Changing TopMost of a form from another form

Question

I'm trying to change the topmost of my Main form from the Settings form and it doesnt work. Here is the code:

private void button1_Click(object sender, EventArgs e)
        {
            if (this.button1.Text == "Top Most: ON")
            {
                this.button1.Text = "Top Most: OFF";

                var main = new Main();
                main.TopMost = false;
            }

            else if (this.button1.Text == "Top Most: OFF")
            {
                this.button1.Text = "Top Most: ON";

                var main = new Main();
                main.TopMost = true;
            }
        }

Answer 1

In the settings form:

private MainForm _mf;

public SettingsForm(MainForm mf){
    InitializeComponent();
    _mf = mf;
}


private void button1_Click(object sender, EventArgs e)
{
    _mf.TopMost = !_mf.TopMost;
    this.button1.Text == "Top Most: " + _mf.TopMost ? "ON" : "OFF;
}

And in your main form that shows the settings:

new SettingsForm(this).Show...