How to get or Kill all instances from certain class?

How can I get all instances from a certain class or kill all instances of certain class?

For Example, I've a Class MyClass which I intantiate three times as m1, m2 and m3.

开发者_开发技巧

Is there a way to get or kill all these instances?

more clarification : when I've a "settings form" class. When the user click Settings button the application makes instance from this class. When he clicks the same button again it makes new instance. I want it show the 1st instance only and not making new instance

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Not that i'm aware, but you can save the instance when constructing the object on some sort of collection so you can access all instances later:

public class MyClass {
    public static List<MyClass> instances = new List<MyClass>();
    public MyClass() {
        instances.Add(this);
    }
}

EDIT:

Save the settings class as a field for the form, and when clicking button, check if that field is null; if so, instantiate

public class Form1 : Form {
    private SettingsClass settings;

    ...
    ...

    private void btnSettings_Click(object sender, EventArgs e) {
        if (settings == null) {
            settings = new SettingsClass();
        } else {
            // do nothing, already exists
        }

        // use settings object
    }
}

---

For your form example, you can keep the form as a variable in your main program. This way you only have one instance of the settings form.

private SettingsForm settingsForm = null;

SettingsButton_Click()
{
    if(settingsForm == null)
    {
         settingsForm = new SettingsForm();
    }
    settingsForm.Show();
}

---

When you instantiate them, put them into a higher-scoped generic list:

List<MyClass> myObjects = new List<NyClass>();

Then, when you make the objects inside a function:

m1 = new MyClass();
m2 = new MyClass();
m3 = new MyClass();

myObjects.add(m1);
myObjects.add(m2);
myObjects.add(m3);

then, at a later stage:

foreach(MyClass m in myObjects)
{
    m.do_whatever_you_want();
    m = null; // SEE EDIT BELOW
}

--------Edit----------- As discussed with John Saunders in the comments below, this is not possible. My apologies.