学步园

1.form2传值给form1
form1
  textbox1, button1

form2
  button1

form1:
 private void button1_Click(object sender, EventArgs e)
        {
            value.Form2 form2 = new value.Form2();
            form2.ReturnValue = new value.Form2.returnvalue(showvalue);
            form2.ShowDialog();//
            form2.Show();
        }

        private void showvalue( int i)
        {
            this.textBox1.Text = i.ToString();
        }

form2:
  public delegate void returnvalue(int i);
        public returnvalue ReturnValue;
  private void button1_Click(object sender, EventArgs e)
        {
            if (ReturnValue != null)
            {
                ReturnValue(99);
            }

        }

2.form1传值给form2

form1
button1

form2
button1,textbox1

form1:
 private void button1_Click(object sender, EventArgs e)
        {

             value.Form2 form2 = new value.Form2("hello!");
            form2.Show();
        }

form2:
  public Form2(string str)
        {
            InitializeComponent();
            this.textBox1.Text = str;
        }

3.form1与form2之间的双向传值
(form1与form2可同时改变静态变量的值)
form1：
public static string str = "hello!";

form2：
 private void button1_Click(object sender, EventArgs e)
        {
 
            this.textBox1.Text = Form1.str;
        }