I am programmatically adding several controls to a form in my project, then when a timer ticks, I want to remove all of the existing controls and replace them with new controls and new, updated data (as an aside - is this horrible coding?)
I had a look on msdn and found the controlcollection.clear() method which sounds like it will do what I want. However I get a rather cryptic "Reference to a non-shared member requires an object reference" error whenever I try to use the method.
Why does this happen? I am a newbie and I'm not sure what the non-shared member is (or what those are) or how to give it an object reference.
This is not the code I am using, but I think it illustrates the point most simply:
Private Sub add_and_remove()
For i = 0 To 10
Dim t As New TextBox
t.Text = "whatever"
Me.Controls.Add(t)
Next
Me.ControlCollection.Clear()
End Sub
Thanks in advance!
From comments: Use
Me.Controls.Clear() as opposed to Me.ControlCollection.Clear()
Or better still, don't clear the controls at all and just update the properties of the controls.
Thanks all!
Related
System Description: I have a userform that takes input on an item that is being returned. A user clicks the row of the item that needs to be returned and then clicks a "Check-In button"
My Attempt: I created a button checkin_cmdbutton on the spreadsheet that measures which item is selected by which cell is selected Application.ActiveCell.Row, writes the info into a userform Checkin_Form, the user finishes the rest of the check-in info, and clicks submit.
This code is the event for the button checkin_cmdbutton on the spreadsheet:
Private Sub checkin_cmdbutton_Click()
Set ItemID = Cells(Application.ActiveCell.Row, 1)
Set ItemDescription = Cells(Application.ActiveCell.Row, 2)
If ItemID Is Nothing Then
MsgBox ("ID is null, ending...")
Exit Sub
End If
Checkin_Form.UserForm_Initialize
Checkin_Form.itemid_dynamiclabel.Caption = ItemID.Value
Checkin_Form.description_dynamiclabel.Caption = ItemDescription.Value
Checkin_Form.checkin_datepicker.Value = Date
Checkin_Form.Show
End Sub
Problem: The code throws an error 91 "Object variable or with block variable not set" at Checkin_Form.itemid_dynamiclabel.caption and the following 2 lines. Why is an object on a form throwing this error? I can't declare these, can I?
You shouldn't be explicitly calling UserForm_Initialize - that's an event handler, and there's a reason handlers are Private by default: they're invoked by the event provider, when the event provider deems it necessary - in this case, when the object instance is getting initialized.
The best way to ensure the form gets initialized properly, is to treat it like the object it is, instead of storing global state on its default instance.
A UserForm class is little more than a class module with a designer and a VB_PredeclaredId module attribute. This attribute makes VBA create a global-scope object variable named after the class, and that is how this code is legal:
UserForm1.Show
Except, it shouldn't be.
You DON'T want to store global state in the default instance: that's the very last thing you want, especially if your form involves dynamic controls.
New it up instead.
With New UserForm1
.Show
'what follows only executes when the form is closed:
'...
End With
For this to work, you must handle the form's QueryClose event, to prevent the object instance from self-destructing itself when the user clicks the [X] button.
For this to work, you must also avoid destroying the form yourself, e.g. with Unload Me (or worse, Unload UserForm1) calls - say, when the user clicks the [Ok] button. Instead, you Hide (or Me.Hide) the form, so that the caller (the code that New'd it up) can still access the object's state.
From the look of your code - i.e. with the .Show call being the very last thing your macro does, I can tell that you're having the form run the show: this is an anti-pattern that will keep creating problems every time you do that.
Forms don't implement application logic: forms present and collect data. Nothing more, nothing less. It's not the form's job to write to any spreadsheet, or even to know anything about worksheets.
Read this recent article of mine if you want more information about doing forms right.
Now, the actual problem.
Checkin_Form.itemid_dynamiclabel.Caption = ItemID.Value
If that label is dynamic (i.e. created at run-time), then I'm surprised accessing it like this even compiles. First, remove the underscore in the form's name: underscores have a special meaning in VBA - I'm sure you've noticed the pattern by now, of how VBA generates event handlers for a given object:
Private Sub ObjectName_EventName()
End Sub
If ObjectName or EventName has an underscore, you're asking for compile errors at one point or another - one day you'll want to use an Implements statement and discover that your code can't be compiled anymore, if you kept that underscore habit: better lose it now.
If the control is dynamic, you can't do what you're trying to do the way you're doing it.
Dynamic controls need to be accessed through the form's Controls collection:
Dim myLabel As MSForms.Label
Set myLabel = Me.Controls("NameOfTheLabelControl")
Otherwise, you need to keep a reference to the dynamic contols at module-level, in the form's code-behind - you could expose it via a property:
Option Explicit
Dim myLabel As MSForms.Label
Private Sub UserForm_Initialize()
Set myLabel = Me.Controls.Add(...)
End Sub
Public Property Get ThatLabel() As MSForms.Label
Set ThatLabel = myLabel
End Property
Or better, use an actual model class, and let the calling code not be bothered with controls at all - see the previously linked article for details.
TL;DR:
You're getting that error because your label object instance isn't initialized, i.e. it's Nothing. Since you aren't showing your form's code-behind, we can't really point out why that is the case, but my money is on the form's default instance making you yet another victim of the "hey look how easy it is!" VBA tutorials that teach things wrong.
Implement the worksheet-handling code outside the form, make the form collect data, make the calling code read this data after the form is hidden, and then make the calling code create and destroy the form instance.
Now, with all that said, I've no idea why you think you need a dynamic control for this.
Just shooting in the dark, as far as I really do not know the names of your variables and what they are (a few screenshots will be helpful). Try like this, if your code is in a form (as far as you have _Click I assume it is):
Private Sub checkin_cmdbutton_Click()
Set ItemID = Cells(Application.ActiveCell.Row, 1)
Set ItemDescription = Cells(Application.ActiveCell.Row, 2)
Me.itemid_dynamiclabel.Caption = ItemID.Value
Me.description_dynamiclabel.Caption = ItemDescription.Value
Me.checkin_datepicker.Value = Date
Me.Show
End Sub
And try at least declaring the variables (e.g. ItemID etc) and using Option Explicit on top.
I have a quick question. How can i check an item's properties within an event procedure? Here is a snippet of what I'm trying to do:
Private Sub application_ItemLoad(ByVal Item As Object)
Dim myolitem As Object
Set myolitem = Item
If myolitem.Class = olMail Then
If myolitem.UnRead Then
UserForm2.Show vbModal
End If
End If
End Sub
Thank you in advance for your help.
You code looks good, I don't see anything strange there.
Hope you will find the Getting Started with VBA in Outlook 2010 article helpful.
Some events (e.g. AfterWrite, ItemLoad) only allow a limited number of properties to be accessed. In your particular case, these are Class and MessageClass - see ApplicationEvents_11_Event.ItemLoad event.
I don't know if MAPIOBJECT is accessible in ItemLoad (I know for sure it is accessible in the AfterWrite event), you can (in theory) access the properties using Extended MAPI (C++ or Delphi) or Redemption (I am its author).
I'd like to run a user form with status bar.
I show my form with code bolow.
How should I declare variables and assigning new values to those variables?
Very important: I have to use late binding in my project.
Sub RunMyUserForm()
With MyUserForm
.LabelProgress.Width = 0
.TextBox1 = 1
'to make the progress bar color match the workbook's current theme:
.LabelProgress.BackColor = ActiveWorkbook.Theme.ThemeColorScheme.Colors(msoThemeAccent1)
.Show vbModeless
End With
End Sub
Thank you in advance for your help!
Updated information:
When I try to run my macro with "Option Explicit", it doesn't work (Compile error: Variable not defined - part of code msoThemeAccent1 is marked as yellow color). That's why I asked for help in defining the variables.
When I try to run my macro without "Option Explicit", it dosen't work (Err.Description: "Value is out of range", Err.Number: -2147024809)
When I try to run my macro with early binding (reference to "MS Office Object Library" via Tools/References in VBE) everything works perfect with (and without) "Option Explicit".
Your compiler is seeing msoThemeAccent1 as a variable, and it is undeclared. This is why your code won't run with Option Explicit and also why your code raises an error when you disable Option Explicit. .Colors is a 1-based collection (?) so when you call:
ActiveWorkbook.Theme.ThemeColorScheme.Colors(msoThemeAccent1)
It is compiling to:
ActiveWorkbook.Theme.ThemeColorScheme.Colors(0)
Which raises an expected, albeit cryptic error.
I used some code to check the value of this constant, but in hindsight I should have just referred to the documentation:
http://office.microsoft.com/en-us/excel-help/HV080559557.aspx
This should fix it for you
ActiveWorkbook.Theme.ThemeColorScheme.Colors(5)
Alternatively, if you need to rely on this value in several places in your code, you could declare a variable (public or private, scope depends on what you need it for).
Public Const myAccentColor1 as Long = 5
And then, in your code you could:
ActiveWorkbook.Theme.ThemeColorScheme.Colors(myAccentColor1)
Revised
I understand now, without reference to MS Office Object Library this makes sense. This is one of the few libraries that I maintain a reference to in my XLSB file, so my confusion was a result of the fact that I thought I was using an appropriate late-binding, but I was really using early-binding.
This is probably a simple one but I can't seem to figure it out.
I have a bunch of form items created by the form designer declared as (in frmAquRun.Designer.vb)
Public WithEvents btnAquRunEvent1 As VisibiltyButtonLib.VisibilityButton
Public WithEvents btnAquRunEvent2 As VisibiltyButtonLib.VisibilityButton
... etc
And I basically want to be able to supply a number to a function access each of these fields. So I wrote this function. (in frmAquRun.vb)
Const EVENT_BUTTON_PREFIX As String = "btnAquRunEvent"
Public Function getEventButton(ByVal id As Integer) As Windows.Forms.Button
Dim returnButton As Windows.Forms.Button = Nothing
Try
returnButton = DirectCast(Me.GetType().InvokeMember(eventButtonName, Reflection.BindingFlags.GetField Or Reflection.BindingFlags.Public Or Reflection.BindingFlags.Instance, Nothing, Me, Nothing), Windows.Forms.Button)
Catch ex As Exception
End Try
Return returnButton
End Function
But it always seems to be generating field not found exceptions.
The message in the exception is "Field 'ATSIS_ControlProgram.frmAquRun.btnAquRunEvent1' not found.".
The namespace and form name in the message are correct. Any idea what i'm doing wrong?
The problem is that for WithEvents fields, VB actually creates a property that does the necessary event handler attaching and detaching. The generated property has the name of the field. The actual backing field gets renamed to _ + original name.1)
So in order for your code to work just prefix the button name by _ or use the BindingFlag that corresponds to the property getter (instead of GetField).
Alternatively, you can do this a lot easier by using the Controls collection of the form:
returnButton = DirectCast(Me.Controls(eventButtonName), Windows.Forms.Button)
But beware that this only works if the button is top-level, i.e. not nested within a container control on the form.
1) This is an implementation detail of the VB compiler but it’s portable (especially to Mono’s vbnc compiler) since the handling for WithEvents fields is described in great detail in the VB language specifications.
The problem is that the event handlers aren't really fields. As compiled they're really properties that implement add_btnAquRunEventX, remove_btnAquRunEventX and fire_btnAquRunEventX methods. There are ways of using reflection to get around this, but that's probably not the best way to approach the problem. Instead you can simply create a List<> and populate it with the event handlers, then index into that list.
I'm a little rusty in VB syntax but it should look something like this:
Dim events = New List<EventHandler>()
events.Add( btnAquRunEvent1 )
events.Add( btnAquRunEvent2 )
....
events( 0 )( null, EventArgs.Empty )
Take a step back though and evaluate why you're invoking by index. There may be a simpler way of abstracting the whole thing that doesn't involve all this indirection.
I am trying to program an Excel module where it dynamically inserts code in new objects in a form that is created at design time.
I am using this code where "Code" contains a string with the actual code that should go into the DstrFiles object.
Dim DstrFiles As Object
Set DstrFiles = ThisWorkbook.VBProject.VBComponents("DistributeFiles")
With DstrFiles.CodeModule
.InsertLines .CountOfLines + 1, Code
End With
My problem is that when I use the .InsertLines, McAfee removes the entire Code from my module, is there a way to work around this?
First I create the label with:
Form1.Controls.Add("Forms.Label.1", "Label1", True)
Then I use the .InsertLines to create some code to go with the Label.
For instance, I want the background color of the label to turn red when someone clicks on it. This has been very easy to accomplish with the ".InsertLines".
An ugly way to work around this is to just create a bunch of code beforehand that is ready in the background and then limit the amount of labels that may be created on the fly. - I hope it won't come to that.
I have been googeling around, and this seems to be a known problem with McAfee.
Do anyone know a way to create a dynamic user form that can add code to new labels or button that are added with the Contrls.Add method?
You should not be generating new labels by writing code that creates the controls.
You should be using the .Add method on the Controls collection to create new labels.
For example:
UserForm1.Controls.Add("Forms.Label.1", "foo", True)
You can use WithEvents to get the events.
For example, in UserForm1,
Public WithEvents a As MSForms.Label
Private Sub a_Click()
MsgBox "label clicked"
End Sub
Private Sub CommandButton1_Click()
Set a = UserForm1.Controls.Add("Forms.Label.1", "foo", True)
a.Visible = True
a.Caption = "Hi There"
End Sub
If you want to make a dynamic array of newly added controls, you'll need to create a little wrapper class. Sample code for that is here.
If possible I would recommend against dynamic generation of code (smells like a self-modifying program?).
It's maybe hard to say without knowing your specific problem but I bet there is a better solution using a function with the necessary parameters.
You might be able to workaround this version of McAfee. But the next version of the data-files, or another malware blocker might block you anyhow.
So you can create code like this to run on you development machine, but it will never (or only temporary) work when distributed to customers.