I'm trying to write a language independent filter for MS Project in VBA. I'm using the syntax:
FilterEdit (Name, Taskfilter, Create, Fieldname, Test, Value, Operation...)
I have managed to get the Fieldnames and Tests to be language independent, but I struggle with the Operation:= expression. For an English locale one would write: Operation:="and" but that doesnt work for other locales.
Is there a way to write the logical operator (and/or) as an enumeration? (not as a string?)
For Excel one could write xlAnd, and Project has a lot of enumerations starting with Pj, ie. PjTaskStart. I also know there's a Filter.LogicalOperationType, but I haven't managed to figure out if this could work for me or not. I have also experimented with FieldConstantToFieldName, but I reckon there's no fieldname for the logical operator?
I know I could use If LocaleID = xxxx Then..., but I'd like to not assume what locales will be in use.
Edit: I solved the first part of my problem!
By leaving it blank Operation:="", Project returns "And". But I haven't figured out yet how to return "Or"...
Operation:="" works for FilterEdit, but not for SetAutoFilter.
So I ended up using the dreaded If LocaleID.
Teaching moment:
I found out most operators can be language independent, except for:
And, Or, Contains and Does Not Contain.
These needs to be translated for each locale. I'll get to those in a minute. First I'll list all the language independent operators:
< Less than <= Less than or equal to > Greater than >= Greater than or equal to = Equal to <> Not equal to
My trick for finding the translations I need for the language dependent operators is the following MS Office Support page.
Notice the category named "Filter for specific text" in the English support page. Here we can read all the "words" we need. Now go to the bottom of the web page and change the language:
This opens up a new page listing all the different languages (not locale specific). Remembering where you found the word for Contains in English, then changing the language to for instance "Magyar (Magyarorzág)", we can now see that Contains = "Tartalmazza" in Magyar.
Next step is to google "Magyar languge" and learn that this actually equals Hungarian. So now you can go to this MSDN web page to see that Hungarian = LocaleID: 1038.
Putting all this together inside VBA makes you have to write the following code:
Dim LocalContains As String
If LocaleID = 1038 Then
LocalContains = "Tartalmazza" 'Hungarian
ElseIf LocaleID = 1044 Then
LocalContains = "inneholder" 'Norwegian
Else
LocalContains = "contains" 'English
End If
Related
The large majority of SonarLint rules that I've come across in Java seemed plausible and justified. However, ever since I've started using SonarLint for VB.NET, I've come across several rules that left me questioning their usefulness or even whether or not they are working correctly.
I'd like to know if this is simply a problem of me using some VB.NET constructs in a suboptimal way or whether the rule really is flawed.
(Apologies if this question is a little longer. I didn't know if I should create a separate question for each individual rule.)
The following rules I found to leave some cases unconsidered that would actually turn up as false-positives:
S1871: Two branches in the same conditional structure should not have exactly the same implementation
I found this one to bring up a lot of false-positives for me, because sometimes the order in which the conditions are checked actually does matter. Take the following pseudo code as example:
If conditionA() Then
doSomething()
ElseIf conditionB() AndAlso conditionC() Then
doSomethingElse()
ElseIf conditionD() OrElse conditionE() Then
doYetAnotherThing()
'... feel free to have even more cases in between here
Else Then
doSomething() 'Non-compliant
End If
If I wanted to follow this Sonar rule and still make the code behave the same way, I'd have to add the negated version of each ElseIf-condition to the first If-condition.
Another example would be the following switch:
Select Case i
Case 0 To 40
value = 0
Case 41 To 60
value = 1
Case 61 To 80
value = 3
Case 81 To 100
value = 5
Case Else
value = 0 'Non-compliant
There shouldn't be anything wrong with having that last case in a switch. True, I could have initialized value beforehand to 0 and ignored that last case, but then I'd have one more assignment operation than necessary. And the Java ruleset has conditioned me to always put a default case in every switch.
S1764: Identical expressions should not be used on both sides of a binary operator
This rule does not seem to take into account that some functions may return different values every time you call them, for instance collections where accessing an element removes it from the collection:
stack.Push(stack.Pop() / stack.Pop()) 'Non-compliant
I understand if this is too much of an edge case to make special exceptions for it, though.
The following rules I am not actually sure about:
S3385: "Exit" statements should not be used
While I agree that Return is more readable than Exit Sub, is it really bad to use a single Exit For to break out of a For or a For Each loop? The SonarLint rule for Java permits the use of a single break; in a loop before flagging it as an issue. Is there a reason why the default in VB.NET is more strict in that regard? Or is the rule built on the assumption that you can solve nearly all your loop problems with LINQ extension methods and lambdas?
S2374: Signed types should be preferred to unsigned ones
This rule basically states that unsigned types should not be used at all because they "have different arithmetic operators than signed ones - operators that few developers understand". In my code I am only using UInteger for ID values (because I don't need negative values and a Long would be a waste of memory in my case). They are stored in List(Of UInteger) and only ever compared to other UIntegers. Is this rule even relevant to my case (are comparisons part of these "arithmetic operators" mentioned by the rule) and what exactly would be the pitfall? And if not, wouldn't it be better to make that rule apply to arithmetic operations involving unsigned types, rather than their declaration?
S2355: Array literals should be used instead of array creation expressions
Maybe I don't know VB.NET well enough, but how exactly would I satisfy this rule in the following case where I want to create a fixed-size array where the initialization length is only known at runtime? Is this a false-positive?
Dim myObjects As Object() = New Object(someOtherList.Count - 3) {} 'Non-compliant
Sure, I could probably just use a List(Of Object). But I am curious anyway.
Thanks for raising these points. Note that not all rules apply every time. There are cases when we need to balance between false positives/false negatives/real cases. For example with identical expressions on both sides of an operator rule. Is it a bug to have the same operands? No it's not. If it was, then the compiler would report it. Is it a bad smell, is it usually a mistake? Yes in many cases. See this for example in Roslyn. Should we tune this rule to exclude some cases? Yes we should, there's nothing wrong with 2 << 2. So there's a lot of balancing that needs to happen, and we try to settle for an implementation that brings the most value for the users.
For the points you raised:
Two branches in the same conditional structure should not have exactly the same implementation
This rule generally states that having two blocks of code match exactly is a bad sign. Copy-pasted code should be avoided for many reasons, for example if you need to fix the code in one place, you'll need to fix it in the other too. You're right that adding negated conditions would be a mess, but if you extract each condition into its own method (and call the negated methods inside them) with proper names, then it would probably improves the readability of your code.
For the Select Case, again, copy pasted code is always a bad sign. In this case you could do this:
Select Case i
...
Case 0 To 40
Case Else
value = 0 ' Compliant
End Select
Or simply remove the 0-40 case.
Identical expressions should not be used on both sides of a binary operator
I think this is a corner case. See the first paragraph of the answer.
"Exit" statements should not be used
It's almost always true that by choosing another type of loop, or changing the stop condition, you can get away without using any "Exit" statements. It's good practice to have a single exit point from loops.
Signed types should be preferred to unsigned ones
This is a legacy rule from SonarQube VB.NET, and I agree with you that it shouldn't be enabled by default in SonarLint. I created the following ticket in our JIRA: https://jira.sonarsource.com/browse/SLVS-1074
Array literals should be used instead of array creation expressions
Yes, it seems to be a false positive, we shouldn't report on array creations when the size is explicitly specified. https://jira.sonarsource.com/browse/SLVS-1075
I'm hoping someone can help answer my question, perhaps with an idea of where to go or whether what I'm trying to do is not possible with the way I want to do it.
I've been asked to write a set of rules based on the data held by our ERP form components or variables.
Unfortunately, these components and variables cannot be accessed or used outside of the ERP, so I can't use SQL to query the values and then build some kind of SQL query.
They'd like the ability to put statements like these:
C(MyComponentName) = C(MyOtherComponentName)
V(MyVariableName) > 16
(C(MyComponentName) = "") AND V(MyVariableName) <> "")
((C(MyComponentName) = "") OR C(MyOtherComponentName) = "") AND V(MyVariableName) <> "")
This should be turned into some kind of query which gets the value of MyComponentName and MyOtherComponentName and (in this case) compares them for equality.
They don't necessarily want to just compare for equality, but to be able to determine whether a component / variable value is greaterthan or lessthan etc.
Basically it's a free-form statement that gets converted into something similar to an IF statement.
I've tried this:
Sub TestCondition()
Dim Condition as string = String.Format("{0} = {1}", _
Component("MyComponent").Value, Component("MyOtherComponent").Value)
If (Condition) Then
' Do Something
Else
' Do Something Else
End If
End Sub
Obviously, this does not work and I honestly didn't think it would be so simple.
Ignoring the fact that I'd have to parse the line, extract the required operators, the values from components or variables (denoted by a C or V) - how can I do this?
I've looked at Expression Trees but these were confusing, especially as I'd never heard of them, let alone used them. (Is it possible to create an expression tree for dynamic if statements? - This link provided some detail on expression trees in C#)
I know an easier way to solve this might be to simply populate the form with a multitude of drop-down lists, so users pick what they want from lists or fill in a text box for a specific search criteria.
This wouldn't be a simple matter as the ERP doesn't allow you to dynamically create controls on its forms. You have to drag each component manually and would be next to useless as we'd potentially want at least 1 rule for every form we have (100+).
I'm either looking for someone to say you cannot do this the way you want to do it (with a suitable reason or suggestion as to how I could do it) that I can take to my manager or some hints, perhaps a link or 2 pointing me in the right direction.
If (Condition) Then
This is not possible. There is no way to treat data stored in a string as code. While the above statement is valid, it won't and can't function the way you want it to. Instead, Condition will be evaluated as what it is: a string. (Anything that doesn't boil down to 0 is treated as True; see this question.)
What you are attempting borders on allowing the user to type code dynamically to get a result. I won't say this is impossible per se in VB.Net, but it is incredibly ambitious.
Instead, I would suggest clearly defining what your application can and can't do. Enumerate the operators your code will allow and build code to support each directly. For example:
Public Function TestCondition(value1 As Object, value2 As Object, op as string) As Boolean
Select Case op
Case "="
Return value1 = value2
Case "<"
Return value1 < value2
Case ">"
Return value1 > value2
Case Else
'Error handling
End Select
End Function
Obviously you would need to tailor the above to the types of variables you will be handling and your other specific needs, but this approach should give you a workable solution.
For my particular requirements, using the NCalc library has enabled me to do most of what I was looking to do. Easy to work with and the documentation is quite extensive - lots of examples too.
In VB.NET, there's no == operator for comparison, so the = operator serves that purpose as well as assignment. I have a function, and I want it to return the boolean result of a comparison, without storing that result in a variable:
Private Function foo() As Boolean
Dim bar As Integer = 1
Return bar = 2
End Function
Returns: False
OK, but what's the value of bar?
Private Function foo() As KeyValuePair(Of Boolean, Integer)
Dim bar As Integer = 1
Return New KeyValuePair(Of Boolean, Integer)(bar = 2, bar)
End Function
Returns: False, 1
It looks like = will perform a comparison when the statement context demands it, but is this guaranteed? That is, can I be sure that bar will never be set to 2 in this situation?
Also, I know that VB.NET doesn't allow chained inline assignments, which may be for the best. Does this odd = behavior cause any other quirks I should be aware of?
You cannot do in-line assignments in VB, Assignment is an explicit statement:
[Let] <<target-reference>> = <<value-expression>>
The Let is optional and implicit, and hardly ever used anymore. The general rule that you can use to distinguish the [Let] command from equality testing is that for Let, no other keyword may come before the target-reference in the statement. AFAIK, in all cases of = as equality testing, there is one or more other keywords that precede it in the statement.
In your first example, the keyword Return precedes your =, so it's an equality test, and not an assignment.
In your first example you can do either:
Return 2
or
bar = 2
Return bar
As for your question "OK, but what's the value of bar?", bar still equals one.
= in VB cause no quirks. It works exactly as documented, and it always has (including its predecessor, BASIC back to 1968).
If you are starting to code in VB (coming from a language like C#), you should start getting used to the peculiar VB way of doing things; which is based on the idea: as simple and intuitive for the programmer as possible. "If assignation and comparison happen always in different contexts, why not using the same operator and let the context define its exact meaning?" -> VB-way of seeing things. "No, different realities have to be accounted for by different operators. End of the discussion" -> C#-way. :)
Is this reliable? Can you blindly trust on these not-always-clear-for-a-programmer bits? Sure, VB.NET peculiarities are highly-reliable and trustworthy. You can always use = (or Is on some contexts, but VS would tell you) and be completely sure that the code will do what is expected. But the question is: are you sure that you write exactly what you want?
This last question is what, perhaps, is more criticable of VB and what might give some problems to programmers from other languages: the higher the flexibility, the more likely is that you make an error; mainly if you are used to a different format.
Regarding the chained inline assignments, I honestly don't see its true utility (and never use them in C#). Regarding other differences with respect to C#, there are plenty of them; in some cases, I think that the C# approach is better; other times, the VB.NET one. On readability/length of code, I can refer to the With Statement I have always found somehow useful which is not present in C#.
One way to have 100% sure that the expression will be evaluated as an boolean expression is to use ()
e.g
Dim a = 2
Return (a = 1)
Since you cannot set a value to a variable wihtin the parenthesis.
What i want to say is: on an return statament for example you cant assing a value to a variable so, even if you use
a = 1
The compilator knows that this expression only can be an boolean expression.
The same to the if statament and so on..
Heh back in QB45 days we used to exploit the fact that "True" was the numeric value -1. So you would see code like x = 1 - x * (x < 6) (translation: increment x, but reset to 1 when it gets to 6)
I have following sample code
Dim q As Char = "a"
Dim res As String = CStr(AscW(q))
res contains correctly "97" but when I use AscW(q) in watch or immediate it returns message: Cannot convert to 'Integer'.
Is it a bug or Visual Studio or am I doing something not correctly?
How can I see a character code in Immediate.
Note
The code presented is just an example. I found the problem when trying to see Character code in the Watch Window.
For a workaround, how about the command
? System.Text.Encoding.Unicode.GetBytes(q)
I personally believe that any acceptable VB.Net code should be acceptable in the Immediate window and really don't understand why AscW is causing errors when VB.Net offers no equivalent (e.g. in C#, but not VB.Net, you can cast a Char variable to an Integer to get the character code).
You are doing everything right (and the outputs will be OK in any case), although you are using old VB code. If you need functionalities like AscW (, Asc, ChrW, etc.), you would have to rely on this "old code" to get what you want (directly or via Microsoft.VisualBasic.Strings which, btw, does not show a different behaviour). But, in any other case, you should avoid the utilisation of this old code.
Test these two lines in the Immediate Window:
Dim res As String = CStr(5)
res = 5.ToString()
As you can see, you get an "error" (VS 2010, right-click on the line and select "QuickWatch") in the first line (old version), but not in the second one (.NET version).
Thus, the behaviour you observed can be considered as an inoffensive bug (no real effects in the execution) more or less understandable if you analyse the situation (you are asking a certain language (VB.NET) to support all its own features and the ones from an old language (VB); with the old one, some secondary functionalities might not be perfect).
I set the culture to Hungarian language, and Chr() seems to be broken.
System.Threading.Thread.CurrentThread.CurrentCulture = "hu-US"
System.Threading.Thread.CurrentThread.CurrentUICulture = "hu-US"
Chr(254)
This returns "ţ" when it should be "þ"
However, Asc("ţ") returns 116.
This: Asc(Chr(254)) returns 116.
Why would Asc() and Chr() be different?
I checked and the 'wide' functions do work correctly: ascw(chrw(254)) = 254
Chr(254) interprets the argument in a system dependent way, by looking at the System.Globalization.CultureInfo.CurrentCulture.TextInfo.ANSICodePage property. See the MSDN article about Chr. You can check whether that value is what you expect. "hu-US" (the hungarian locale as used in the US) might do something strange there.
As a side-note, Asc() has no promise about the used codepage in its current documentation (it was there until 3.0).
Generally I would stick to the unicode variants (ending on -W) if at all possible or use the Encoding class to explicitly specify the conversions.
My best guess is that your Windows tries to represent Chr(254)="ţ" as a combined letter, where the first letter is Chr(116)="t" and the second ("¸" or something like that) cannot be returned because Chr() only returns one letter.
Unicode text should not be handled character-by-character.
It sounds like you need to set the code page for the current thread -- the current culture shouldn't have any effect on Asc and Chr.
Both the Chr docs and the Asc docs have this line:
The returned character depends on the code page for the current thread, which is contained in the ANSICodePage property of the TextInfo class. TextInfo.ANSICodePage can be obtained by specifying System.Globalization.CultureInfo.CurrentCulture.TextInfo.ANSICodePage.
I have seen several problems in VBA on the Mac where characters over 127 and some control characters are not treated properly.
This includes paragraph marks (especially in text copied from the internet or scanned), "¥", and "Ω".
They cannot always be searched for, cannot be used in file names - though they could in the past, and when tested, come up as another ascii number. I have had to write algorithms to change these when files open, as they often look like they are the right character, but then crash some of my macros when they act strangely. The character will look and act right when I save the file, but may be changed when it is reopened.
I will eventually try to switch to unicode, but I am not sure if that will help this issue.
This may not be the issue that you are observing, but I would not rule out isolated problems with certain characters like this. I have sent notes to MS about this in the past but have received no joy.
If you cannot find another solution and the character looks correct when you type it in, then I recommend using a macro snippet like the one below, which I run when updating tables. You of course have to setup theRange as the area you are looking at. A whole file can take a while.
For aChar = 1 To theRange.Characters.count
theRange.Characters(aChar).Select
If Asc(Selection.Text) = 95 And Selection.Text <> "_" Then Selection.TypeText "Ω"
Next aChar