用委托实现窗体间传值

1. 新建一个工程.在Form1中添加一个Label和一个Button.新建一个事件类,让它有一个string 类型的属性,用于传值.

    1 ///ReturnValueEventArgs.cs
    2 using System;
    3 using System.Collections.Generic;
    4 using System.Text;
    5 
    6 namespace test
    7 {
    8     public  class ReturnValueEventArgs:EventArgs 
    9     {
   10         private string str;
   11 
   12         public string strMessage
   13         {
   14             get
   15             {
   16                 return str;
   17             }
   18             set
   19             {
   20                 str = value;
   21             }
   22         }
   23     }
   24 }
   25 

2.  新建一个窗体Form2.添加一个TextBox和一个Button.添加如下代码.

    1 using System;
    2 using System.Collections.Generic;
    3 using System.ComponentModel;
    4 using System.Data;
    5 using System.Drawing;
    6 using System.Text;
    7 using System.Windows.Forms;
    8 
    9 namespace test
   10 {
   11     public partial class Form2 : Form
   12     {
   13         public  event returnValueHandler returnValue;
   14 
   15         public Form2()
   16         {
   17             InitializeComponent();
   18         }
   19 
   20         private void button1_Click(object sender, EventArgs e)
   21         {
   22             ReturnValueEventArgs ee = new ReturnValueEventArgs();
   23             ee.strMessage = textBox1.Text;
   24             returnValue(sender, ee);
   25         }
   26     }
   27 }

3. 在Form1中添加如下代码.

    1 using System;
    2 using System.Collections.Generic;
    3 using System.ComponentModel;
    4 using System.Data;
    5 using System.Drawing;
    6 using System.Text;
    7 using System.Windows.Forms;
    8 
    9 
   10 namespace test
   11 {
   12     public delegate void  returnValueHandler (object sender ,ReturnValueEventArgs e);
   13     public partial class Form1 : Form
   14     {
   15         
   16         public Form1()
   17         {
   18             InitializeComponent();
   19         }
   20 
   21         private void button1_Click(object sender, EventArgs e)
   22         {
   23             Form2 frm = new Form2();
   24             frm.Show();
   25             frm.returnValue += new returnValueHandler(frm_returnValue);
   26             
   27 
   28         }
   29 
   30         void frm_returnValue(object sender, ReturnValueEventArgs e)
   31         {
   32 
   33             label1.Text = e.strMessage;
   34             //throw new Exception("The method or operation is not implemented.");
   35         }
   36     }
   37 }

这样就可以实现窗体之间通过委托传值.