OSIcon

Introduction
Using the code

Classes in the library
Using the IconReader class
Using the IconManager class

History

Introduction

This library can retrieve icons from extensions and files, with additional information like file type (hard drive, folder, PHP Script File, ...). The library also provides a class for CACHE icons and creates an ImageList with the added icons.

Using the code

Classes in the library

WinAPI namespace (Contains all Win API calls)

Shell32 static class (all API calls for Shell32.dll)
Shell32Vista static class (all API calls for Shell32.dll)
User32 static class (all API calls for User32.dll)
Comctl32 static class (all API calls for Comctl32.dll)
Kernel32 static class (all API calls for Kernel32.dll)
IEnumIDList interface
IShellFolder interface

Utils static class (helper functions)
IconReader static class (read, handle icons)
IconManager class (IconReader wrapper with caching features, automatic creation of ImageList)
About static class (stores some constants about the library, author, webpage, etc...)

Using the IconReader class

Get any icon from a file using "OSIcon.IconReader.ExtractIconFromFile(path, isLarge);".

// To extract the file icon we simply can do:
// First param will be the path to file.
// Last param define icon size (true = Large, false = Small)
Icon icon = OSIcon.IconReader.ExtractIconFromFile("C:\\pathtofile.png", true);

Now, if you want to extract an icon from a resource file like shell32.dll, you can do: "OSIcon.IconReader.ExtractIconFromFile(path, iconIndex);".

// 5, is the icon index
// http://cfs6.tistory.com/upload_control/download.blog?
// fhandle=YmxvZzEwMTUzNkBmczYudGlzdG9yeS5jb206L2F0dGFjaC8wLzAxMDAwMDAwMDAwMC5qcGc%3D
// 5 will return Open Folder image from shell32.dll
Icon icon = OSIcon.IconReader.ExtractIconFromFile("C:\\Windows\\system32\\shell32.dll", 5);

In Windows Explorer, FileZilla, etc., we can see the file type (Folder, PHP Script, Dynamic Link Library, etc.). To retrieve that information, we need to use some API calls. Using OSIcon, this is quite simple: "OSIcon.IconReader.GetFileIcon(pathOrExtension, IconReader.IconSize, Shell32.SHFILEINFO);".

// NOTE: filename can be an partial extension (.png), or a full path ("C:\\file.png")
// shfi, store some file information
OSIcon.WinAPI.Shell32.SHFILEINFO shfi = new Shell32.SHFILEINFO();
Icon icon = OSIcon.IconReader.GetFileIcon(".png", IconReader.IconSize.Large, false, ref shfi);
MessageBox.Show(string.Format("Display Name: {0}\nFile Type: {1}", 
                shfi.szDisplayName, shfi.szTypeName));

We can also retrieve file extensions from regedit and extract their icons, using: "OSIcon.IconReader.GetFileTypeAndIcon();".

// Get all available extensions
// Dictionary Key = extension, value = path to icon
Dictionary<string, string> _iconList = _iconList = 
OSIcon.IconReader.GetFileTypeAndIcon();
// Foreach each extension
foreach (KeyValuePair<string, string> list in _iconList)
// Extract icon from file
Icon icon = OSIcon.IconReader.ExtractIconFromFile(_iconList[extension], 
                              isLarge ? true : false);

Getting all icons on a file is quite simple, using: "ExtractIconsFromFile(path, isLarge);".

// From Sample Application see: "IconExplorer.cs" UserControl
filename = "C:\\Windows\\system32\\shell.dll";
Icon[] icons = IconReader.ExtractIconsFromFile(filename, true);
if(icons.Length == 0) return; // No icons found, return
// Loop through icons array
for (int i = 0; i < icons.Length; i++)
{
    // Do something here, im adding icon to an ImageList
    imageList.Images.Add(i.ToString(), icons[i]);
}

Using the IconManager class

Sometimes we need to display our files and have 100s of files of the same type, e.g., .php; you can reuse icons obtained from the first PHP file in that case.

IconProperties class

IconsInfo (stores icons information) Dictionary<IconReader.IconSize, Shell32.SHFILEINFO>
IconsIndex (icons index from ImageList) Dictionary<IconReader.IconSize, int>
Icons (stores icons image) Dictionary<IconReader.IconSize, Icon>

// If you want create a ImageList to store collected icons use true
// Small ImageList (true/false), Large ImageList (true/false)
// new OSIcon.IconManager() == new OSIcon.IconManager(true, true)
//
// Initalize Class, and create small, large, extralarge, jumbo
// Last param if set true, disable ExtraLarge or Jumbo if not supported by current OS
OSIcon.IconManager iconManager = new OSIcon.IconManager(true, true, true, true, true);
// Add some special icons to be used
// Add folder images
iconManager.AddFolder(iconManager.IconSizeAllSupported); 
// Add Computer Drives (DVD Drive, Floppy, Hard Disk, etc.)
iconManager.AddComputerDrives(iconManager.IconSizeAllSupported); 
 
// You also can add manualy, icons images to ImageList
// I use ":" because file path can't have ':' in name, so its a special mark
iconManager.IImageList[IconReader.IconSize.Small].Images.Add(
  ":Up-icon:", Properties.Resources.Up_icon16x16);
iconManager.IImageList[IconReader.IconSize.Large].Images.Add(
  ":Up-icon:", Properties.Resources.Up_icon32x32);
// ExtraLarge was instroduced on XP so if you running XP
// or above add ExtraLarge capabilities
if (OSIcon.Utils.IsXpOrAbove())
{
    iconManager.IImageList[IconReader.IconSize.ExtraLarge].Images.Add(
                ":Up-icon:", Properties.Resources.Up_icon48x48);
}
// Jumbo was instroduced on Vista so if you
// running Vista or above add Jumbo capabilities
if (OSIcon.Utils.IsVistaOrAbove())
{
    iconManager.IImageList[IconReader.IconSize.Jumbo].Images.Add(
          ":Up-icon:", Properties.Resources.Up_icon256x256);
}
// NOTE: iconManager.IImageList[IconReader.Size]
// can be assign in any control that uses ImageList

The class is initialized and ready to use; now, we create a function to show My Computer and the path contents:

void ShowMyComputer()
{
    // List all drives on computer
    foreach (string drive in Directory.GetLogicalDrives())
    {
        // Always when you add a icon to list it will return IconProperties 
        // and cache it on class
        OSIcon.IconManager.IconProperties iconProp = 
          OSIcon.iconManager.AddEx(drive, IconManager.IconSizeBoth);
        // Do something here!, sample from OSIcon Explorer:
        ListViewItem item = new ListViewItem(
          iconProp.IconsInfo[IconReader.IconSize.Small].szDisplayName);
        item.ImageIndex = iconProp.IconsIndex[IconReader.IconSize.Small];
        item.SubItems.Add(""); // Size
        item.SubItems.Add(iconProp.IconsInfo.Small.szTypeName); // Type name
        item.Tag = drive;
    }
}
 
// Next function will show path contents
public void ShowPathContents(string path)
{
    if (path == null) return;
    // If path is empty show my computer instead
    if (path == "") 
    {
        ShowMyComputer();
        return;
    }
    try
    {
        Cursor = Cursors.WaitCursor;
        string[] folders = Directory.GetDirectories(path);
        string[] files = Directory.GetFiles(path);
        foreach (string folder in folders) // get all folders on a path
        {
            DirectoryInfo dirInfo = new DirectoryInfo(folder);
            // Your Code go here!, sample from OSIcon Explorer
            ListViewItem item = new ListViewItem(Path.GetFileName(folder));
            item.Tag = folder;
            // Its a folder and its already added when we initalized the class, 
            // so we can directly get by:
            // Note: Make use of OSIcon.IconManager.FolderOpen and 
            // OSIcon.IconManager.FolderClosed constants
            IconManager.IconProperties iconProp = 
                iconManager.IconList[OSIcon.IconManager.FolderClosed];
            // we assign ImageList icon index to Image, you can use image 
            // key instead
            item.ImageIndex = iconProp.IconsIndex[IconReader.IconSize.Small];
            item.SubItems.Add("");
            item.SubItems.Add(iconProp.IconsInfo[IconReader.IconSize.Small].szTypeName);
            item.SubItems.Add(dirInfo.LastWriteTime.ToString());
            fileExplorerList.Items.Add(item);
        }
        foreach (string file in files)
        {
            FileInfo fi = new FileInfo(file);
            // Your Code go here!, sample from OSIcon Explorer
            // Now its a file, and we need try add the icon to class, if that 
            // icon already exist on class, will return the icon previous added
            // otherwise add and return.
            // I perfer use by extension because its easier to cache, because
            // 100 times .php is not the same as 100 times diferentFileNames.php
            IconManager.IconProperties iconProp = iconManager.AddEx(fi.Extension, 
                                                  IconManager.IconSizeAllSupported);
            ListViewItem item = new ListViewItem(fi.Name);
            item.Tag = fi.FullName;
            item.ImageIndex = iconProp.IconsIndex[IconReader.IconSize.Small];
            item.SubItems.Add(fi.Length.ToString());
            item.SubItems.Add(iconProp.IconsInfo[IconReader.IconSize.Small].szTypeName);
            item.SubItems.Add(fi.LastWriteTime.ToString());
        }
    }
    catch (Exception ex)
    {
        MessageBox.Show(string.Format("Error on trying acess: {0}\n\n{1}", 
                                      path, ex.Message), 
                                      "Error", 
                                      MessageBoxButtons.OK, 
                                      MessageBoxIcon.Error);
    }
    finally
    {
        Cursor = Cursors.Default;
    }
}

ListView only has an "ImageList" (should be 16 x 16px) and "LargeImageList". If you want to show "ExtraLarge" icons introduced in XP, and "Jumbo" from Vista or above, you have to change "LargeImageList" to the desired size, like:

/* 
* "fileExplorerList" is our ListView
* View:
* 0 = LargeIcons
* 1 = Details
* 2 = Small Icons
* 3 = List
* 4 = Title
* End View Enumeration
* 5 = ExtraLarge
* 6 = Jumbo
*/

private void ChangeListViewV(uint index)
{
    // If view is bigger than 4 means user wants ExtraLarge or Jumbo
    // To show that sizes View must be set to: View.LargeIcon
    // Also we have to change Large ImageList to the disired one
    if (index > 4)
    {
        // we change ImageList because ListView only have ImageList and LargeImageList
        switch (index)
        {
           case 5:
              fileExplorerList.LargeImageList = 
                    iconManager.IImageList[IconReader.IconSize.ExtraLarge];
              break;
           case 6:
              fileExplorerList.LargeImageList = 
                    iconManager.IImageList[IconReader.IconSize.Jumbo];
              break;
        }
        fileExplorerList.View = View.LargeIcon;
        return;
     }
     // View is under normal (small or large)
     // Get back to normal
     fileExplorerList.LargeImageList = iconManager.IImageList[IconReader.IconSize.Large];
     fileExplorerList.View = (View)index;
}

How can you get rid of of the added icons? It can be done like so:

// I dont need .txt icon anymore, and i will not use it from ImageList
iconManager.Remove(".txt", true);
// I dont need .wav icon anymore, but i still use it from ImageList
iconManager.Remove(".wav", false);
// IconSize Small is to small and Jumbo is too big for what i want
iconManager.Remove(".exe", IconReader.IconSize.Small | 
                                     IconReader.IconSize.Jumbo, true);

You need not hard-code with the IconManager class. Here is an example:

string name = ".dll";

// Bad Way:
IconProperties iconProp = iconManager.IconList[name];
if(!iconProp.IsValid(name, IconReader.IconSize.Small))
{
    OSIcon.WinAPI.Shell32.SHFILEINFO shfi = new Shell32.SHFILEINFO();
    iconManager.AddEx(name, IconReader.IconSize.Small, ref shfi);
}
if(!iconProp.IsValid(name, IconReader.IconSize.Jumbo))
{
    OSIcon.WinAPI.Shell32.SHFILEINFO shfi = new Shell32.SHFILEINFO();
    iconManager.AddEx(name, IconReader.IconSize.Jumbo, ref shfi);
}

// Good Way:
OSIcon.WinAPI.Shell32.SHFILEINFO shfi = new Shell32.SHFILEINFO();
IconProperties iconProp = iconManager.AddEx(name, 
     IconReader.IconSize.Small | IconReader.IconSize.Jumbo, ref shfi);

History

V2.0

Added About class
Added better commentaries
Added more samples
Updated sample application to use new icon sizes
Updated sample application to use the new library

IconProperties class

Added the "Remove" function, to remove an icon from a specified size

Supports multi sizes flags (IconReader.IconSize.Small | IconReader.IconSize.Large)
Returns a Dictionary<IconReader.IconSize, int> with removed icons, where int is the icon index on the ImageList

Added three "IsValid" functions

bool IsValidEx(IconReader.IconSize size), same as "IsValid(IconReader.IconSize size)", but also checks if the icon is not NULL
bool IsValid(), checks if that instance contains an icon
bool IsValid(IconReader.IconSize size), checks if an icon of a specified size exists in that instance

Changed "IconsInfo" type from struct to Dictionary<IconReader.IconSize, Shell32.SHFILEINFO>
Changed "IconsIndex" type from struct to Dictionary<IconReader.IconSize, int>
Changed "Icons" type from struct to Dictionary<IconReader.IconSize, Icon>
Implemented a "Tag" object
Disposable class
"IconProperties" is now a class, was a struct before

IconManager class

Fixed the "AddEx" function to allow adding more icons of different sizes
Added commentaries
Added two "Remove" functions, allows removing icons from the cache and from the ImageList

bool Remove(string path, bool removeIconFromList), removes all icons
bool Remove(string path, IconReader.IconSize iconSize, bool removeIconFromList), removes icons of a specified size only

Added private "Add" function, common actions when adding icons to list (to remove redundancy)
Added "IsValidEx" function, same as "IsValid", but returns the matched "IconProperties"; otherwise returns a new instance
Added two new constructors

public IconManager(bool createSmallIconList, bool createLargeIconList, bool createExtraLargeIconList, bool createJumboIconList)
public IconManager(bool createSmallIconList, bool createLargeIconList, bool createExtraLargeIconList, bool createJumboIconList, bool optimizeToOS)

Replaced "ImageListSmall" and "ImageListLarge" ImageLists with "IImageList" Dictionary<IconReader.IconSize, ImageList>
Added "IconSizeAllSupported" readeonly variable, contains all icon sizes supported by the current OS
Added "IconManager.IconSizeAll" constant, contains all icon sizes (Small | Large | ExtraLarge | Jumbo)

IconReader class

Changed all functions that contain a "IconReader.IconSize" to support new icon sizes (ExtraLarge, Jumbo)
Added the "ExtractIconFromResource" function, extracts an icon by name from the assembly
Added the "ExtractIconsFromFile" function, extracts all icons from a file; returns "Icon[]"
Added the "ExtractIconFromFileEx" function, identical to ExtractIconFromFile, but supports bigger sizes and icon information
Added two new icon sizes to "IconReader.IconSize"