and can cause memory leaks if EndInvoke() is not called correctly.
If you target .NET 4.0 or higher you can simply do like this:
Me.Invoke(Sub() WaveformGraph.PlotWaveformAppend(data(i)))
However if you target .NET 3.5 or lower it requires a few more lines of code.
'Outside your Sub.
Delegate Sub WaveformAppendDelegate(ByRef WaveformGraph, ByRef data)
'Create a new sub.
Public Sub AppendData(ByRef WaveformGraph, ByRef data)
WaveformGraph.PlotWaveformAppend(data)
End Sub
'Inside your sub, when you're going to invoke.
Me.Invoke(New WaveformAppendDelegate(AddressOf AppendData), WaveformGraph, data(i))
I need to be able to pass the thread name into a subroutine in order to abort it when I need to.
So I have this so far:
Dim BrowserSpawn As New System.Threading.Thread(AddressOf BrowserSub)
BrowserSpawn.Start()
Private Async Sub BrowserSub(BrowserSpawn)
...
End Sub
Because the subroutine creates a browser within Form1 groups I needed to invoke access to these controls within the sub.
Note: This works fine when I'm not passing in the thread name.
If Me.GroupNamehere.InvokeRequired Then
Me.GroupNamehere.Invoke(New MethodInvoker(AddressOf BrowserSub))
Else
'Do nothing
End If
When I'm passing in the thread name these become a problem when trying to compile:
Method does not have a signature compatible with delegate 'Delegate Sub MethodInvoker()'.
I'm hoping this is just a syntax thing but I can't seem to get it to work. Is there any way I'm able to pass in this thread name without breaking my invokerequired check?
If I try and change it to the obvious:
Me.GroupNamehere.Invoke(New MethodInvoker(AddressOf BrowserSub(BrowserSpawn)))
It tells me Addressof operand must be the name of a method (without parentheses). Although without the parentheses it's not happy either so I don't know where to go from here.
/edit:
Stumbled across How can I create a new thread AddressOf a function with parameters in VB?
Which seems to confirm what I was trying passing something like:
Private Sub test2(Threadname As Thread)
' Do something
End Sub
And the sub seems happy with that. But I'm not sure how to do that without breaking the invoker part.
Me.GroupNameHere.Invoke(New MethodInvoker(AddressOf SubNameHere))
Works normally. If SubNameHere() becomes SubNameHere(threadname as thread) then that seems happy enough but the invoke line breaks and doesn't want more than the address of.
Two slight syntax changes sorted it:
Private Async Sub SubName(ThreadNameAs Thread)
and
GroupName.Invoke(New MethodInvoker(Sub() Me.SubName(ThreadName)))
This is probably the dumbest question I've ever asked here, but it's hard to find answers to things like this.
I have a program with a bunch of modules/subs that each calculate a different variable. They're pretty complex, so I like to keep them separate. Now I want an earlier module to skip to another module based on user input. I thought I could use the call (sub name) method for this, but then the program returns to where the call line was and continues on that module from where it left off.
Example:
Module 1:
Sub NewPracticeSub()
Call otherpracticesub
MsgBox ("We've gone back to this sub... :(")
End Sub
Module 2:
Sub otherpracticesub()
MsgBox ("We're in the other practice sub!")
End Sub
I don't want it to return to Module 1. What can I do to have it switch control to Module 2 without it then returning to complete Module 1 upon completion of Module 2?
I feel like I just used the most confusing language possible to explain all of this, but thank you for your help anyways!!
Edit: I know I used the words module and sub interchangeably, and I know they're different. I like to keep each sub (which are each very large in my program) in their own modules because it's easier to keep track of them, and easier to explain/demonstrate the application flow to other people.
I think all you're looking for is the command Exit Sub which will make the program leave the subroutine without continuing any further, But the way you usually want to do this is, rather than calling a Sub, rather call a Function that returns a boolean value.
So, for example:
Public Function MyFunc() as Boolean
....
If [good] MyFunc = True
Else MyFunc = False
End Function
Then you could do something along the lines of:
Sub MyCallingSub()
...
If MyFunc = True then Exit Sub
Else ...
End Sub
It just adds in A LOT more felxibility and ability to choose whether you want to continue further in your sub or not.
Hope that makes sense.
Other than using the ugly End statement which I will describe below (and strongly recommend you to avoid), I'm not aware of any way to circumvent the call stack. Even John's response necessarily returns to the calling procedure, and evaluates another statement to determine whether to proceed or end.
This may yield undesirable outcomes, which is why I hesitate to recommend it, in favor of properly structuring your code, loops, etc., with respect to the call stack.
In any case, here is how you can use the End statement within your child subroutines, without needing any sort of public/global variables. This still allows you the flexibility to decide when & where to invoke the End statement, so it need not always be invoked.
Sub NewPracticeSub()
Call otherpracticesub, True
MsgBox ("We've gone back to this sub... :(")
End Sub
Sub otherpracticesub(Optional endAll as Boolean=False)
MsgBox ("We're in the other practice sub!")
If endAll then End '## Only invoke End when True is passed to this subroutine
End Sub
Why I say this method should be avoided, via MSDN:
"Note The End statement stops code execution abruptly, without
invoking the Unload, QueryUnload, or Terminate event, or any other
Visual Basic code. Code you have placed in the Unload, QueryUnload,
and Terminate events of forms and class modules is not executed.
Objects created from class modules are destroyed, files opened using
the Open statement are closed, and memory used by your program is
freed. Object references held by other programs are invalidated.
The End statement provides a way to force your program to halt. For
normal termination of a Visual Basic program, you should unload all
forms. Your program closes as soon as there are no other programs
holding references to objects created from your public class modules
and no code executing."
It will always return but that doesn't mean its a problem. I suggest you use Exit Sub as follows:
Sub NewPracticeSub()
Call otherpracticesub
**Exit Sub**
'Nothing more can execute here so its no longer a worry
End Sub
Module 2:
Sub otherpracticesub()
MsgBox ("We're in the other practice sub!")
End Sub
I would just like the program to end itself.
Application.Exit just keeps rolling me back in a loop.
EDITED to Include Code::
Module Module 1
Sub Main()
Sub1()
Sub2()
End Sub
Sub1()
EndSub
Sub2()
End Sub
End Module
EDIT: It seems to be looping back here to Sub ChooseDomain2.. I am including Sub 1 as well.
Sub ChooseDomain1()
Dim DomainName As Object
'Get List of all users on Domain using WinNT
DomainName = InputBox(messageOK, Title, defaultValue)
de.Path = "WinNT://****".Replace("****", DomainName)
If DomainName Is "" Then ChooseDomain2() Else StoreUserData1()
End Sub
Sub ChooseDomain2()
MsgBox("Welcome to the Domain Searcher. Click OK to Auto Search for Domain")
Dim MsgBoxResult As Object = ActiveDirectory.Domain.GetCurrentDomain.Name
MsgBoxResult = InputBox(messageCan, Title, MsgBoxResult)
de.Path = "WinNT://*****".Replace("*****", MsgBoxResult)
StoreUserData1()
End Sub
When it hits end Module it Just starts back from Square one.
Modules don’t execute at all – so it never “hits end module” and never starts “from square one”. Modules merely group methods that can be executed, and Main is a special method that serves as the start of your application.
That said, your code is guaranteed (!) not to execute repeatedly. Also, there is no Application.Exit anywhere in your code so it’s hard to see what you are actually executing. Not the code you showed, anyway.
Note that VB potentially executes code that you didn’t write (code can be auto-generated by the compiler, in particular the application framework) but this doesn’t seem to be happening in your case, and shouldn’t loop in any case. But again, this is impossible to say from the information you have given.
Application.Exit is not required as the console app will quit after it finishes executing the last line in Sub Main. As previously mentioned it is likely you have Sub1 calling Sub2 (or something similar), so set a breakpoint on the start of each sub to find which one is continually being called. Then you can do a search in your code to find where this sub is being called from.