窗体之间调用方法，参数等。（传窗体引用）

其实就是传 this

窗体A：

public partial class FormA : Form
    {
        public FormA()
        {
            InitializeComponent();
        }

        public void AAA()
        {
            MessageBox.Show("来自A窗体的方法");
        }

        private void button1_Click(object sender, EventArgs e)
        {
            FormB bFrm = new FormB(this);
            bFrm.Show();
        }
    }

窗体B：

 public partial class FormB : Form
    {
        FormA aFrm;
        public FormB(FormA frm)
        {
            InitializeComponent();
            this.aFrm = frm;
        }

        private void button1_Click(object sender, EventArgs e)
        {
            this.aFrm.AAA();
        }
    }