Turning off a worksheet change-based event macro in Excel - vba

I've been stuck on this for awhile. I have a macro that runs every time a change is made and creates a data table that updates after each change with information like : Old Value, New Value, Data Changes, etc.
I am trying to kind of pause the worksheet change macro when I don't want it to be run anymore. Ex: If I am plugging in blank information, I don't need to document the fact that it used to be blank, and now it has data, etc.
I made some specifications for if I deleted an entire row as shown here:
If Target.Address = Target.EntireRow.Address Then Exit Sub
but that only dealt with one case. I just now thought of a very simple solution that I will post as the answer, so I hope this will help other people as much as it helped me

It's actually a very simple solution.
To begin pick a cell that has no information in but can be clearly located. For the purpose of this lets say A1.
Now pick key words that you will use to turn the macro on and off. Ex: I just chose True and False (capitals need to be consistent so pick what you want)
At this point, go to the beginning of your worksheet change macro and type in this right after the sub starts:
Private Sub Worksheet_Change(ByVal Target As Range)
If Range("A1").Value = "False" Then
Exit Sub
End If
Now, before your macro starts, it will always verify that the cell doesn't contain False, so if you want it on, put anything else but False, and if you want it off, keep the cell as False. Hope this helps someone.

You want to disable events while ensuring that you enable them later. To do this, use an error handler to catch all errors and set the state back at the end.
Public Sub example()
On Error GoTo errHandler
Application.EnableEvents = False ' => disable events
'The code ...
errHandler:
Application.EnableEvents = True ' => enable events
End Sub

Related

Flaw on VBA Variable Execution

Good Afternoon StackOverflow gang,
I'm currently in the process of fully automating my VBA script, however I've hit a slight bump. The following portion of my script take the date in a specific cell, and translates it farther down the script. The purpose of this portion of the script is to fully run the other macros below when it detects a change that has been made to the cell. It works on first run, but deletes the date located in A1 the second time I make a change to it. Any thoughts as to why this is occurring, or has anyone found structural errors when looking at this?
Private Sub Worksheet_Change(ByVal Target As Range)
If Intersect(Target, Me.Range("A1")) Is Nothing Then Exit Sub
Application.EnableEvents = False 'to prevent endless loop
Call Execute
MsgBox "The Date Has Changed!"
Application.EnableEvents = True
End Sub

VB, excel macro pause and resume working if possible

I cannot figure out the best way to do the following problem. Basically my macro (excel, VB) is checking several (100+) worksheets for correct values, if wrong value is found, I want it to stop, give me a warning, then I could have a look into the reason why the value is wrong, correct it manually and then I want to resume the macro, or remember the last value checked so if I return, it remembers where to continue (resume).
My current problem is that it finds the wrong value, then I can either make it stop so I check the problem, or it goes through all the sheets and then I have to remember which sheets had the wrong value.
What I thought of is make a list where the name of sheet is added every time a wrong value is found. The problem is that usually there is more than 1 wrong value in the same sheet if there is a wrong value at all and this added the same sheet name several times to the list. Another problem with that is that I cannot correct the values straight away.
I'm very inexperienced with programming and so would appreciate your idea on how to best approach this problem (I don't want to spend a long time on coding something which wouldn't be efficient for such a "simple" problem).
When the error is found (I'm assuming you've already been able to identify this), you can use the Application.InputBox function to prompt you for a new value.
For example, if rng is a Range variable that represents the cell being checked, and you have some logic to determine where the error happens, then you can just do:
rng.Value = Application.InputBox("Please update the value in " & rng.Address, "Error!", rng.Value)
The inputbox function effectively halts execution of the procedure, while waiting for input from the user.
If InputBox isn't robust enough, then you can create a custom UserForm to do the same sort of thing. But for modifying single range values, one at a time, the InputBox is probably the easiest to implement.
I believe you can handle this task by using one or two static local variables in your macro. A variable declared with "static" rather than "dim" will remember its value from the last time that procedure was run. This can hold where you left off so you can resume from there.
One thing that could be a problem with this solution would be if the macro gets recompiled. That would probably cause VBA to clear the value that the static variable was holding. Just doing a data edit in Excel should not cause a recompile, but you will want to watch for this case, just to make sure it doesn't come up. It almost certainly will if you edit any code between executions.
Create a public variable that stores the cell address of the last checked cell and use a conditional statement to see if it's "mid-macro" for want of a better phrase. here is a very crude example...
Public lastCellChecked As String
Sub Check_Someting()
Dim cell As Excel.Range
Dim WS As Excel.Worksheet
If Not lastCellChecked = vbNullString Then Set cell = Evaluate(lastCellChecked)
'// Rest of code...
'// Some loop here I'm assuming...
lastCellChecked = "'" & WS.Name & "'!" & cell.Address
If cell.Value > 10 Then Exit Sub '// Lets assume this is classed as an error
'// Rest of loop here...
lastCellChecked = vbNullString
End Sub
The best way to do this is to create a userform and as mentioned by prior users create a public variable. When the program finds an error store the cell and initiate the userform. Your code will stop on the userform. When you're done checking the problem have a button on the userform that you can click to continue checking. Your loop can be something like the below.
public y as integer
sub temp1 ()
rw1= range("a500000").end(xlup).row 'any method to create a range will do
if y = null then y=1
for x = y to rw1
cells(x,1).select
'check for the problem your looking for
if errorX=true then
userform1.show
y = activecell.row
exit sub
end if
next x
end sub
What about inserting a button (on the sheet or in a menubar) for stopping?
Insert the code below:
'This at the top of the module
Public mStop As Boolean
'This in the module
Sub MyBreak()
mStop = True
End Sub
'This is your macro
Sub YourMacro()
'This at the top of your code
mStop = False
'Your code
'...
'This code where you want to break
DoEvents '<<<< This makes possible the stop
If mStop Then
mCont = MsgBox("Do you want to continue?", vbYesNo)
If mCont = vbNo Then
Exit Sub
Else
mStop = False
End If
End If
'Your code
'...
End Sub
Now you need to create a button and link it to the macro called "MyBreak".

Default values for fields in a new row of a data table

When you have a data table in Excel, part of the standard functionality is that pressing tab in the last cell adds a new row at the bottom of the table. I want to auto-populate that new row with useful default values. In particular I want to put current date-time in one cell, and copy values into some other cells from the previous row of the table.
It is not workable to do that using formulae -- e.g. using =now() for the date-time stamp is inadequate because it will be auto-updated every time the spreadsheet recalculates, whereas I want it to retain the date-time at the moment when the row was added.
So I am trying to write VBA to be triggered by the event of the row being added, and in that code to write values into the cells of the new row. From MS documentation I thought DataTable.TableNewRow would be the appropriate event. But when I try to write any code for that event it is not being executed. When I look up DataTable in the VBA object browser the TableNewRow event is not listed.
Versions:
VBA for Applications 7.1
Excel 2013
So my questions:
Is the direction of my thinking right, or can you suggest a better approach?
Can you offer any working code that does something like this?
Is DataTable.TableNewRow the event I should be working with?
What do I need to do to get that event accessible in my VBA code?
You can try this:
Write this code in Thisworkbook.
Private Sub Workbook_Open()
Set ref_tbl = Sheet1.ListObjects(1).DataBodyRange
End Sub
Then below code in a Worsksheet Object.
Private Sub Worksheet_SelectionChange(ByVal Target As Range)
On Error GoTo halt
Application.EnableEvents = False
Dim tbl_rng As Range
Set tbl_rng = Me.ListObjects(1).DataBodyRange
If Not Intersect(Target, tbl_rng) Is Nothing Then
If tbl_rng.Rows.Count > ref_tbl.Rows.Count Then
MsgBox "Table increase in size"
'~~> Do your stuff here
Set ref_tbl = tbl_rng
End If
End If
forward:
Application.EnableEvents = True
Exit Sub
halt:
MsgBox Err.Number & ": " & Err.Description
Resume forward
End Sub
You will also need a Module to declare the public variable
Public ref_tbl As Range
So basically, this will tell you when your table increase in size.
If we're able to capture that, then you can do your stuff when that condition is met.
This works in the situation you describe in your question.
It will not work though when you insert row between entries in the table. Anyways, HTH.

'28' Out of Stack Space. Worksheet_Change and Application.ScreenUpdating

thanks in advance for any clarity you can offer.
In an Excel Workbook with many modules and worksheets, at the bottom of the VBA code for SHEET2, there is this Subroutine:
Private Sub Worksheet_Change(ByVal Target As Range)
Dim TargetCells As Range
Set TargetCells = Range("B1000:B1029")
If Not Application.Intersect(TargetCells, Range(Target.Address)) Is Nothing Then
Call SpecificSubRoutine
End If
End Sub
My understanding of this code is that it watches the entire sheet for ANY changes. If ANYTHING is changed, anywhere on the sheet, it runs the If statement. The If statement fails in the event that any of the changes made to the sheet take place outside of the specified TargetCells range, but this Sub still tries to validate the If statement EVERY time ANYTHING is changed on the sheet.
Now, you might be able to guess that my problem is some stack overflow. (Run-time error '28': Out of Stack Space)
Whenever the Worksheet_Change Sub runs, if the changes to the sheet were made inside of the TargetCells range, it calls SpecificSubRoutine which populates cells, which triggers the Worksheet_Change Sub for every time SpecificSubRoutine populates ANY cell. (SpecificSubRoutine also calls different modules, which of course populate cells, which of course trigger the Worksheet_Change Sub)
Not so good.
Also, most of the subroutines throughout the application are wrapped in Application.ScreenUpdating = False / Application.ScreenUpdating = True, which I mistakenly thought would limit the number of times Worksheet_Change is called to once, immediately after Application.ScreenUpdating = True runs.
NOTE OF IMPORTANCE: Neither SpecificSubRoutine nor any of the Subroutines called by it populate cells in the TargetCells range. I'm not quite that dim...
Here are my questions:
Is there a way to narrow the scope of what triggers the Worksheet_Change Sub, so that only changes in the TargetCells range triggers it? (instead of changes anywhere in the sheet)
Is there a way to do what I mistakenly thought that Application.ScreenUpdating would do? (make changes to the sheet all in one bulk update, as opposed to triggering a change with nearly every step)
Also, as an extra curiosity, is there a way to have Worksheet_Change watch 2 specific ranges (instead of the whole sheet?) Knowing how to do this would be paramount, and would likely solve all of the problems on this sheet.
My intuition is to add an End to the last part of SpecificSubRoutine, or to the end of any/all of the Subroutines called by it, but I'm just not sure this will circumvent the looping through Worksheet_Change multiple times, since Application.ScreenUpdating doesn't bulk update like I thought.
Ideas?
Part 1: No - the event handler responds to all changes on the sheet: any filtering in how you respond to that change must occur in the handler itself.
Part 2: answered by #simoco
Part 3 (and incorporating simoco's suggestion):
Private Sub Worksheet_Change(ByVal Target As Range)
Application.EnableEvents=False
If Not Application.Intersect(Me.Range("B1000:B1029"), Target) Is Nothing Then
Call SpecificSubRoutine
End If
If Not Application.Intersect(Me.Range("D1000:D1029"), Target) Is Nothing Then
Call SomeOtherSpecificSubRoutine
End If
Application.EnableEvents=True
End Sub

Making excel graphs appear/disappear

I want a graph only to appear when a condition is fulfilled. To be more precise: I have a drop down menu that changes the content of a graph. If the menu point "Total revenue" is clicked, I want a second graph to appear. I am new to VBA and this is what I came up with so far:
Sub Iffuntion()
Dim SelectedChart As Range
Dim notVisible As Boolean
If Range("D100").Value = Range("E100").Value Then
ActiveSheet.ChartObjects("Testchart").Visible = True
Else
ActiveSheet.ChartObjects("Testchart").Visible = notVisible
End If
End Sub
It works, but I have to execute the VBA to make the graph appear/disappear and I would like that to happen automatically. Also the condition should eventually be in another worksheet to keep the sheet with the graphs nice and tidy. I read that to achieve this I have toI have to activate the other worksheet. Would you recommend this way or is there a better solution?
Thanks for the help and best regards!
Pete
EDIT: Here is the link to a sample file with the proposed solution of Cor_Blimey, that I couldn't get to work properly. The interconnections in the excel are more complicated than they would have to be, but I wanted to be as accurate ad possible in displaying what is actually happening in my excel. Thanks for taking a look!
https://dl.dropboxusercontent.com/u/18406645/sample.xlsm
Assuming you mean that they change, from a data validation drop down list, the contents of a cell then you can put your code into the Worksheet's Worksheet_Change event. This event is fired when the user changes the content of a cell (or by an external link).
Then test for the cell being the right cell then run your code.
Like:
Private Sub Worksheet_Change(ByVal Target As Range)
Dim rng As Range
Set rng = Intersect(Target, Me.Range("D100"))
If Not rng Is Nothing Then
If rng.Value = Me.Range("E100").Value Then
Me.ChartObjects("Testchart").Visible = True
Else
Me.ChartObjects("Testchart").Visible = False
End If
End If
End Sub