您可以定义要在Form2中返回并在Form1中访问它们的公共变量:

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
}

在Form1中:

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