I'm trying to store an array value so that I can reuse when Sub is called more than once.
I would like to prevent from reassigning values to the array if value exist.
My code is something like this.
Dim views()
Sub runit()
For i=0 To 3
test()
Next
End Sub
Sub test()
ReDim Preserve views(0)= "test"
' - other codes that I want to run-
End Sub
I get " Type mismatch :'choseviews'" error.
If I move "Dim views()" inside "Sub test", I don't get the error.
How do I declare global array in VBScript?
If it's not possible, is there any ways to prevent reassigning array when Sub is called?
This following code does not work but you may get an idea what I'm trying to do .
Dim views()
Sub runit()
For i=0 To 3
test()
Next
End Sub
Function IsArrayDimmed(arr)
IsArrayDimmed = False
If IsArray(arr) Then
On Error Resume Next
Dim ub : ub = UBound(arr)
If (Err.Number = 0) And (ub >= 0) Then IsArrayDimmed = True
End If
End Function
Sub test()
If IsArrayDimmed(views) Then
Else
ReDim Preserve views(0)= "test"
End If
' - other codes that I want to run-
End Sub
Thank you for your help.
If I understand correctly, it seems like you want to declare a global array variable, and then add items to that array, without being limited to a static number of elements. In other words, you need to dynamically increase the size of the array by re-allocating it.
The global declaration is correct and belongs where you have it:
Dim views()
What you wrote here is incorrect syntax, you cannot assign a value and ReDim at the same time.:
ReDim Preserve views(0)= "test"
Additionally, that would ReDim the array to size 0, which is the opposite of what you want.
If you wish to "push" values on that array you should use a function like this which handles the redim to increase the size of the array before adding the value to the tail of the array:
Function Push(ByRef arrTarget, ByVal varValue)
Dim intCounter
Dim intElementCount
ReDim Preserve arrTarget(UBound(arrTarget) + 1)
If (isObject(varValue)) Then
Set arrTarget(UBound(arrTarget)) = varValue
Else
arrTarget(UBound(arrTarget)) = varValue
End If
Push = arrTarget
End Function
Use it like this:
Call Push(views,"test")
Any variable instantiated in the global scope will be a "global" variable. However, you should pass that variable explicitly into other scopes "by reference" if you want to have any changes persist in the original scope. You can do that using the ByRef keword in your Function or Sub declaration.
Sub test(ByRef viewsArray)
Now within test you will reference viewsArray which acts as a pointer to views.
Related
I want to check collection variable contains the key or not in visual basic 6.0
Below is the collection variable I am having
pcolFields As Collection
and I want to check whether it contains the field Event_Code. I am doing this as below but it not worked for me.
If IsMissing(pcolFields("Event_Code")) = False Then
'Do Something
End If
Here is an example solution with try-catch:
Private Function IsMissing(col As Collection, field As String)
On Error GoTo IsMissingError
Dim val As Variant
val = col(field)
IsMissing = False
Exit Function
IsMissingError:
IsMissing = True
End Function
Use it like this:
Private Sub Form_Load()
Dim x As New Collection
x.Add "val1", "key1"
Dim testkey As String
testkey = "key2"
If IsMissing(x, testkey) Then
Debug.Print "Key is Missing"
Else
Debug.Print "Val is " + x(testkey)
End If
Exit Sub
End Sub
You could also try a to Implement or Subclass the Collection and add a "has" Function
Collections are not useful if you need to check for existence, but they're useful for iteration. However, collections are sets of Variants and so are inherently slower than typed variables.
In nearly every case it's more useful (and more optimal) to use a typed array. If you need to have a keyed collection you should use the Dictionary object.
Some examples of general ways of using typed arrays:
Dim my_array() As Long ' Or whichever type you need
Dim my_array_size As Long
Dim index As Long
Dim position As Long
' Add new item (push)
ReDim Preserve my_array(my_array_size)
my_array(my_array_size) = 123456 ' something to add
my_array_size = my_array_size + 1
' Remove item (pop)
my_array_size = my_array_size - 1
If my_array_size > 0 Then
ReDim Preserve my_array(my_array_size - 1)
Else
Erase my_array
End If
' Remove item (any position)
position = 3 'item to remove
For index = position To my_array_size - 2
my_array(index) = my_array(index + 1)
Next
my_array_size = my_array_size - 1
ReDim Preserve my_array(my_array_size - 1)
' Insert item (any position)
ReDim Preserve my_array(my_array_size)
my_array_size = my_array_size + 1
For index = my_array_size - 1 To position + 1 Step -1
my_array(index) = my_array(index - 1)
Next
my_array(position) = 123456 ' something to insert
' Find item
For index = 0 To my_array_size - 1
If my_array(index) = 123456 Then
Exit For
End If
Next
If index < my_array_size Then
'found, position is in index
Else
'not found
End If
Whilst it may seem like a lot code. It is way faster. Intellisense will also work, which is a bonus. The only caveat is if you have very large data sets, then redim starts to get slow and you have to use slightly different techniques.
You can also use a Dictionary, be sure to include the Microsoft Scripting Runtime reference in your project:
Dim dict As New Dictionary
Dim value As Long
dict.Add "somekey", 123456
dict.Remove "somekey"
value = dict.Item("somekey")
If dict.Exists("somekey") Then
' found!
Else
' not found
End If
Dictionaries like collections just hold a bunch of Variants, so can hold objects etc.
We can check following code into vb.net code
If Collection.ContainsKey(KeyString) Then
'write code
End if
Collection is variable of Dictionary and KeyString is a key string which we need to find into collection
The method from efkah will fail if the Collection contains objects rather than primitive types. Here is a small adjustment:
'Test if a key is available in a collection
Public Function HasKey(coll As Collection, strKey As String) As Boolean
On Error GoTo IsMissingError
Dim val As Variant
' val = coll(strKey)
HasKey = IsObject(coll(strKey))
HasKey = True
On Error GoTo 0
Exit Function
IsMissingError:
HasKey = False
On Error GoTo 0
End Function
I'm trying to put together tests in HP Unified Functional Testing
the way a programmer would.
For those unaware, the tool uses VBScript as its driver.
Because I want to use data from the same DataTable across multiple UFT actions
-- and because the Global table already has a different set of data on it
-- I want to retrieve data from an external file.
UFT happily supports this function.
My current plan is that, depending on which test I'm running,
I will iterate through only a range of rows in that table.
This is the script I've come up with:
' targets the local sheet, but
' not the same value as dtLocalSheet
Const sheetNum = 2
dim sheetRowCount
DataTable.ImportSheet "PersonFile.xlsx", 1, sheetNum
sheetRowCount = DataTable.GetSheet(sheetNum).GetRowCount
dim firstRow, lastRow
firstRow = Parameter("FirstPersonIndex")
lastRow = Parameter("LastPersonIndex")
If sheetRowCount < lastRow Then
lastRow = sheetRowCount
End If
If sheetRowCount >= firstRow Then
Dim i
For i = firstRow To lastRow
DataTable.SetCurrentRow i
' begin payload
MsgBox(DataTable.Value("LastName", dtLocalSheet))
' end payload
Next
End if
I don't want to have to repeat all this boilerplate
every time I want to use this pattern.
I'd really like to have something like:
In a Function Library:
sub LoopThroughSheetAnd(sheetFile, doThis)
' targets the local sheet, but
' not the same value as dtLocalSheet
Const sheetNum = 2
dim sheetRowCount
DataTable.ImportSheet sheetFile, 1, sheetNum
sheetRowCount = DataTable.GetSheet(sheetNum).GetRowCount
dim firstRow, lastRow
firstRow = Parameter("FirstRow")
lastRow = Parameter("LastRow")
If sheetRowCount < lastRow Then
lastRow = sheetRowCount
End If
If sheetRowCount >= firstRow Then
Dim i
For i = firstRow To lastRow
DataTable.SetCurrentRow i
call doThis()
Next
End if
end sub
In the original action...
sub Payload1()
MsgBox(DataTable.Value("LastName", dtLocalSheet))
end sub
LoopThroughSheetAnd "PersonFile.xlsx", Payload1
In a separate action, 3 or 4 steps later...
sub Payload2()
' compare the data against another data source
end sub
LoopThroughSheetAnd "PersonFile.xlsx", Payload2
The above code doesn't work in VBScript.
A type mismatch error is thrown
as soon as we try to pass Payload1 as a parameter.
How could one reasonably pull this off in VBScript?
Bonus points if the answer also works in UFT.
You can pass functions as parameters with the GetRef() function. Here's a utility map function, like you'd find in JavaScript that accepts an array and calls a function for each element of the array:
Sub Map(a, f)
Dim i
For i = 0 To UBound(a)
' Call a function on each element and replace its value with the function return value
a(i) = f(a(i))
Next
End Sub
Map MyArray, GetRef("SomeFunc")
Now you could write SomeFunc so that it operates on a value and returns an updated value:
Function SomeFunc(i)
SomeFunc = i + 1
End Function
This works fine. map calls SomeFunc using the function "pointer" we passed to it.
You could do something similar with your LoopThroughStreetAnd function:
LoopThroughStreetAnd "PersonFile.xlsx", GetRef("Payload2")
The standard way of callbacks in VBScript uses GetRef, as in this demo.
When using objects, you can wrap a call to a method in an object, and then you can pass the object. (This is approximately what happens in other languages already, you just have to do it manually in VBScript.)
The only issue is that any method called this way has to be Public.
I would use a naming scheme of something like "Func1", "Func2", "Action1", "Action2", etc., depending on the arity of the functions and whether they return values or not.
Dim s : Set s = New Something : s.Run
Class Something
Public Sub HowToPassMe(pValue)
WScript.Echo pValue
End Sub
Public Sub Run
Dim action : Set action = New Action1Wrapper
Set action.Target = Me
Dim se : Set se = New SomethingElse
se.DoSomethingElse action
End Sub
End Class
Class SomethingElse
Public Sub DoSomethingElse(pAction1)
pAction1.Action1("something")
End Sub
End Class
Class Action1Wrapper
Private mTarget
Public Property Set Target(value) : Set mTarget = value : End Property
Public Sub Action1(p1)
mTarget.HowToPassMe(p1)
End Sub
End Class
Using Execute, Action1Wrapper can also be written something like the following. You can also write a factory class for easier use.
Class Action1Wrapper
Private mTarget
Public Property Set Target(value) : Set mTarget = value : End Property
Private mName
Public Property Let Name(value) : mName = value : End Property
Public Sub Action1(p1)
Execute "mTarget." & mName & "(p1)"
End Sub
End Class
Class Action1Factory_
Public Function Create(pTarget, pName)
Dim a1 : Set a1 = New Action1Wrapper
Set a1.Target = pTarget
a1.Name = pName
Set Create = a1
End Function
End Class
Dim Action1Factory : Set Action1Factory = New Action1Factory_
Used as:
Dim action : Set action = Action1Factory.Create(Me, "HowToPassMe")
Dim se : Set se = New SomethingElse
se.DoSomethingElse action
And as I write the question, my memory gets jogged,
and I begin researching a "feature" I once discovered.
This fails to work in the context of HP UFT,
but if you're running cscript, or working with Classic ASP,
you can either declare a function late, or replace a previous declaration,
to change how it works.
VBScript lets you declare the same function or subroutine
multiple times in a program.
It treats the last declaration as the correct one.
You can get around this in cscript and ASP by physically separating
the different versions of the function,
so that one doesn't get clobbered by the other.
You'll have to be careful not to put the two anywhere near each other,
or you(r successor) might have an aneurysm trying to debug the outcome.
Honestly, you're probably better served refactoring your code some other way.
Now, with the disclaimers out of the way,
the following example is for use with cscript or wscript.
Code
Since this won't work in UFT anyway, I'll write from scratch.
In WrapperSub.vbs:
' Sub WrapperSub_Payload doesn't exist in this file.
' It must be declared by the calling file or the program will crash.
Sub WrapperSub()
wscript.echo("This begins the wrapper.")
WrapperSub_Payload
wscript.echo("This ends the wrapper.")
End Sub
In WrapperSubUseA.vbs:
With CreateObject("Scripting.FileSystemObject")
call ExecuteGlobal(.openTextFile("WrapperSub.vbs").readAll())
End With
Sub WrapperSub_Payload
wscript.echo("This is payload A.")
End Sub
WrapperSub
In WrapperSubUseB.vbs:
With CreateObject("Scripting.FileSystemObject")
call ExecuteGlobal(.openTextFile("WrapperSub.vbs").readAll())
End With
Sub WrapperSub_Payload
wscript.echo("This is payload B.")
End Sub
WrapperSub
Output
>cscript wrappersubusea.vbs
Microsoft (R) Windows Script Host Version 5.8
Copyright (C) Microsoft Corporation. All rights reserved.
This begins the wrapper.
This is payload A.
This ends the wrapper.
>cscript wrappersubuseb.vbs
Microsoft (R) Windows Script Host Version 5.8
Copyright (C) Microsoft Corporation. All rights reserved.
This begins the wrapper.
This is payload B.
This ends the wrapper.
Note that if a placeholder for WrapperSub_Payload
were declared in the source file,
that placeholder would always execute instead of the intended subroutine.
This is probably due to ExecuteGlobal
executing after the current file is parsed,
causing the placeholder to load after the local declaration.
When you try this in UFT --
placing the contents of WrapperSub.vbs in a function library --
the function library rightfully ignores the caller's scope.
It will then fail because WrapperSub_Payload doesn't exist in scope.
I'm trying to use the Each keyword in For loop to enter the values in an array, but I couldn't do it in the below code, could you help me understanding the error in below code.
Dim Arr(4)
For Each Element in Arr
Element = InputBox("Enter Data")
Next
'Nothing is getting stored in the Array: Arr()
You can't set an array element using the indexer returned from For Each (*), so you'll have to do something like this instead:
Dim Arr(4)
For i = 0 to 4
Arr(i) = InputBox("Enter Data")
Next
For Each Element in Arr
MsgBox Element
Next
(*) I would guess that it's a copy of the actual value
For each loop only works for a pre-existing array data. It cannot be used for assignments.
If in case, you need to use for each loop, you can use the following method:
Dim Arr(4)
i=0
For Each Element in Arr
Arr(i)= InputBox("Enter Data")
i++
Next
I am actually not aware of the syntax, but the following concept will help you in feeding the data in the array.
I'm trying to return a dictionary from a function. I believe the function is working correctly, but I'm not sure how to utilize the returned dictionary.
Here is the relevant part of my function:
Function GetSomeStuff()
'
' Get a recordset...
'
Dim stuff
Set stuff = CreateObject("Scripting.Dictionary")
rs.MoveFirst
Do Until rs.EOF
stuff.Add rs.Fields("FieldA").Value, rs.Fields("FieldB").Value
rs.MoveNext
Loop
GetSomeStuff = stuff
End Function
How do I call this function and use the returned dictionary?
EDIT: I've tried this:
Dim someStuff
someStuff = GetSomeStuff
and
Dim someStuff
Set someStuff = GetSomeStuff
When I try to access someStuff, I get an error:
Microsoft VBScript runtime error: Object required: 'GetSomeStuff'
EDIT 2: Trying this in the function:
Set GetSomeStuff = stuff
Results in this error:
Microsoft VBScript runtime error: Wrong number of arguments or invalid property assignment.
I wasn't too sure of what was your problem, so I experimented a bit.
It appears that you just missed that to assign a reference to an object, you have to use set, even for a return value:
Function GetSomeStuff
Dim stuff
Set stuff = CreateObject("Scripting.Dictionary")
stuff.Add "A", "Anaconda"
stuff.Add "B", "Boa"
stuff.Add "C", "Cobra"
Set GetSomeStuff = stuff
End Function
Set d = GetSomeStuff
Wscript.Echo d.Item("A")
Wscript.Echo d.Exists("B")
items = d.Items
For i = 0 To UBound(items)
Wscript.Echo items(i)
Next
Have you tried doing
set GetSomeStuff = stuff
in the last line of the function?
Have you tried:
Dim returnedStuff
Set returnedStuff = GetSomeStuff()
Then "For Each" iterating over the dictionary? There's an example of using the Dictionary (albeit for VB6, the gist of it is the same though!) here.
I've inherited a large VB6 app at my current workplace. I'm kinda learning VB6 on the job and there are a number of problems I'm having. The major issue at the moment is I can't figure out how to check if a key exists in a Collection object. Can anyone help?
My standard function is very simple. This will work regardless of the element type, since it doesn't bother doing any assignment, it merely executes the collection property get.
Public Function Exists(ByVal oCol As Collection, ByVal vKey As Variant) As Boolean
On Error Resume Next
oCol.Item vKey
Exists = (Err.Number = 0)
Err.Clear
End Function
#Mark Biek Your keyExists closely matches my standard Exists() function. To make the class more useful for COM-exposed collections and checking for numeric indexes, I'd recommend changing sKey and myCollection to not be typed. If the function is going to be used with a collection of objects, 'set' is required (on the line where val is set).
EDIT: It was bugging me that I've never noticed different requirements for an object-based and value-based Exists() function. I very rarely use collections for non-objects, but this seemed such a perfect bottleneck for a bug that would be so hard to track down when I needed to check for existence. Because error handling will fail if an error handler is already active, two functions are required to get a new error scope. Only the Exists() function need ever be called:
Public Function Exists(col, index) As Boolean
On Error GoTo ExistsTryNonObject
Dim o As Object
Set o = col(index)
Exists = True
Exit Function
ExistsTryNonObject:
Exists = ExistsNonObject(col, index)
End Function
Private Function ExistsNonObject(col, index) As Boolean
On Error GoTo ExistsNonObjectErrorHandler
Dim v As Variant
v = col(index)
ExistsNonObject = True
Exit Function
ExistsNonObjectErrorHandler:
ExistsNonObject = False
End Function
And to verify the functionality:
Public Sub TestExists()
Dim c As New Collection
Dim b As New Class1
c.Add "a string", "a"
c.Add b, "b"
Debug.Print "a", Exists(c, "a") ' True '
Debug.Print "b", Exists(c, "b") ' True '
Debug.Print "c", Exists(c, "c") ' False '
Debug.Print 1, Exists(c, 1) ' True '
Debug.Print 2, Exists(c, 2) ' True '
Debug.Print 3, Exists(c, 3) ' False '
End Sub
I've always done it with a function like this:
public function keyExists(myCollection as collection, sKey as string) as Boolean
on error goto handleerror:
dim val as variant
val = myCollection(sKey)
keyExists = true
exit sub
handleerror:
keyExists = false
end function
As pointed out by Thomas, you need to Set an object instead of Let. Here's a general function from my library that works for value and object types:
Public Function Exists(ByVal key As Variant, ByRef col As Collection) As Boolean
'Returns True if item with key exists in collection
On Error Resume Next
Const ERR_OBJECT_TYPE As Long = 438
Dim item As Variant
'Try reach item by key
item = col.item(key)
'If no error occurred, key exists
If Err.Number = 0 Then
Exists = True
'In cases where error 438 is thrown, it is likely that
'the item does exist, but is an object that cannot be Let
ElseIf Err.Number = ERR_OBJECT_TYPE Then
'Try reach object by key
Set item = col.item(key)
'If an object was found, the key exists
If Not item Is Nothing Then
Exists = True
End If
End If
Err.Clear
End Function
As also advised by Thomas, you can change the Collection type to Object to generalize this. The .Item(key) syntax is shared by most collection classes, so that might actually be useful.
EDIT Seems like I was beaten to the punch somewhat by Thomas himself. However for easier reuse I personally prefer a single function with no private dependencies.
Using the error handler to catch cases when the key does not exists in the Collection can make debugging with "break on all errors" option quite annoying. To avoid unwanted errors I quite often create a class which has the stored objects in a Collection and all keys in a Dictionary. Dictionary has exists(key) -function so I can call that before trying to get an object from the collection. You can only store strings in a Dictionary, so a Collection is still needed if you need to store objects.
The statement "error handling will fail if an error handler is already active" is only partly right.
You can have multiple error handlers within your routine.
So, one could accommodate the same functionality in only one function.
Just rewrite your code like this:
Public Function Exists(col, index) As Boolean
Dim v As Variant
TryObject:
On Error GoTo ExistsTryObject
Set v = col(index)
Exists = True
Exit Function
TryNonObject:
On Error GoTo ExistsTryNonObject
v = col(index)
Exists = True
Exit Function
ExistsTryObject:
' This will reset your Err Handler
Resume TryNonObject
ExistsTryNonObject:
Exists = False
End Function
However, if you were to only incorporate the code in the TryNonObject section of the routine, this would yield the same information.
It will succeed for both Objects, and non-objects.
It will speed up your code for non-objects, however, since you would only have to perform one single statement to assert that the item exists within the collection.
Better solution would be to write a TryGet function. A lot of the time you are going to be checking exists, and then getting the item. Save time by doing it at the same time.
public Function TryGet(key as string, col as collection) as Variant
on error goto errhandler
Set TryGet= col(key)
exit function
errhandler:
Set TryGet = nothing
end function
see
http://www.visualbasic.happycodings.com/Other/code10.html
the implementation here has the advantage of also optionally returning the found element, and works with object/native types (according to the comments).
reproduced here since the link is no longer available:
Determine if an item exists in a collection
The following code shows you how to determine if an item exists within a collection.
Option Explicit
'Purpose : Determines if an item already exists in a collection
'Inputs : oCollection The collection to test for the existance of the item
' vIndex The index of the item.
' [vItem] See Outputs
'Outputs : Returns True if the item already exists in the collection.
' [vItem] The value of the item, if it exists, else returns "empty".
'Notes :
'Example :
Function CollectionItemExists(vIndex As Variant, oCollection As Collection, Optional vItem As Variant) As Boolean
On Error GoTo ErrNotExist
'Clear output result
If IsObject(vItem) Then
Set vItem = Nothing
Else
vItem = Empty
End If
If VarType(vIndex) = vbString Then
'Test if item exists
If VarType(oCollection.Item(CStr(vIndex))) = vbObject Then
'Return an object
Set vItem = oCollection.Item(CStr(vIndex))
Else
'Return an standard variable
vItem = oCollection.Item(CStr(vIndex))
End If
Else
'Test if item exists
If VarType(oCollection.Item(Int(vIndex))) = vbObject Then
'Return an object
Set vItem = oCollection.Item(Int(vIndex))
Else
'Return an standard variable
vItem = oCollection.Item(Int(vIndex))
End If
End If
'Return success
CollectionItemExists = True
Exit Function
ErrNotExist:
CollectionItemExists = False
On Error GoTo 0
End Function
'Demonstration routine
Sub Test()
Dim oColl As New Collection, oValue As Variant
oColl.Add "red1", "KEYA"
oColl.Add "red2", "KEYB"
'Return the two items in the collection
Debug.Print CollectionItemExists("KEYA", oColl, oValue)
Debug.Print "Returned: " & oValue
Debug.Print "-----------"
Debug.Print CollectionItemExists(2, oColl, oValue)
Debug.Print "Returned: " & oValue
'Should fail
Debug.Print CollectionItemExists("KEYC", oColl, oValue)
Debug.Print "Returned: " & oValue
Set oColl = Nothing
End Sub
See more at: https://web.archive.org/web/20140723190623/http://visualbasic.happycodings.com/other/code10.html#sthash.MlGE42VM.dpuf
While looking for a function like this i designed it as following.
This should work with objects and non-objects without assigning new variables.
Public Function Exists(ByRef Col As Collection, ByVal Key) As Boolean
On Error GoTo KeyError
If Not Col(Key) Is Nothing Then
Exists = True
Else
Exists = False
End If
Exit Function
KeyError:
Err.Clear
Exists = False
End Function