对图像进行存储和显示

以下是在.net中对图像进行存储和显示的方法，其原理是把读入的图像字节数组数据转化为string类型保存在数据库中；在显示时在由字符型转化为字节数组写入页面。
具体方法如下：
一、保存图片
 以二进制流的形式读入图片数据，转化为string保存入数据库
private string GetPhotoID()
{
    string photoid = Guid.NewGuid().ToString();
}
private string GetPhotoType(string photoname)
{
    string type = "";
    int position = photoname.LastIndexOf(".");
    if(position != -1)
        type = photoname.Substring(post+1);
    type = type.ToLower().Trim();
    if(type != "bmp" && type != "jpg" && type != "jpeg" && type != "gif")
        return null;
    return type;
}
private string GetPhotoValue()
{
    int datalength = (int) this.inputfile.PostedFile.InputStream.Length;
    byte[] _data = new BinaryReader(this.inputfile.PostedFile.InputStream).ReadBytes(datalength);
    string photodata = Convert.ToBase64String(_data);
    return photodata;
}

private string SavePhoto()
{
    if(this.inputfile.PostedFile.ContentLength>1024*1024)
        return;
    string photoname = this.inputfile.PostedFile.FileName;
    string photoid = GetPhotoID();
    string phototype = GetPhotoType(photoname)
    if(phototype == null)
        return;
    string photovalue = GetPhotoValue();
    string sqlstring = "Insert Into tablename (columnname...) values('"+photoID+"','"+phototype+"','"+photovalue+"')";
   string connectstr = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:/database/....mdb";
   OleDbConnection myconnect = new OleDbConnection(connectstr);
   myconnect.Open();
   OleDbCommand mycommand = new OleDbCommand(sqlstring,myconnect);
   mycommand.ExecuteNonQuery();
   myconnect.Close();
}
二、显示图片
把数据库中的值转化为二进制流输出
private void ShowPhotp()
{
   string type,values;
   int count;
   string connectstr = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:/database/....mdb";
   OleDbConnection myconnect = new OleDbConnection(connectstr);
   string sqlstring = "Select columns From tablename where photoID = '"+this.photoID+"' ";
   OleDbDataAdapter myadapter = new OleDbDataAdapter(sqlstring,myconnect);
   DataSet myset = new DataSet();
   myadapter.Fill(myset);
   if(myset.Tables[0].Rows.Count!=0)
   {
    type = myset.Tables[0].Rows[0][1].ToString();
    values = myset.Tables[0].Rows[0][2].ToString();
    count = values.Length;
   }
   else
   {
    return;
   }
   byte[] _bytes = new byte[count];
   _bytes = Convert.FromBase64String(values);

   Response.Clear();
   Response.Buffer = true;
   Response.Charset = "utf-8";
   switch(type)
   {
    case "jpg":
     Response.ContentType = "image/JPEG";
     break;
    case "bmp":
     Response.ContentType = "image/BMP";
     break;
    default:
     return;
   }
   Response.OutputStream.Write(_bytes,0,count);
   Response.End();
}

对图像进行存储和显示