start
步骤一：新建类库项目，新建FirstControl.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

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

namespace UcDll
{
    public class FirstControl : Control
    {

        public FirstControl()
        {

        }

        // ContentAlignment is an enumeration defined in the System.Drawing
        // namespace that specifies the alignment of content on a drawing 
        // surface.
        private ContentAlignment alignmentValue = ContentAlignment.MiddleLeft;

        [
        Category("Alignment"),
        Description("Specifies the alignment of text.")
        ]
        public ContentAlignment TextAlignment
        {

            get
            {
                return alignmentValue;
            }
            set
            {
                alignmentValue = value;

                // The Invalidate method invokes the OnPaint method described 
                // in step 3.
                Invalidate();
            }
        }


        protected override void OnPaint(PaintEventArgs e)
        {
            base.OnPaint(e);
            StringFormat style = new StringFormat();
            style.Alignment = StringAlignment.Near;
            switch (alignmentValue)
            {
                case ContentAlignment.MiddleLeft:
                    style.Alignment = StringAlignment.Near;
                    break;
                case ContentAlignment.MiddleRight:
                    style.Alignment = StringAlignment.Far;
                    break;
                case ContentAlignment.MiddleCenter:
                    style.Alignment = StringAlignment.Center;
                    break;
            }

            // Call the DrawString method of the System.Drawing class to write   
            // text. Text and ClientRectangle are properties inherited from
            // Control.
            e.Graphics.DrawString(
                Text,
                Font,
                new SolidBrush(ForeColor),
                ClientRectangle, style);

        }
    }
}

步骤二：编译，添加项目引用即可。
这里的重点是控件界面也要由自己绘。
url:http://greatverve.cnblogs.com/archive/2012/04/27/control-Inherit.html
参考：
http://www.cnblogs.com/guanjinke/category/77694.html
http://blog.csdn.net/yysyangyangyangshan/article/details/7078471
凡事以大气象去面对，优秀是一种习惯。