c# 如何读取程序集中的描述、公司名称、版权等信息？

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Reflection;
namespace WindowsFormsApplication11
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        private void Form1_Load(object sender, EventArgs e)
        {
            Assembly asm = Assembly.GetExecutingAssembly();//如果是当前程序集
            //如果是其他文件
            //string filename = Application.StartupPath + "\\xxx.exe";
            //Assembly asm = Assembly.LoadFile(filename);
            AssemblyDescriptionAttribute asmdis = (AssemblyDescriptionAttribute)Attribute.GetCustomAttribute(asm, typeof(AssemblyDescriptionAttribute));
            AssemblyCopyrightAttribute asmcpr = (AssemblyCopyrightAttribute)Attribute.GetCustomAttribute(asm, typeof(AssemblyCopyrightAttribute));
            AssemblyCompanyAttribute asmcpn = (AssemblyCompanyAttribute)Attribute.GetCustomAttribute(asm, typeof(AssemblyCompanyAttribute));
            string s = string.Format("{0}  {1}  {2} ", asmdis.Description, asmcpr.Copyright, asmcpn.Company);
            MessageBox.Show(s);
        }
    }
}