写了个继承picturebox的控件，出问题了

Question

using System;
using System.ComponentModel;
using System.Collections.Generic;
using System.Diagnostics;
using System.Text;
using System.Drawing;
using System.Windows.Forms;namespace WindowsControlLibrary1
{
    public enum PictureSource
    {
        Path,       //本地路径
        DataSoure,   //数据库
        resx,        //资源文件
        NetWrok,    //局域网
        WWW         //广域网
    }
    
    public partial class F2PictureBox : PictureBox
    {
        private PictureSource pictureSource;
        private string picturePath = "";             //问题在这里＝＝＝＝＝＝＝＝＝＝＝＝＝＝
        private bool isDataBind = false;
        private int idValue;
        private bool isCommit = false;
        private string commitFieldName = "";
        private string disFieldName = "";
        private string relatFieldName = "";
        private Image f2Image;        public F2PictureBox()
        {
            InitializeComponent();
        }        public F2PictureBox(IContainer container)
        {
            container.Add(this);            InitializeComponent();
        }        /// <summary>
        /// 引用图片类型
        /// </summary>
        [Category("F2")]
        [DefaultValue("")]
        [Description("引用图片类型，Path：本地路径；DataSoure：数据库；resx：资源文件；NetWrok：局域网；WWW：广域网")]
        public PictureSource F2PictureSource
        {
            get { return pictureSource; }
            set { pictureSource = value; }
        }        /// <summary>
        /// 图片来源路径
        /// </summary>
        [Category("F2")]
        [DefaultValue("")]
        [Description("图片来源路径")]
        public string F2Path
        {
            get { return picturePath; }
            set { picturePath = value; }
        }        /// <summary>
        /// 获取图片资源
        /// </summary>
        [Category("F2")]
        [DefaultValue("")]
        [Description("获取图片资源")]
        public Image F2Image
        {
            get
            {
                return f2Image;
            }
            set
            {
                switch (pictureSource)
                {
                    case PictureSource.Path:
                        string ext = picturePath.Trim();
                        string s = ext;
                        if (ext.Length > 4)
                        {
                            ext = ext.Substring(ext.Length - 3).ToUpper(); ;
                            if (ext == "BMP")
                            {
                                MessageBox.Show("BMP");
                                Bitmap bmp = new Bitmap(s);
                                this.f2Image = (Image)bmp;
                                this.Image = f2Image;
                            }
                        }
                        this.Refresh();
                        break;
                    case PictureSource.DataSoure:
                        break;
                    case PictureSource.resx:
                        break;
                    case PictureSource.NetWrok:
                        break;
                    case PictureSource.WWW:
                        break;
                }            }
        }    }
}以上的代码，如果在控件里给  picturePath 赋值：     
 private string picturePath = "c:\\abc.bmp";             //问题在这里＝＝＝＝＝＝＝＝＝＝＝＝＝＝可是实现效果，但是如果在设计期给这个控件的F2Path属性赋值就没用怎么解决啊？

Answer 1

picturebox的image属性又不能override

Answer 2

没有很清楚的了解lz的意思，不过我想一下代码：
/// <summary> 
/// 图片来源路径 
/// </summary> 
[Category("F2")] 
[DefaultValue("")] 
[Description("图片来源路径")] 
public string F2Path 
{ 
   get { return picturePath; } 
   set { picturePath = value; } 
} 
其中set之后是否应该进行通知变化以便进行render操作
set 
{ 
   picturePath = value; 
   //此处添加通知方法
   this.OnF2PathChanged();
}private void OnF2PathChanged()
{
   this.Invalidate();
   //Or do sth...
}