ARRAYLIST ADDING A CLASS

[blisspikle]

The following sub form1_load reads in a text file that will say
something like the text below. I think that the problem is that every
time I add a class V_Sensor into the arraylist it puts it in as a
reference. So in the end all of the arraylist items turn out to be the
same as the last sensor in the text file. I am new and I do not know
how to declare and put a class into an arraylist so it will be a
different reference for every loop.


<text>
NAME=SENSOR1
SLOPE=1.1
YINTERCEPT=1.2
NAME=SENSOR2
SLOPE=2.1
YINTERCEPT=2.2
etc....
</text>

<code>
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles MyBase.Load
Dim V_Sensor As New AnalogSensor()
Dim V_FileReader As StreamReader
Dim V_TextLine As String
Dim V_TextSplit(2) As String
Const V_FileName As String = "HDTCHECKFIX.ini"
V_FileReader = File.OpenText(V_FileName)
V_TextLine = V_FileReader.ReadLine
Do While Not V_TextLine = ""
V_TextSplit = V_TextLine.Split("=")
If V_TextSplit(0).ToUpper = "NAME" Then
If Not V_Sensor.Name = "" Then
AnalogSensors.Add(V_Sensor)
End If
V_Sensor.Name = ""
V_Sensor.Name = V_TextSplit(1)
End If
If V_TextSplit(0).ToUpper = "SLOPE" Then
V_Sensor.Slope = V_TextSplit(1)
End If
If V_TextSplit(0).ToUpper = "YINTERCEPT" Then
V_Sensor.YIntercept = V_TextSplit(1)
End If
V_TextLine = V_FileReader.ReadLine
Loop
If Not V_Sensor.Name = "" Then
AnalogSensors.Add(V_Sensor)
End If
V_Sensor.Name = ""
V_FileReader.Close()
End Sub
</code>

Thank you,

 

[Guest]

If I read you code correctly, you are declaring V_Sensor as a new instance of
AnalogSensor before your loop then in your loop, you are using
AnalogSensor.Add(V_Sensor). I don't know what your AnalogSensor class is but
this doesn't make any sense! Why would you add an analogsensor to itself?
What you might have in mind is:

Dim myArrayList as New ArrayList

Start loop
Dim v_Sensor as new AnalogSensor
......
.....
MyArrayList.Add(v_Sensor)
end loop

 

[blisspikle]

Sorry. I guess that I forgot to mention that the "ANALOGSENSORS" that
was used throughout the code is a public arraylist. The code below
seems to be working quite well after I messed with it. The part that
is different is in the arraylist using ANALOGSENSORS.ADD(NEW
ANALOGSENSOR()). I did not (still do not?) know how to create another
instance of the analogsensor class for each do loop when the name in
the text file changes.


<code>
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles MyBase.Load
Dim V_Sensor As New AnalogSensor()
Dim V_FileReader As StreamReader
Dim V_TextLine As String
Dim V_TextSplit(2) As String
Const V_FileName As String = "HDTCHECKFIX.ini"
V_FileReader = File.OpenText(V_FileName)
V_TextLine = V_FileReader.ReadLine
Do While Not V_TextLine = ""
V_TextSplit = V_TextLine.Split("=")
If V_TextSplit(0).ToUpper = "NAME" Then
AnalogSensors.Add(New AnalogSensor())
V_Sensor = AnalogSensors(AnalogSensors.Count - 1)
End If
If V_TextSplit(0).ToUpper = "SLOPE" Then
V_Sensor.Slope = V_TextSplit(1)
End If
If V_TextSplit(0).ToUpper = "YINTERCEPT" Then
V_Sensor.YIntercept = V_TextSplit(1)
End If
V_TextLine = V_FileReader.ReadLine
Loop
V_FileReader.Close()

End Sub

Public Class AnalogSensor
Public Name As String
Public Slope As Decimal
Public Sub New()
End Sub
End Class
</code>


I guess the way I with that it would work is ....

dim myclass1 as new class
dim myarraylist1 as new arraylist
for i = 0 to 100
myclass1 = new class
myarraylist1(i).add(myclass1)
myclass1.name = "bill " & i
next

My understanding is not very good yet.

 

[Michael C#]

Based on what you have, it appears that your file might look something like
this:

NAME=SENSOR1
SLOPE=0.75
YINTERCEPT=12
....

Another option, that won't force you to implicitly cast your V_Sensor to an
Object (when you add it to the ArrayList) and then back to a V_Sensor
immediately is to use a counter. This works if:

1) Every V_Sensor in your file is guaranteed to have all three entries,
2) NAME is guaranteed to be first every time

Also note the .Split() line - I added ", 2" to it so that it will return a
maximum of two items when is splits your string.

Dim V_FileReader As StreamReader
Dim V_TextLine As String
Dim V_TextSplit(2) As String
Const V_FileName As String = "HDTCHECKFIX.ini"
V_FileReader = File.OpenText(V_FileName)
V_TextLine = V_FileReader.ReadLine
Dim V_Sensor As New AnalogSensor
Dim AnalogSensors As New ArrayList
Dim Counter As Integer = 0
Do While Not V_TextLine = ""
V_TextSplit = V_TextLine.Split("=", 2)
' Initialize the counter to 1 when we read in the Name
If V_TextSplit(0).ToUpper = "NAME" Then
V_Sensor = New AnalogSensor
V_Sensor.Name = V_TextSplit(1)
Counter = 1
End If
' Increment the counter by one.
If V_TextSplit(0).ToUpper = "SLOPE" Then
V_Sensor.Slope = Convert.ToDecimal(V_TextSplit(1))
Counter += 1
End If
' Increment the counter by one. We explicitly convert the
number to
' decimal here.
If V_TextSplit(0).ToUpper = "YINTERCEPT" Then
V_Sensor.YIntercept = Convert.ToDecimal(V_TextSplit(1))
Counter += 1
End If
' We only add the sensor after the third item is read
If (Counter = 3) Then
Counter = 0
AnalogSensors.Add(V_Sensor)
End If
V_TextLine = V_FileReader.ReadLine
Loop
V_FileReader.Close()

 

[Cor Ligthert]

Blispikle,

You cannot set a class in an arraylist. You can set an instanced object in
an arraylist.
And because you do that now do that only one time, are you placing all the
time the same object in your arraylist.

As advice, forget to instance datafields in the top of your program. That is
from the Cobol time.

Just do (in psuedo code)
do while reading
Dim V_Sensor As New AnalogSensor
V_Sensoer.whatever = mydata
myArraylist.Add(V_Sensoer)
readnextone
loop

Now all those objects are made and not deleted because you have set a
reference to it from the arraylist.

And please don't use uppercases. That is called screaming in newsgroups.

I hope this helps,

Cor