IconEx.cs

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

/// <summary>
/// Provides additional icon-related functionality.
/// </summary>
public static class IconEx
{
    [DllImport("shell32.dll", EntryPoint = "ExtractAssociatedIcon", CharSet = CharSet.Auto)]
    internal static extern IntPtr ExtractAssociatedIcon(
        HandleRef hInst,
        StringBuilder iconPath,
        ref int index);

    /// <summary>
    /// Returns an icon representation of an image that is contained in the specified file.
    /// This is identical to Icon.ExtractAssociatedIcon, except that it works when filePath
    /// is on a network share.
    /// </summary>
    /// <param name="filePath">The path to the file that contains an image.</param>
    /// <returns>
    /// The System.Drawing.Icon representation of the image that is contained in the
    /// specified file.
    /// </returns>
    public static Icon ExtractAssociatedIcon(string filePath)
    {
        int index = 0;
        StringBuilder iconPath = new StringBuilder(filePath);
        IntPtr handle = ExtractAssociatedIcon(
            new HandleRef(null, IntPtr.Zero),
            iconPath,
            ref index);

        if (handle != IntPtr.Zero)
        {
            return Icon.FromHandle(handle);
        }

        return null;
    }
}