How to open new form, pass parameter and return parameter back

Question

In my application i open new form:

private void button1_Click(object sender, EventArgs e)
{
    Form2 = new Form2 ("bla bla");
    Form2 .ShowDialog();
}

This is my form that i am opening and want to pass back parameter:

public partial class Form2: Form
{
    public Form2 (string file)
    {
        InitializeComponent();
    }
}

Answer 1

You can define public variables which want to return in Form2 and access them in Form1:

public partial class Form2: Form
{
    public int x;    //can be private too
    public string y; //can be private too

    public Form2 (string file)
    {
        InitializeComponent();
    }

    //define some function which changes defined global values
}

In Form1:

Form2 form2 = new Form2("bla bla");
form2.ShowDialog();
MessageBox.Show(form2.x.ToString());
MessageBox.Show(form2.y);