SHGetFileInfo (shell32)
Last changed: Vasily-178.121.89.146

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Summary

C# Signatures:

[DllImport("shell32.dll")]
static extern IntPtr SHGetFileInfo(string pszPath, uint dwFileAttributes,
   out SHFILEINFO psfi, uint cbFileInfo, uint uFlags);

[DllImport("shell32.dll",
   SetLastError=true,
   EntryPoint="SHGetFileInfo",
   CharSet=CharSet.Auto,
   BestFitMapping=false,
   ThrowOnUnmappableChar=true)]
static extern IntPtr ApiSHGetFileInfo
   (string pszPath, uint dwFileAttributes,ref SHFILEINFO psfi,
   uint cbSizeFileInfo, uint uFlags);

User-Defined Types:

None.

Notes:

None.

Tips & Tricks:

Please add some!

For a whole winform sample of Displayname see http://Dzaebel.NET/ShGetFileInfo.htm

Sample Code:

    //
    // Modified http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&selm=uMD%23VHmqBHA.2368%40tkmsftngp03&rnum=4
    //

    using System;
    using System.Runtime.InteropServices;
    using System.Drawing;

    /// <summary> Summary description for ExtractIcon.</summary>
    public class ExtractIcon
    {
    [DllImport("shell32.dll", CharSet=CharSet.Auto)]
    private static extern int  SHGetFileInfo(
      string pszPath     ,
      int    dwFileAttributes,
      out    SHFILEINFO psfi ,
      uint   cbfileInfo      ,
      SHGFI  uFlags );

    /// <summary>Maximal Length of unmanaged Windows-Path-strings</summary>
    private const int MAX_PATH = 260;
    /// <summary>Maximal Length of unmanaged Typename</summary>
    private const int MAX_TYPE = 80 ;

    [StructLayout(LayoutKind.Sequential, CharSet=CharSet.Auto)]
    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.ByValTStr, SizeConst=MAX_PATH)]
      public string szDisplayName;
      [MarshalAs(UnmanagedType.ByValTStr, SizeConst=MAX_TYPE)]
      public string szTypeName;
    };

    private ExtractIcon()
    {
    }

    [Flags]
    enum SHGFI : int
    {
      /// <summary>get icon</summary>
      Icon         = 0x000000100,  
      /// <summary>get display name</summary>
      DisplayName      = 0x000000200,
      /// <summary>get type name</summary>
      TypeName     = 0x000000400,
      /// <summary>get attributes</summary>
      Attributes       = 0x000000800,
      /// <summary>get icon location</summary>
      IconLocation     = 0x000001000,  
      /// <summary>return exe type</summary>
      ExeType      = 0x000002000,  
      /// <summary>get system icon index</summary>
      SysIconIndex     = 0x000004000,  
      /// <summary>put a link overlay on icon</summary>
      LinkOverlay      = 0x000008000,  
      /// <summary>show icon in selected state</summary>
      Selected     = 0x000010000,  
      /// <summary>get only specified attributes</summary>
      Attr_Specified   = 0x000020000,  
      /// <summary>get large icon</summary>
      LargeIcon    = 0x000000000,  
      /// <summary>get small icon</summary>
      SmallIcon    = 0x000000001,  
      /// <summary>get open icon</summary>
      OpenIcon     = 0x000000002,  
      /// <summary>get shell size icon</summary>
      ShellIconSize     = 0x000000004,  
      /// <summary>pszPath is a pidl</summary>
      PIDL         = 0x000000008,  
      /// <summary>use passed dwFileAttribute</summary>
      UseFileAttributes= 0x000000010,  
      /// <summary>apply the appropriate overlays</summary>
      AddOverlays      = 0x000000020,  
      /// <summary>Get the index of the overlay in the upper 8 bits of the iIcon</summary>
      OverlayIndex     = 0x000000040,  
    }  

    /// <summary>
    /// Get the associated Icon for a file or application, this method always returns
    /// an icon.  If the strPath is invalid or there is no idonc the default icon is returned
    /// </summary>
    /// <param name="strPath">full path to the file</param>
    /// <param name="bSmall">if true, the 16x16 icon is returned otherwise the 32x32</param>
    /// <returns></returns>
    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);
    }
    }

Alternative Managed API #1:

    /// <summary>
    /// Summary description for ShellIcon.  Get a small or large Icon with an easy C# function call
    /// that returns a 32x32 or 16x16 System.Drawing.Icon depending on which function you call
    /// either GetSmallIcon(string fileName) or GetLargeIcon(string fileName)
    /// </summary>
    public class ShellIcon
    {
        [StructLayout(LayoutKind.Sequential)]
        public struct SHFILEINFO
        {
            public IntPtr hIcon;
            public IntPtr iIcon;
            public uint dwAttributes;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 260)]
            public string szDisplayName;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 80)]
            public string szTypeName;
        };

        class Win32
        {
            public const uint SHGFI_ICON = 0x100;
            public const uint SHGFI_LARGEICON = 0x0; // 'Large icon
            public const uint SHGFI_SMALLICON = 0x1; // 'Small icon

            [DllImport("shell32.dll")]
            public static extern IntPtr SHGetFileInfo(string pszPath, uint dwFileAttributes, ref SHFILEINFO psfi,             uint cbSizeFileInfo, uint uFlags);
        }

        public ShellIcon()
        {
            //
            // TODO: Add constructor logic here
            //
        }

        public static Icon GetSmallIcon(string fileName)
        {
            IntPtr hImgSmall; //the handle to the system image list
            SHFILEINFO shinfo = new SHFILEINFO();

            //Use this to get the small Icon
            hImgSmall = Win32.SHGetFileInfo(fileName, 0, ref shinfo,(uint)Marshal.SizeOf(shinfo),Win32.SHGFI_ICON                              | Win32.SHGFI_SMALLICON);

            //The icon is returned in the hIcon member of the shinfo struct
            return System.Drawing.Icon.FromHandle(shinfo.hIcon);        
        }

        public static Icon GetLargeIcon(string fileName)
        {
            IntPtr hImgLarge; //the handle to the system image list
            SHFILEINFO shinfo = new SHFILEINFO();

            //Use this to get the large Icon
            hImgLarge = Win32.SHGetFileInfo(fileName, 0, ref shinfo, (uint)Marshal.SizeOf(shinfo),                                      Win32.SHGFI_ICON | Win32.SHGFI_LARGEICON);

            //The icon is returned in the hIcon member of the shinfo struct
            return System.Drawing.Icon.FromHandle(shinfo.hIcon);        
        }
    }

Alternative Managed API:

Do you know one? Please contribute it!

Documentation

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sathya