How to get the value from method in Visual Basic 6 - vb6

The code below returns error after the return statement
Private Sub Command1_Click()
Dim str As String
str = display("test")
MsgBox (str)
End Sub
Public Function display(s As String) As String
s = "updated"
Return s
End Function
Any ideas why?

Change display function. The difference is that in vb6 functions return a value not with return, but with it's name(in this case display), like below.
Public Function display(s As String) As String
s = "updated"
display = s
End Function

Related

How to pass an array with fixed length strings to a function

I am trying to pass an array of fixed length strings to a function. However, the function will not know the size of the strings. The parameter should take any size strings. How would I go about this? Here is my code:
Public Type myRecord
names(15) As String * 250
End Type
Function def:
Function HasQuotes(textArr() As String) As String
End Function
Usage:
HasQuotes(rowRec.names)
where rowRec is a MyRecord.
When I run this code I get the following error Type Mismatch: array or user defined type expected. This is because the parameter is not defined as textArr() As String * 250. How can I make the parameter accept any string length?
You Have to follow Proper syntax you can Try Following updated Code
Private Type myRecord
names(15) As String * 250
End Type
Private Sub Command1_Click()
Dim rowRec As myRecord
rowRec.names(0) = ("Vaibhav")
Dim v As String
v = HasQuotes(rowRec.names)
End Sub
Function HasQuotes(ByRef textArr() As String * 250) As String
MsgBox textArr(0)
End Function
You are going to have trouble passing an array of fixed-length strings of any length. One simple solution is to convert them to an array of variable-length strings:
Private Sub Test()
Dim rowRec As myRecord
Dim names(15) As String
Dim i As Integer
Dim s As String
rowRec.names(0) = "Brian"
rowRec.names(15) = "Stafford"
'move the data to an array of variable-length strings
For i = 0 To 15
names(i) = rowRec.names(i)
Next
s = HasQuotes(names)
'move the data back to the original array if needed
For i = 0 To 15
rowRec.names(i) = names(i)
Next
End Sub

vb6 collection exist and boolean value set

I am new to vb6 so might be obvious for some of you.I have a collection problem, trying to put items in a collection to then evaluate if the item exists and setting a button to be enabled or not.
The Code:
For Each vBookmark In lstAssign.SelBookmarks
'---------------------------------------
'filtering with agency code and crew code.
sAssignmentValue = lstAssign.columns("AgencyCode").Value & lstAssign.columns("CrewCode").Value
'Show/hide value depending on crew existance.
If Not ExistsStartLocation(colParameters, sValue) Then
bEnableMyButton = True
colParameters.Add (sValue)
Else
bEnableMyButton = False
End If
'----------------------------------------
Next
sAssignmentValue = ""
tbrMain.TbrButtonEnabled "XXX", bEnableMyButton
tbrMain.TbrButtonEnabled "YYY", bEnable
Set colStartLocationParameters = Nothing
Exit Sub
Private Function ExistsStartLocation(col As collection, index As Variant) As Boolean
On Error GoTo ErrHandler
Dim v As Variant
v = col(index)
ExistsStartLocation = True
Exit Function
ErrHandler:
ExistsStartLocation = False
End Function
The problem is at this moment is that I only have colParameters(index) accessible, so I can't access my collection with a value "123-ABC" directly. I do not want to add an integer index, I want to keep simply accessing by item value, but my exists method will always return false. therefore always disabling my button.
How does this works?
At first glance, you should have to do something like this:
Private Function ExistsStartLocation(col As collection, val As String) As Boolean
Dim blnFoundItem As Boolean = False
For index As Integer = 1 To col.Count
If col(index) = val Then
blnFoundItem = True
End If
Next
ExistsStartLocation = blnFoundItem
End Function
Looping the collection works but is not efficient. If you assign the optional Key value in the Add method you can also use that as the Index to the Item method. In your example it appears you are assigning a string to the collection so the Add method would look something like ...
colParameters.Add sValue, sValue
Be aware though that if you are adding duplicate values this won't work. The keys need to be unique.
With the the collection item's key populated you can use a function that leverages the err object. If you try to get a collection item by the key and it exists no error is thrown. If it does not exists err.number 5 is thrown. The new function would be something like this.
Public Function ItemExists(ByVal vCollection As Collection, ByVal vKey As String) As Boolean
Dim varItem As Variant
On Error Resume Next
varItem = vCollection.Item(vKey)
ItemExists = (Err.Number = 0)
End Function

Difference between Function and Sub procedures in VB6

I cant understand about the difference between Function and Sub procedures in VB.NET.
The one with Function :
Private Function remainder (intno1 As Integer, intno2 As _ Integer) As Integer
Dim intresult As Integer
intresult = intno1 Mod intno2
remainder = intresult
End Function
and then by this way i call it :
Private Sub cmdrem _Click()
Dim intm As Integer, intn As Integer
Dim intmod As Integer
intm = Val (txtno1.Text)
intn = Val (txtno2.Text)
intmod = remainder (intm, intn)
lblres.text = "Answer Is = " + Str(intmod)
End Sub
would you please help me ?
some main differences between procedure and function in vb are that the function returns a value but sub procedure never returns value.
the return type must be defined in function declaration.
A function always is declared with keyword Function and a sub procedure is declared with keyword Sub.
Function ends with the keyword end function
and procedure ends with keyword end sub.

How to pass the string value to function

I want to pass the string value to function
Function Code
Private Function Assign(Div As String)
sSQL = "Insert into table2 Select * from table1 Where Divi_Code = '" & Div & "'"
Rdoconn.Execute sSQL, rdExecDirect
End Function
Button Click Code
Dim Div as string
Div = "Hai,Howareyou"
Assign Div 'Getting Error as "ByRef arguement type mismatch"
The above code is shwoing error as Getting Error as "ByRef arguement type mismatch"
I tried the following code, and I am not getting any ByRef argument mismatch.
Private Function Assign(Div As String)
ssql = "Insert into table2 Select * from table1 Where Divi_Code = '" & Div & "'"
MsgBox ssql
End Function
Private Sub Command1_Click()
Dim Div As String
Div = "Hai,Howareyou"
Assign Div
End Sub
I am really puzzled why your code is giving you an error. However, there are a couple of things you should change in your code and I'm confident this will resolve your problem:
The function parameter should be declared ByVal. In VB6, parameters are ByRef by default unless specified. This means that the function call could have side-effects in the parent procedure if for any reason the parameter Div is modified. Always use ByVal unless you really need to modify the parameter value:
Private Function Assign(ByVal Div As String)
Is there any reason why you declared Assign as a Function? Are you intending to return a value? If not, you should use Private Sub instead of Private Function (and End Sub at the end). This is equivalent to using the void return type in C. For your reference, you should always define the return type of your functions in VB6, otherwise Variant will be assumed. The return type can be fined in functions using the "As" keyword at the end of the declaration:
Private Function Add(ByVal n1 as Integer, ByVal n2 As Integer) As Integer
One last thing I'd like to add is that you never, ever should concatenate variables to SQL queries like this. At the very least, the code will crash if the name contains an apostrophe (ex: try calling it with "I'm very well"), and at worst, you'll be opening up for SQL injection attacks where someone could use this to run specially crafted queries on your database. While I'm not familiar with RDO, you should check out MSDN - this article mentions how to create parameter queries with RDO.
To call a Function declared as
Private Function AssignDiv(Div As String, Dep As String)
you'd need something like
AssignDiv Div, "WhatEverDep"
Your
Assign Div
is completely wrong.
You changed your declaration to
Private Function AssignDiv(Div As String)
but the function's name is still wrong.
You changed your code again. Now names and parameters match, so if you still get an error, it's not caused by the code you published.
to begin with I don't understand why you are setting you Div value and then passing it into your function, you may as well pass it in directly on the button click, and then also I can't see that sSQL is actually defined as a string, please try the following code:
Public Function Assign(strDiv As String)
Dim sSQL As String
sSQL = "Insert into table2 Select * from table1 Where Divi_Code = '" & strDiv & "'"
Rdoconn.Execute sSQL, rdExecDirect
End Function
And then call from the button click as:
Private Sub Command1_Click()
Call Assign("Hai,Howareyou")
End Sub

Overload constructors in VBScript

I found a way to extend classes in VBScript, but are there any ways to pass in parameters or overload the constructor? I am currently using an Init function to initialize the properties, but would like to be able to do this when I create the object.
This is my sample class:
Class Test
Private strText
Public Property Get Text
Text = strText
End Property
Public Property Let Text(strIn)
strText = strIn
End Property
Private Sub Class_Initialize()
Init
End Sub
Private Sub Class_Terminate()
End Sub
Private Function Init
strText = "Start Text"
End Function
End Class
And I create it
Set objTest = New Test
But would like to do something like this
Set objTest = New Test(strInitText)
Is this possible, or does the object have to be created and initialized in two setps?
Just to alter slightly on svinto's method...
Class Test
Private m_s
Public Default Function Init(s)
m_s = s
Set Init = Me
End Function
Public Function Hello()
Hello = m_s
End Function
End Class
Dim o : Set o = (New Test)("hello world")
Is how I do it. Sadly no overloading though.
[edit]
Though if you really wanted to you could do something like this...
Class Test
Private m_s
Private m_i
Public Default Function Init(parameters)
Select Case UBound(parameters)
Case 0
Set Init = InitOneParam(parameters(0))
Case 1
Set Init = InitTwoParam(parameters(0), parameters(1))
Else Case
Set Init = Me
End Select
End Function
Private Function InitOneParam(parameter1)
If TypeName(parameter1) = "String" Then
m_s = parameter1
Else
m_i = parameter1
End If
Set InitOneParam = Me
End Function
Private Function InitTwoParam(parameter1, parameter2)
m_s = parameter1
m_i = parameter2
Set InitTwoParam = Me
End Function
End Class
Which gives the constructors...
Test()
Test(string)
Test(integer)
Test(string, integer)
which you can call as:
Dim o : Set o = (New Test)(Array())
Dim o : Set o = (New Test)(Array("Hello World"))
Dim o : Set o = (New Test)(Array(1024))
Dim o : Set o = (New Test)(Array("Hello World", 1024))
Bit of a pain though.
You can work around it by having your Init function returning the object itself...
Class Test
Private m_s
Public Function Init(s)
m_s = s
Set Init = Me
End Function
Public Function Hello()
Hello = m_s
End Function
End Class
Dim o
Set o = (New Test).Init("hello world")
Echo o.Hello
You have to do it in two steps. VB Script doesn't support overloading so you can't modify the default constructor with new parameters. Same goes for Vb6
A bit hackish, for sure, but when I need varargs in calls, one of my parameters I pass in as an array, i.e.
Rem printf done poorly
sub printf(fmt, args)
dim fp, vap:
dim outs:
dim fini:
fini = 0:
vap = 0:
while (not fini)
fp = index(fmt,"%"):
if (not(isNull(fp))) then
' do something with %f, %s
select case(fp)
case 'c':
outs = outs & charparse(args(vap)):
case 's':
outs = outs & args(vap):
' and so on. Quite incomplete but you get the idea.
end select
vap = vap + 1
end if
wend
end sub
printf("%s %d\n",array("Hello World", 42)):

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