2 个UserControl 的传值问题

问题描述：有2个UserControl：UserControl1 里有一个Button，UserControl2 里面有一个TextBox，这2个控件都加载到了主窗体Form1 上。要求的是，点击 UserControl1 的button 显示 UserControl2中TextBox输入的内容。

一般来讲有2种方式：

1. 公开属性

2. 声明事件

来看看这2种方式的操作代码：

1. 公开2个UserControl的属性。并在Form1中使用

public partial class UserControl1 : UserControl
    {
        public UserControl1()
        {
            InitializeComponent();

        }

        public Button Btn // Define Btn as public
        {
            get
            {
                return this.button1;
            }
        }
    }

UserControl1

 public partial class UserControl2 : UserControl
    {
        public UserControl2()
        {
            InitializeComponent();
        }

        public TextBox textbox  // define textbox as public
        {
            get
            { return this.textBox1; }
        }
    }

UserControl2

在From1中注册Button的事件

 public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            this.userControl11.Btn.Click += new EventHandler(Btn_Click);
        }

        void Btn_Click(object sender, EventArgs e)
        {
            MessageBox.Show(this.userControl21.textbox.Text);
        }
}

注册Button事件

2. 声明事件

public partial class UserControl1 : UserControl
    {
        public UserControl1()
        {
            InitializeComponent();

        }
        public event EventHandler BtnClick; //define one public Click event.

        private void button1_Click(object sender, EventArgs e)
        {
            BtnClick(sender, e); // just do it.
        }
    }

UserControl1

 public partial class UserControl2 : UserControl
    {
        public UserControl2()
        {
            InitializeComponent();
        }

        public event Action<string> GetText; //define one action to get textbox's  text value

        private void textBox1_TextChanged(object sender, EventArgs e)
        {
            GetText(textBox1.Text); // Get this text after input.
        }
    }

UserControl2

在Form1中调用

 public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            this.userControl21.GetText += new Action<string>(userControl21_GetText); // register gettext event.
            this.userControl11.BtnClick += new EventHandler(userControl11_Click); // Register Click event.
        }
        string text = null;
        void userControl11_Click(object sender, EventArgs e)  // implement it
        {
            MessageBox.Show(text);
        }

        void userControl21_GetText(string obj) // implement it.
        {
            text = obj;
        }
}