从文件中提取Ico图标，支持拖拽

时间：2010-08-18 来源：无意创新

调用核心类class ExtractIcon
    {
        [DllImport("Shell32.dll")]
        private static extern int SHGetFileInfo
        (
        string pszPath,
        uint dwFileAttributes,
        out   SHFILEINFO psfi,
        uint cbfileInfo,
        SHGFI uFlags
        );

        [StructLayout(LayoutKind.Sequential)]
        private struct SHFILEINFO
        {
            public SHFILEINFO(bool b)
            {
                hIcon = IntPtr.Zero; iIcon = 0; dwAttributes = 0; szDisplayName = ""; szTypeName = "";
            }
            public IntPtr hIcon;
            public int iIcon;
            public uint dwAttributes;
            [MarshalAs(UnmanagedType.LPStr, SizeConst = 260)]
            public string szDisplayName;
            [MarshalAs(UnmanagedType.LPStr, SizeConst = 80)]
            public string szTypeName;
        };

        private ExtractIcon()
        {
        }

        private enum SHGFI
        {
            SmallIcon = 0x00000001,
            LargeIcon = 0x00000000,
            Icon = 0x00000100,
            DisplayName = 0x00000200,
            Typename = 0x00000400,
            SysIconIndex = 0x00004000,
            UseFileAttributes = 0x00000010
        }


        public static Icon GetIcon(string strPath, bool bSmall)
        {
            SHFILEINFO info = new SHFILEINFO(true);
            int cbFileInfo = Marshal.SizeOf(info);
            SHGFI flags;
            if (bSmall)
                flags = SHGFI.Icon | SHGFI.SmallIcon | SHGFI.UseFileAttributes;
            else
                flags = SHGFI.Icon | SHGFI.LargeIcon | SHGFI.UseFileAttributes;

            SHGetFileInfo(strPath, 256, out   info, (uint)cbFileInfo, flags);
            return Icon.FromHandle(info.hIcon);
        }
    }

窗体类

public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_DragDrop(object sender, DragEventArgs e)
        {
            string path = ((System.Array)e.Data.GetData(DataFormats.FileDrop)).GetValue(0).ToString();

            SaveIcon(path);
        }

        private void Form1_DragEnter(object sender, DragEventArgs e)
        {
            if (e.Data.GetDataPresent(DataFormats.FileDrop))
            {
                e.Effect = DragDropEffects.Copy;
            }
            else
            {
                e.Effect = DragDropEffects.None;
            }
        }

        private void button1_Click(object sender, EventArgs e)
        {
            if (this.openFileDialog1.ShowDialog() == DialogResult.OK)
            {
                if (this.openFileDialog1.OpenFile() != null)
                {
                    SaveIcon(this.openFileDialog1.FileName);
                   
                }
            }
        }

        public void SaveIcon(string path)
        {
            Icon icon = ExtractIcon.GetIcon(path, false);
            string name = path.Substring(path.LastIndexOf("\\"), path.LastIndexOf(".") - path.LastIndexOf("\\") + 1);
           string svaepath=Application.StartupPath + name+"ico";
           FileStream fs = null;
           try
           {
               fs = new FileStream(svaepath, FileMode.Create, FileAccess.Write);
               icon.Save(fs);
               fs.Flush();
               fs.Close();
              
           }
           catch (Exception ex)
           {

               ex.ToString();
               MessageBox.Show("未知错误","提取失败");
           }
           finally
           {
               if (fs != null)
               {
                   fs.Close();
               }
           }


           MessageBox.Show("已保存" + svaepath,"提取成功");
        }
    }

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