Class accessing form objects

[SamIAm]

Hi

I have a form named form1. I have a class called class1. I want to call a
recursive method in class1 called MyMethod()

I would like log info to a listbox, listbox1, on the form as MyMethod
performs its recursion. How do I pass an instance into class1 so that it can
add items to the listbox?

Should be easy I guess.

S

 

[Christian Schwendtner (CS)]

Hi

I have a form named form1. I have a class called class1. I want to call a
recursive method in class1 called MyMethod()

I would like log info to a listbox, listbox1, on the form as MyMethod
performs its recursion. How do I pass an instance into class1 so that it can
add items to the listbox?

Should be easy I guess.

S

Hi.

public class class1 {
public void MyMethod(ListBox listBox) {
...
}
}

or you pass the ListBox to the constructor of class1.

hth,
Chris

 

[Simon Trew]

I would prefer to make the reference to the list box a member variable, and
not pass it at each recursion, which is wasteful on the stack:

public class class1 {
{
private ListBox listBoxForLogging;

public void MyMethod(ListBox listBoxForLogging)
{
this.listBoxForLogging = listBoxForLogging;
MyRecursiveMethod(1);
}

private Log(string message)
{
ListBoxForLogging.Items.Add(message);
}

private void MyRecursiveMethod(int depth) // trivial example
{
Log("depth = " + depth.ToString());
if (depth < 10)
{
MyRecursiveMethod(depth + 1);
}
}
}

This is a typical pattern for recursion, with a public "shell" method that
performs some initialisation and calls a private method that actually does
the recursion. Not sure if this pattern has a common name. In Pascal, which
allows procedures to be nested, it is common to define the private recursing
method *inside* the public shell method; the inner method gets access to the
shell method's variables because of the scoping rules.

S.

 

[SamIAm]

Thanks for the replies

I would prefer to make the reference to the list box a member variable, and
not pass it at each recursion, which is wasteful on the stack:

public class class1 {
{
private ListBox listBoxForLogging;

public void MyMethod(ListBox listBoxForLogging)
{
this.listBoxForLogging = listBoxForLogging;
MyRecursiveMethod(1);
}

private Log(string message)
{
ListBoxForLogging.Items.Add(message);
}

private void MyRecursiveMethod(int depth) // trivial example
{
Log("depth = " + depth.ToString());
if (depth < 10)
{
MyRecursiveMethod(depth + 1);
}
}
}

This is a typical pattern for recursion, with a public "shell" method that
performs some initialisation and calls a private method that actually does
the recursion. Not sure if this pattern has a common name. In Pascal, which
allows procedures to be nested, it is common to define the private recursing
method *inside* the public shell method; the inner method gets access to the
shell method's variables because of the scoping rules.

S.

call it