Moving data to & from form/class

[Blip]

I am still struggling with a pattern that can be used to move data
from a class to a related form, and from the class method results to
text boxes, listboxes, etc on the form. I usually get it working by
adding enough contructors and instances (but I'm sure that I don't
always point at the form or class instant that I am expecting).

This is frustrating because it should be so simple. BTW, I tried
putting:

Tester t = new Tester(); on the form1 load event, and
Form1 f = new Form1(); at the top of the class the class.

This resulted in an infinite loop. I hope that this code describes my
issue, but if it dowsn't please let me know what you want to see.
Thanks very much for taking some time with this.


tester.cs:

using System;
using System.Collecti ons.Generic;
using System.Text;
using System.Windows. Forms;

namespace Test
{
public class Tester
{

public int total;

public void Foo()
{
string b = "bar"
}

public void Bar() {
{
int i = 0;

int j = 0;
int k = 0;
int m = 0;
int n = 0;
int p = 0;

for (i=0;i<entries< i++)
int sum1 = j + k;
sum2 = m+n+p;
total = sum1 + sum2;
}



Here is the form1.cs

using System;
using System.Collecti ons.Generic;
using System.Text;
using System.Windows. Forms;

namespace Test

public partial class Form1 : Form
{
public Tester t = new Tester();
public Form1()
{
InitializeCompo nent();
}

private void buttonBegin_Cli ck(object sender, EventArgs e)
{
listBox1.Items. Add(t.b);
}

private void PopulateListBox Fields (string message)
{
listBox1.Items. Add(t.total);
}
}
}

[Peter Duniho]

Re: Moving data to &amp; from form/class

On Sat, 15 Dec 2007 17:43:27 -0800, Blip <blip@krumpli.c omwrote:

I am still struggling with a pattern that can be used to move data
from a class to a related form, and from the class method results to
text boxes, listboxes, etc on the form.

The exact pattern will depend on your specific needs in a particular
situation. However, the basic idea is always the same: instantiate the
objects as is appropriate for the lifetime of the object, not specifically
for the purpose of exposing one object to another. Then, make a different
(but possibly related) design choice regarding exposing one object to
another.

Usually this latter step involves passing a reference for the instance of
one class to the instance of another. Occasionally, some other mechanism
will be used, such as a singleton or some sort of static variable or
collection.

What's correct just depends on your specific situation.

I usually get it working by
adding enough contructors and instances (but I'm sure that I don't
always point at the form or class instant that I am expecting).

IMHO, you should go about it in a more directed way. A sure path to
terrible, buggy, difficult-to-maintain code is to just add stuff until it
works. You should get out of that habit asap.

This is frustrating because it should be so simple. BTW, I tried
putting:
>
Tester t = new Tester(); on the form1 load event, and
Form1 f = new Form1(); at the top of the class the class.
>
This resulted in an infinite loop.

Yes, of course it would. Fortunately in that case, "adding enough
constructors and instances" just blew up. But it's a good demonstration
of why a more directed approach is better.

I hope that this code describes my
issue, but if it dowsn't please let me know what you want to see.

Well, the one thing I don't understand in the code you posted is what
exactly you're trying to show. I would say that the biggest issue is that
your Form1 class tries to reference a non-existent member "b" of the
Tester class. You've got a "b" in the Tester class, but it's a local
variable. It would have to be a public field or property for Form1 to get
at it.

Other than that problem I would think that the code would work fine as
written (not counting missing braces and whatnot, which I'll assume is
just a mistake that happened when posting the code).

Maybe you can be more specific about what in the code you posted isn't
working, and how you'd like it to work.

Pete