I have a large chunk of code that manually defines each element of an array for me that is annoyingly long and positioned at the beginning of one of my functions. I would like to hide the code or set it somewhere else WITHOUT changing its current meaning in any way if possible. I would like to avoid making the array global. It's also not reasonable to pass the array from all the places that the function is called.
Is there some way to simply have the code sit somewhere else while VBA sees it as being a part of the function, i.e. as if I had all the elements defined at the beginning of the function? I imagine having some sort of "Sub" that's not actually a Sub (I might call it an "Excerpt") of code with the elements populated there with a single line in the function that calls the "Excerpt" by name.
You can return an array from a function so it could be in a module on its own;
public Function getArr() as string()
Dim arr(10) as string
...
arr(5) = "Cakey"
getArr = arr
End Function
Called with
Dim arry() as string: arry = getArr()
msgbox arry(5)
Related
I have a large number of functions that I need to call which each have the same arguments and I'd like to be able to centralize them to avoid unwieldy blocks of code. Obviously I could use a wrapper function to just call all the others, but I don't always call all of them. My next thought is that I could place the functions in a list or dictionary and call them from there, much like in Python:
def foo():
return "foo"
myDict = { "foo": foo }
myDict["foo"]()
Returns foo
Is something similar possible in VBA? If so, what is the simplest way of doing it?
If the functions are inside objects/Classes then you can call them by name directly.
The below code works inside SHEET1 because it's an object.
It will not work in a MODULE as that is outside the capabilities of CALLBYNAME function.
So you can store the Names in the Key of the dictionary and then just use the key (no function pointer is needed)
Public Sub Something(arg1 As String)
MsgBox arg1
End Sub
Public Sub test()
CallByName Sheet1, "Something", VbMethod, "data 1"
End Sub
There does not appear to be a really straight forward way of doing this, however, it can be done using a combo of a list and the CallByName function.
You can make a list which contains all the function names as strings:
myFunctions = ( "foo" "bar" "baz" )
You can then iterate over the array to call the functions:
For Each functionName in myFunctions
CallByName Sheet1, functionName, VbMethod, listOfArguments
Next functionName
Functions can be filtered out with If statements
I have dificulties figuring how a function can return an object in Excel VBA.
For example, in Java, I am used to write it like this:
Private ArrayList<> getARandomArrayList() {
//... My code
return anArrayList;
}
This method should return an arrayList that I can use.
If I do this in Excel, I believe it is supposed to look like this:
Function getARandomArrayList() As System.Collections.ArrayList
'... My code
getARandomArrayList = anArrayList
End Function
When I try to use this kind of function, I get a "Compile error: User-defined type not defined" error window. If I use variables type like Double or String, I have no problem. It is only with objects that I get errors.
A VBA.Collection may work for you, depending on your needs. (Edit: And as Vincent points out in the comments, no additional references are required.) Here's what it'd look like to use one:
Function getSomeCollection() As VBA.Collection
'Declare a collection
Dim newCollection As VBA.Collection
'Initialize the collection
Set newCollection = New VBA.Collection
'Add a string.
'Other methods are Item (access by index), Count, and Remove (by index)
newCollection.Add "hello"
'Reference the collection (note it's 1-based)
MsgBox newCollection(1)
'Set the return value
Set getSomeCollection = newCollection
End Function
As Rory said:
You have to set a reference to the relevant object library in order to be able to declare a variable as a type contained in it
I went in reference and activated System librairies.
I have a an array in my module, so I want to display the contents of my array in a form textbox, here is my array
Module Module1
Sub AddCourse()
Dim Subjects() = {"Ms Office 2007", "internet and commmunications", "Lifetime skills"}
For i = 0 To UBound(Subjects) ' FOR LOOP TO WRITE AN ARRAY
i = i +1
Subjects(i)
Next
txtComputer.Text = subjects()
my problem is, when I try to use my texbox txtComputer in my module I get an error.
My question is, how do I make a form textbox to be used in a module
I get an error that reads "Error'txtComputer' is not declared. It may be inaccessible due to its protection level."
My question is based on, how do I get this error fixed?
There are several suggestions I have for you.
First, don't use UBound. That's an old VB6 function that is only provided for backwards compatability. You should instead use Subjects.Length.
Next, when you're incrementing the i variable, you don't need to say i = i + 1. You can just use the += operator for that (e.g. i += 1).
However, you shouldn't be explicitly incrementing i inside your For loop, anyway. The loop automatically increments the variable for you each time it iterates through the loop. If you do it explicitly yourself inside the loop, like that, it will skip every other item.
Next, in this case, you really should just use a For Each loop, rather than an iterator:
For Each subject As String in Subjects
'...
Next
Next, you aren't actually concatenating the items together inside you loop. You should be doing something like this:
For Each subject As String in Subjects
txtComputer.Text += subject
Next
However, in that case, for efficiency sake, you really ought to use a StringBuilder, like this:
Dim builder As New StringBuilder()
For Each subject As String in Subjects
builder.Append(subject)
Next
txtComputer.Text = builder.ToString()
But, all of this is moot because all you really need to do is to call String.Join:
txtComputer.Text = String.Join(", ", Subject)
As far as why you can't access the text box from the module, that is because the module is a separate object, so the text box is entirely out of scope. For instance, what if you had two instances of your form displayed at the same time? How in the world would this module know which form's text box you were referring to? The simplest way to correct that would be to pass a reference to your form into the module's method, like this:
Module Module1
Sub AddCourse(f As MyFormName)
f.txtComputer.Text = "Hello world"
End Sub
End Module
And then you could call it from the form, like this:
AddCourse(Me)
However, that would be exceptionally bad practice. Ideally, nothing outside of the form's code should ever deal directly with any of the controls on the form. So, the far better way to do it would be to simply have the method return the data, and then have the form set it's own control to the data that is returned, for instance:
Module Module1
Function GetCourse() As String
Return "Hello world"
End Function
End Module
And then call it from the form like this:
txtComputer.Text = GetCourse()
You can use String.Join to create a string which separates each subject with Environment.NewLine:
txtComputer.Text = String.Join(Environment.NewLine, Subjects)
The problem with your for loop is that it makes no sense at all since you have already declared and initialized the array in one line.
If you want to use a loop anyway, you can use a StringBuilder to concat all strings together:
Dim subjectBuilder = New System.Text.StringBuilder
For Each subject In Subjects
subjectBuilder.Append(subject).Append(Environment.NewLine)
Next
If subjectBuilder.Length <> 0 Then subjectBuilder.Length -= Environment.NewLine.Length
txtComputer.Text = subjectBuilder.ToString()
I have been looking through old code to get familiar with the system I use and found a piece of code that I feel can be used better.
What goes on here is some data gets added to the collection(around 150 string variables, some with two variables(variableName/VariableValue), most with only one(VariableName)). It will try to set a module level string variable to the item of the collection passing it the index(variableName) then if there's a value setting the VariableVAlue to the module level variable.
What I feel needs work is that if the collection is passed a variable and the variable doesn't have a value it will return a "" which would cause a runtime error hence there's a On Error GoTo Handler code to manually add a "" to the collection. I feel there's a better way to do this rather than knowing there will be a runtime issue then solving it after catching it. Would there be a way to have a return "" not throw an exception or would the use of an Array also work here since it's a "collection" as well?
Here's an example to try to help visualize:
Public Function GetCollectionVariable(ByVal varName as string) as String
If collection1 Is Nothing Then
m_collection1 = New Collection
End If
On Error GoTo Handler
GetCollectionVariable = collection1.Item(VarName)
exit function
Handler:
collection1.add("", VarName)
GetCollectionVariable = ""
End FUnction
Thanks for your time!!
If Collection1 is a dictionary, you can use TryGetValue.
In my previous question, How do I assign a value to a property where the property name is supplied at runtime in VBA?, I learned to use CallByName to set a property in a class at run time.
This time, however, I'm trying to figure out how to get an object at run time from a string.
For example, let's say I have a string with the following data: Worksheets("RAW DATA").Range("A1").QueryTable.
Here's what I might try to do where the data above is the input for strParam below:
Function GetObject(strParam As String) As Object
GetObject = SomeFunction(strParam)
End Function
In this case, GetObject should return a QueryTable when evaluated against Worksheets("RAW DATA").Range("A1").QueryTable. Is there anything in VBA that could take the place of SomeFunction from the example above?
Active Scripting Engine can help you. Instantiate ScriptControl ActiveX, use .AddObject() method to add reference to Excel's Application object to the script control's execution environment, set the third parameter to True to make all Application's members accessible too. Then just use .Eval() method to evaluate any property or method, which is the Application's member. The example below shows evaluation of Worksheets() property:
Sub TestQueryTable()
Dim objQueryTable As QueryTable
Dim strEvalContent As String
strEvalContent = "Worksheets(""RAW DATA"").Range(""A1"").QueryTable"
Set objQueryTable = EvalObject(strEvalContent)
objQueryTable.Refresh
MsgBox objQueryTable.Connection
End Sub
Function EvalObject(strEvalContent As String) As Object
With CreateObject("ScriptControl")
.Language = "VBScript"
.AddObject "app", Application, True
Set EvalObject = .Eval(strEvalContent)
End With
End Function
If you are on 64-bit Office, this answer may help you to get ScriptControl to work.
This time you're out of luck. There is no VBA equivalent of eval (not in Excel anyway...there is in Access VBA).
(Application.Evaluate() evaluates strings as Excel expressions, not as VBA code.)
There's the "Evaluate" method (or [ ] brackets). I don't think it will do exactly what you expect - as in run VBA code found in a string. You can look it up in the VBA help menu.