Dim policy_key() As RenewalClaim.PolicyKeyType
policy_key(0).policyEffectiveDt = date_format_string(ld_EffectiveDate)
Getting error at Line2.
An Error occured - Object reference not set to an instance of an object.
Each element of object arrays also needs to be declared as a new object too.
Dim policy_key() As RenewalClaim.PolicyKeyType
Redim policy_key(0)
policy_Key(0) = new RenewalClaim.PolicyKeyType
policy_key(0).policyEffectiveDt = date_format_string(ld_EffectiveDate)
QUICK TIP: When declaring classes structures etc, it is useful to name them so you can see what type they are....
e.g.
cls_Policy_Key for a class
str_Policy_Key for a structure etc.
When you come back to your code after a year.. you will thank yourself for doing so.
Dim policy_key() As RenewalClaim.PolicyKeyType
is part of your problem. When you are declaring policy_key() you are actually declaring it as an array with no elements. If you don't particularly need to use an array, for example, if you don't need to add objects to a particular element number, you might be better using a list and declaring it like this
Dim policy_key As New List(Of RenewalClaim.PolicyKeyType)
This way, you can add items easily without having to resize your array each time - The code is a little longer than Trevor's answer, but less prone to errors when you extend your code -
dim newPolicy_Key as RenewalClaim.PolicyKeyType
newPolicy_Key.policyEffectiveDt = date_format_string(ld_EffectiveDate)
policy_Key.add(newPolicyKey)
Related
I'm stuck in VBA and I couldn't find a good answer in the other questions related to error 91. I want to create an object and store variables and arrays inside that object. I tried an approach like I would do in js:
Dim block As Object
...
Set block = Nothing
block.Name = "Unbekannter Prüfblock"
block.Awf = "Unbekannter Anwendungsfall"
block.Conditions = Array()
block.Checks = Array()
I use the "Set block = Nothing" because I will use it multiple times in a loop.
But all I get is error 91 - Object variable not set
How can I set the object?
Do I really have to declare everything in vba?
Isn't there a "stop annoying me with declaration notices" toggle? ;-)
Update
Thank you all so much for the detailed answers!
As suggested I created a class for "block" and also a class for "condition" and "check". Block for example:
Option Explicit
Public name As String
Public awf As String
Public conditions As Collection
Public checks As Collection
Then I use it inside my code like this:
Dim bl As Block
Dim co As Condition
Dim ce As Check
Set bl = New Block
bl.name = ws.Range("B" & i).value
bl.awf = ws.Range("B" & i).value
Set co = New Condition
co.attr = ws.Range("B" & i).value
co.value = ws.Range("C" & i).value
bl.conditions.Add co
VBA isn't Javascript; objects and their members cannot be created inline, they need a class definition.
When you make a member call against an object, you refer to it by name, and whenever that name refers to a null reference (Nothing) you'll get error 91.
To fix it, you need to ensure every member call is made against a valid object reference. Using the Set keyword you can assign such a reference, and to create a new instance of an object you can use the New keyword followed by the name of the class that defines the type you want a new instance of:
Dim Block As Object
Block.Something = 42 ' Error 91
Set Block = New SomeClass ' set reference
Block.Something = 42 ' OK
Note that because the object is declared As Object, every member call is late-bound (resolved at run-time); if the member doesn't exist (or if there's a typo), you'll get error 438 at run-time.
You can move this error to compile-time with early binding by using a more specific data type for the declaration:
Dim Block As SomeClass
Because the members of SomeClass are known at compile-time, the IDE will now provide you with a member completion list when you type up a member call, and typos will no longer be valid at compile-time: strive to remain in the early-bound realm whenever possible! Note: As Variant (explicit or not) is also similarly late-bound.
So we add a new class module and call it SomeClass and we add a couple of public fields:
Option Explicit
Public Name As String
Public Case As String
Public Condition As Variant
Public Check As Variant
And now you can create and consume a new instance of that class, and add instances of it to a collection to process later (note: you can't do that with a UDT/Type).
The VBIDE settings have an annoying option ("automatic syntax check", IIRC) that immediately pops a message box whenever there's a compilation error on the current line; uncheck it (invalid lines will appear in red, without a message box), but do have the "require variable declaration" setting checked: it will add Option Explicit to every module, and that will spare you from a number of easily avoidable run-time errors, moving them to compile-time.
In JS, you can add properties (together with values) on the fly to an object. That's not possible in VBA (and most other languages).
Your declaration Dim block As Object is defining a variable that is supposed to point to an Object. But it isn't pointing to anything yet, per default it is initialized with Nothing, which is, literally, nothing, and has neither properties nor methods, it's just a placeholder to signal "I don't point to anything yet". Furthermore, Object cannot be instantiated.
in VBA, you assign something to an object variable with Set (this is different to most other languages). If you want to create a new object, you use the keyword New.
However, before you do that, you need to know what kind of object (which class) you need. This can be an existing class, eg a Worksheet or a Range in Excel, or it can be an own defined class (by creating a new class module in your code). In any case, you need to define the properties and the methods of that class. Considering the most simple class module Class1 (of course you should think about a more usefull name):
Option Explicit
Public name as String
Public case as String
(I will not start to talk about private members and getter and setter).
You then write
Dim block As Class1
Set block = New Class1
block.name = "Unbekannter Prüfblock"
(But block.data = "Hello world" will not be possible as data is not a member of your class.)
Big advantage of this attempt is that the compiler can show you when you for example mistyped a property name before you even start your code (Debug->Compile). In JS, you will get either a runtime error or a new property on the fly - hard to find nasty bugs.
If you later need a new (empty) object, just create a new object using New. If the old object is not referenced anywhere else, the VBA runtime will take care that the memory is freed (so no need to write Set block = Nothing).
In case you really don't know the properties in advance (eg when you read XML or JSON files or a key-value list from an Excel sheet...), you can consider to use a Collection or a Dictionary. Plenty of examples on SO and elsewhere.
One remark to block.Condition = Array(). Arrays in VBA are not really dynamic, you cannot add or remove entries easily during runtime. In VBA, you have static and dynamic arrays:
Dim a(1 to 10) as String ' Static array with 10 members (at compile time)
Dim b() as String ' Dynamic array.
However, for dynamic members you need to define how many members you need before you write something into it, you use the ReDim statement for that. Useful if you can calculate the number of members in advance:
Redim b(1 to maxNames) ' Dynamic array, now with maxNames members (whatever maxNames is)
You can change the array size of a dynamic array with Redim Preserve, but that should be an exception (bad programming style, inperformant). Without Preserve, you will get a new array, but the former data is lost.
Redim Preserve b(1 to maxNames+10) ' Now with 10 more members.
If you really don't know the number of members and it can change often during runtime, again a Collection or a Dictionary can be the better alternative. Note that for example a Dictionary can itself a Dictionary as value, which allows to define Tree structures.
Regarding your issue adding to the collection:
You need to add this code to your class module "Block" - only then you can add objects to the collections
Private Sub Class_Initialize()
Set conditions = New Collection
set checks = new Collection
End Sub
I am creating what I believe is the way to create dynamic dims e.g.
Dim browser(DataGridView1.Rows(e.RowIndex).Cells(0).Value)
which basically is creating a something like Dim browser(1)
However I am trying to write a test button to call this browser by using:
browser1.load("http://google.com")
and I have even tried
browser(1).load("http://google.com"
I get the browser part underlined.
What is the correct way to reference them?
I'm not sure what the end goal is, but this construct:
Dim browser(1)
Is effectively the same as:
Dim browser(1) as Object
i.e. it's creating an array of Object of length 2, which is fine in that it can hold anything but makes your life pointlessly hard because you then have to cast the contents every time you want to do something with them; it's bad enough storing a single thing (such as a web browser widget) as an Object:
'this is bad
Dim browser as Object = New WebBrowserWidget
Because you have to cast it every time you use it (when Option Strict is On, which is really the only way you should ever program)
DirectCast(browser, webBrowserWidget).Load("http://google.com)
But to then add the indirection of storing it in an array:
'this is worse
Dim browser(1) as Object
browser(0) = New WebBrowserWidget
browser(1) = New WebBrowserWidget
And casting them to use them:
DirectCast(browser(0), webBrowserWidget).Load("http://google.com)
Just give these things a proper type when you declare them, or use type inference by providing something on the right hand side of an = that is a particular type:
'infer the type from the right hand side
Dim browser = New WebBrowserWidget
'or declare, give a type and create a new instance to assign to it
Dim browser as New WebBrowserWidget
Then it's a lot easier to use it, because Intellisense will know it's a browser and offer you help with the methods and properties, such as Load:
browser.Load("http://google.com")
If you code with Option Strict Off then you can store things in an object and just cross your fingers and hope you get everything right when youre coding, but it's like writing javascript - fumbling round eyes closed not knowing whether you got it right til it blows up at runtime:
Dim x as Object = New WebBrowserWidget
x.Load(...) 'don't get any intelllisense for this, but it'll work at runtime
x.Laod(...) 'dont get any compiler error even though this is a typo - it'll just explode at runtime
I used to have the following working code
Set result = DecodeJson(MyRequest.responseText)
Dim keys() As String
keys = GetKeys(result.issues)
Now, my approach has changed and instead of having result being the object, I receive a Collection based upon Array of class objects as class member in VBA
Dim resultsFromQueries As Collection
Set resultsFromQueries = GetAllJSonObjects(searchString) ' this calls DecodeJson(MyRequest.responseText) as per the code snippet above
Dim i As Integer
For i = 0 To resultsFromQueries.Count
Dim keys() As String
Dim item As Object
Set item = resultsFromQueries.item(i + 1) ' I guess it's not 0 based?
keys = GetKeys(item.result.issues) 'KABOOM
The issue I have now is I keep getting the following exception
Run time error '424':
Object required
Checking in the watch window, item shows as type Variant/String and has the value of "[object Object]"
Do I need to cast it?
I had that problem just a few weeks ago, the problem was the following:
The collection was collected with the follwing code:Collection.Add(OBJECT)
This however leads to the addition of the value of the Object into the Collection and can be solved as simple as leaving the parathesis.Collection.add OBJECT
So my advice is to go into the GetAllJSonObjects(searchString) function and
search for the addition process and make sure that it is without parethesis.
Like this the Collection will contain Objects and not variants and your code with item(i+1) should work properly.
Good luck!
Running into problems creating objects through reflection and then running them on multiple threads.
I just cannot seem to figure out what I need to here:
For Each WorkerNode As XmlNode In oRunSettings.GetWorkerValues
Dim sWorkerName = WorkerNode.Attributes(SETTING_NAME_ID).Value
Dim oWorkerType As Type = Type.GetType(String.Format("Worker.{0}", sWorkerName))
Dim oWorker As Object = Activator.CreateInstance(oWorkerType)
Dim tWorker As Thread = New Thread(AddressOf oWorker.Process)
tWorker.Start()
Next
It is causing errors at the "AddressOf" because Object does not have a method called that. Do I need to do something with an interface?
First of all I want to say that I've never wrote code in VB so I can be completely wrong here but I'll try anyway.
It seems that you hold the created instance as Object instead of it's correct type.
Object does not contain method named Process, hence the error.
try casting the object to the correct type.
I hate when people answer their own question, but while waiting for an answer, I realized that I could just cast the object as its base object, and set the reflection from there. That is working now.
I have this code to return a list of fund sources for our organization.
Dim FundSourceList As New List(Of FundSource)
Dim fs As New FundSource
If results.Count > 0 Then
For Each result In results
fs.FundID = result.Item("strFundID")
fs.FundDescription = result.Item("txtFundIDDescr")
fs.ShortFundDescription = result.Item("txtFundIDDescrShort")
FundSourceList.Add(fs)
Next
End If
Return FundSourceList
The problem is that when I loop through the resulting FundSourceList all it shows is the last value. For example, if I have three fund sources (state, federal, athletic), then when I use this code to loop through all I get listed is athletic, athletic, athletic.
For Each FundSource In FundSources
Debug.Print(FundSource.FundDescription)
Next
So I change the code to this. I moved the creation of the fs variable inside the loop.
Dim results = From result In dsResult.Tables(0) Select result
Dim FundSourceList As New List(Of FundSource)
If results.Count > 0 Then
For Each result In results
Dim fs As New FundSource
fs.FundID = result.Item("strFundID")
fs.FundDescription = result.Item("txtFundIDDescr")
fs.ShortFundDescription = result.Item("txtFundIDDescrShort")
FundSourceList.Add(fs)
Next
End If
Return FundSourceList
This works fine but now I'm creating a new class over and over again. It seems a little inefficient to me. Can I not create the class outside the loop and use it over and over again? Thanks.
If you have 3 fund sources, you need three FundSource objects. It's as simple as that. I don't know what's inefficient about it...
How can you add 3 fund sources to your list but just create one?
You're not actually creating a class - the class is the code definition for the methods and properties. When you use the New operation, you're creating an instance of that class, which results in an object. When you have a list of objects, like FundSourceList, you want the items in it to be individual objects. So yes, the solution you have at the bottom is correct. You mention efficiency concerns - when you instantiate the object, basically all that is happening (in this case) is some memory is being allocated to store the variables (and some references for the managed memory, but you don't need to worry about that here). This is necessary and is optimized under-the-hood, so you shouldn't need to worry about that either.
You can't instantiate the object outside of the loop to achieve the result you're after.
This is because your object would be a reference type.
By instantiating outside of the loop, you would create one reference to your object.
When iterating through your results and setting the properties, you'll be using that same reference over and over.
All you're adding to the list on each iteration is the same reference, which by the end of the loop, will refer to an object containing the last values in your result set.
By creating new objects inside the loop, you create new references - each pointing to a new FundSource. Your loop now writes into a fresh object, and get your desired results.