今天玩了玩C/S开发，也随便练习了很久不用的委托

父窗体中写的代码

#region 委托与事件传递

    public delegate void TextChangedHandler(string s);

    public class CallObject {

        //用来存放子窗体返回的结果        public string ResultValue = "";        //定义事件对象 可以让子窗体修改父窗体的状态        public event TextChangedHandler SelTextChanged;        //以调用delegate的方式触发函数        public void ChangeSelText(string s)        {             if (SelTextChanged != null)            {                 //调用delegate                SelTextChanged(s);            }        }    }    #endregion

   void co_SelTextChanged(string s)

        {             textBox2.Text = s;        }        private void button3_Click(object sender, EventArgs e)        {             CallObject co = new CallObject();            co.SelTextChanged += new TextChangedHandler(co_SelTextChanged);            Form3 f3 = new Form3(co);            f3.ShowDialog();            textBox2.Text = "测试结果" + co.ResultValue;        }

子窗体中写的代码

public Form3(CallObject cov) : this() { this.co = cov; }

        private void button1_Click(object sender, EventArgs e)        {             co.ResultValue = textBox1.Text;            Close();        }

        private void radioButton1_CheckedChanged(object sender, EventArgs e)

        {             co.ChangeSelText("A");        }  

        private void radioButton2_CheckedChanged_1(object sender, EventArgs e)

        {             co.ChangeSelText("B");        }

        private void radioButton3_CheckedChanged(object sender, EventArgs e)

        {             co.ChangeSelText("C");        }

结果