C#获取软件图标

using System;
using System.Collections.Generic;
using System.Drawing;
using System.Windows.Forms;
using System.Runtime.InteropServices;
using System.IO;
namespace ShowIcon
{
            [StructLayout( LayoutKind.Sequential)]
        public struct FileInfomation 
        { 
               public IntPtr hIcon; 
            public int iIcon; 
            public int dwAttributes; 
 
            [ MarshalAs( UnmanagedType.ByValTStr, SizeConst = 260 )] 
            public string szDisplayName; 
 
            [ MarshalAs( UnmanagedType.ByValTStr, SizeConst = 80 )] 
            public string szTypeName; 
        }

    /// <summary>
    /// Description of MainForm.
    /// </summary>
    public partial class MainForm
    {
        [STAThread]
        public static void Main(string[] args)
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Application.Run(new MainForm());
        }
        

        [DllImport("shell32.dll", EntryPoint="SHGetFileInfo")] 
        public static extern int GetFileInfo(string pszPath, int dwFileAttributes, ref FileInfomation psfi, int cbFileInfo,int uFlags);
        public MainForm()
        {
            //
            // The InitializeComponent() call is required for Windows Forms designer support.
            //
            InitializeComponent();
            
            //
            // TODO: Add constructor code after the InitializeComponent() call.
            //
        }
        public static Icon GetSmallIcon(string path) 
        { 
         FileInfomation _info = new FileInfomation(); 
 
         GetFileInfo(path, 0, ref _info, Marshal.SizeOf(_info), (int)(0x000000100| 0x000000001)); 
         try 
          { 
          return Icon.FromHandle(_info.hIcon); 
          } 
          catch 
          { 
          return null; 
          } 
        }
        void Button1Click(object sender, System.EventArgs e)
        {
            this.openFileDialog1.ShowDialog();
        }
        
        void OpenFileDialog1FileOk(object sender, System.ComponentModel.CancelEventArgs e)
        {
            this.textBox1.Text=this.openFileDialog1.FileName;
            this.pictureBox1.Image=GetSmallIcon(this.openFileDialog1.FileName).ToBitmap();
        }
    }
    
}