Update Element in ArrayList Structure

[wg]

I have worked on this for a while and have not been able to get it working.
I seem to be missing something. What I am attempting to do is get
information from a csv file such as: name (stirng), unit number (int),
address (int), value (int), etc. I created a structre to handle each
element. Since there is an unknown number of rows I have used an arraylist
to hold it. This works using the arraylist.add(structure).

The problem is that after loading I get information from an external device
tied to the serial port. As this information is recieved I would like to
update the value element in the arraylist. I did this in VB6 by using a UDT
the dynamic arrays. I have read that this should not be done in VB.NET, to
use the arraylist instead.


Any help would be greatly appriciated.

Thanks

wg

 

[Tom Shelton]

I have worked on this for a while and have not been able to get it working.
I seem to be missing something. What I am attempting to do is get
information from a csv file such as: name (stirng), unit number (int),
address (int), value (int), etc. I created a structre to handle each
element. Since there is an unknown number of rows I have used an arraylist
to hold it. This works using the arraylist.add(structure).

The problem is that after loading I get information from an external device
tied to the serial port. As this information is recieved I would like to
update the value element in the arraylist. I did this in VB6 by using a UDT
the dynamic arrays. I have read that this should not be done in VB.NET, to
use the arraylist instead.


Any help would be greatly appriciated.

Thanks

wg

wg... use a class in an arraylist. Using a structure can be made to
work, but it is very inefficent.

 

[Ken Tucker [MVP]]

Hi,

Directcast(arraylist.item(number), YourStructureName).value = NewValue

Ken
-----------------
I have worked on this for a while and have not been able to get it working.
I seem to be missing something. What I am attempting to do is get
information from a csv file such as: name (stirng), unit number (int),
address (int), value (int), etc. I created a structre to handle each
element. Since there is an unknown number of rows I have used an arraylist
to hold it. This works using the arraylist.add(structure).

The problem is that after loading I get information from an external device
tied to the serial port. As this information is recieved I would like to
update the value element in the arraylist. I did this in VB6 by using a UDT
the dynamic arrays. I have read that this should not be done in VB.NET, to
use the arraylist instead.


Any help would be greatly appriciated.

Thanks

wg

 

[Cor Ligthert]

WG,

You know that with OleDb you can in one time from a CSV make a dataset?

See this sample on our site
http://www.windowsformsdatagridhelp.info/default.aspx?ID=1b644f6b-aa01-49f6-bc1f-212f9e0de193

I hope this helps,

Cor

 

[Armin Zingler]

I have worked on this for a while and have not been able to get it
working. I seem to be missing something. What I am attempting to do
is get information from a csv file such as: name (stirng), unit
number (int), address (int), value (int), etc. I created a structre
to handle each element. Since there is an unknown number of rows I
have used an arraylist to hold it. This works using the
arraylist.add(structure).

The problem is that after loading I get information from an external
device tied to the serial port. As this information is recieved I
would like to update the value element in the arraylist. I did this
in VB6 by using a UDT the dynamic arrays. I have read that this
should not be done in VB.NET, to use the arraylist instead.

Value types added to an arraylist can not be changed. Retrieving the Item
always retruns a copy because it's a value type. As Tom wrote, use a class
instead.

Armin

 

[Armin Zingler]

Directcast(arraylist.item(number), YourStructureName).value =
NewValue

Doesn't work because the returned value is a value type.

Armin

 

[Herfried K. Wagner [MVP]]

Doesn't work because the returned value is a value type.

You'll have to reassign the value to the item after changingt the copy, or
use a class instead of the structure ;-).

 

[wg]

I have attempted to use a class in the beginning but could never get it to
work right. Could someone give a quick example?


Thanks

wg

 

[Guest]

Thanks for the tip Cor. I assume the row delimiter is a \ or can be anything
that the FMT=Delimited* is set to like the *. Is this correct?