做过asp.net的人都知道开发的时候使用用户控件很方便，为功能模块化提供了相当大的灵活性。开发Windows窗体也可以使用用户控件，这里我们来看看为用户控件添加属性和事件，并实现把消息发送到父容器。  

         用户控件的实现比较简单，直接从System.Windows.Forms.UserControl。  

public class UserControl1 : System.Windows.Forms.UserControl  

为了便于测试我在上面添加了一个TextBox,并注册TextBox的TextChanged事件，  

this.textBox1.TextChanged += new System.EventHandler(this.textBox1_TextChanged);  

事件处理函数，  

private void textBox1_TextChanged(object sender, System.EventArgs e)  

{  

     MessageBox.Show(this.textBox1.Text);  

}  

这里演示如果控件中文本框的内容改变就会用MessageBox显示当前的文本框内容。  

控件显示如下：  

在窗体中添加上面的用户控件，当我们改变textBox的文本时，可以看到跳出一个对话框，很简单吧。

 下面来看看对控件添加属性。
这里定义一个私有变量。  

private string customValue;  

添加访问他的属性  

public string CustomValue  

{  

     get{return customValue;}  

     set{customValue =value;}  

}  

在窗体中使用的时候像普通控件一样进行访问，  

userControl11.CustomValue = "用户控件自定义数据";  

通过事件可以传递消息到窗体上，在定义之前我们先来写一个简单的参数类。  

public class TextChangeEventArgs : EventArgs
{
	private string message;
	public TextChangeEventArgs(string message)
	{
		this.message = message;
	}
public string Message
	{
		get{return message;}
	}
}

定义委托为，  

public delegate void TextBoxChangedHandle(object sender,TextChangeEventArgs e);

 接下去在用户控件中添加事件， 

//定义事件 

public event TextBoxChangedHandle UserControlValueChanged;  

为了激发用户控件的新增事件，修改了一下代码，  

private void textBox1_TextChanged(object sender, System.EventArgs e)  

{  

     if(UserControlValueChanged != null)  

         UserControlValueChanged(this,new TextChangeEventArgs(this.textBox1.Text));  

} 

好了，为了便于在Csdn上回答问题，把完整的代码贴了出来：  

using System;
using System.Collections;
using System.ComponentModel;
using System.Drawing;
using System.Data;
using System.Windows.Forms;

namespace ZZ.WindowsApplication1
{
	public class UserControl1 : System.Windows.Forms.UserControl
	{
		private System.Windows.Forms.TextBox textBox1;
		private string customValue;
		
private System.ComponentModel.Container components = null;

		public string CustomValue
		{
			get{return customValue;}
			set{customValue =value;}
		}

		//定义事件
		public event TextBoxChangedHandle UserControlValueChanged;

		public UserControl1()
		{
			InitializeComponent();
		}

		protected override void Dispose( bool disposing )
		{
			if( disposing )
			{
				if(components != null)
				{
					components.Dispose();
				}
			}
			base.Dispose( disposing );
		}

		#region 组件设计器生成的代码
		private void InitializeComponent()
		{
			this.textBox1 = new System.Windows.Forms.TextBox();
			this.SuspendLayout();
			this.textBox1.Location = new System.Drawing.Point(12, 36);
			this.textBox1.Name = "textBox1";
			this.textBox1.TabIndex = 0;
			this.textBox1.Text = "textBox1";
			this.textBox1.TextChanged += new System.EventHandler(this.textBox1_TextChanged);
			this.Controls.Add(this.textBox1);
			this.Name = "UserControl1";
			this.Size = new System.Drawing.Size(150, 92);
			this.ResumeLayout(false);

		}
		#endregion

		private void textBox1_TextChanged(object sender, System.EventArgs e)
		{
			if(UserControlValueChanged != null)
				UserControlValueChanged(this,new TextChangeEventArgs(this.textBox1.Text));
			
		}
	}
	//定义委托
	public delegate void TextBoxChangedHandle(object sender,TextChangeEventArgs e);

	public class TextChangeEventArgs : EventArgs
	{
		private string message;
		public TextChangeEventArgs(string message)
		{
			this.message = message;
		}
		public string Message
		{
			get{return message;}
		}
	}
}

 使用时要在窗体中注册上面的事件，比较简单都贴源代码了，  

using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;

namespace ZZ.WindowsApplication1
{
	public class Form1 : System.Windows.Forms.Form
	{
		private WindowsApplication1.UserControl1 userControl11;
		private System.ComponentModel.Container components = null;

		public Form1()
		{
			InitializeComponent();
			userControl11.CustomValue = "用户控件自定义数据";
			userControl11.UserControlValueChanged += new TextBoxChangedHandle(userControl11_UserControlValueChanged);
		}

		protected override void Dispose( bool disposing )
		{
			if( disposing )
			{
				if (components != null) 
				{
					components.Dispose();
				}
			}
			base.Dispose( disposing );
		}

		#region Windows 窗体设计器生成的代码
		private void InitializeComponent()
		{
			this.userControl11 = new WindowsApplication1.UserControl1();
			this.SuspendLayout();
			this.userControl11.Location = new System.Drawing.Point(8, 8);
			this.userControl11.Name = "userControl11";
			this.userControl11.Size = new System.Drawing.Size(150, 84);
			this.userControl11.TabIndex = 0;
			this.AutoScaleBaseSize = new System.Drawing.Size(6, 14);
			this.ClientSize = new System.Drawing.Size(292, 193);
			this.Controls.Add(this.userControl11);
			this.Name = "Form1";
			this.Text = "Form1";
			this.ResumeLayout(false);

		}
		#endregion

		 [STAThread]
		static void Main() 
		{
			Application.Run(new Form1());
		}

		private void userControl11_UserControlValueChanged(object sender, TextChangeEventArgs e)
		{
			MessageBox.Show("当前控件的值为:" + e.Message);
		}
	}
}

 另外需要动态加载，就把控件添加在容器的Controls集合就行了，下面是在构造函数中添加控件， 

public Form1()
{
	InitializeComponent();
	UserControl1 uc = new UserControl1();
	uc.CustomValue = "动态加载的用户控件";
	uc.UserControlValueChanged += new TextBoxChangedHandle(userControl11_UserControlValueChanged);
	this.Controls.Add(uc);
}

另外从VS.net中的工具箱中拖动用户控件到窗体上，如果是第一次需要编译一下项目。