Get File Icon used by Shell

Question

In .Net (C# or VB: don't care), given a file path string, FileInfo struct, or FileSystemInfo struct for a real existing file, how can I determine the icon(s) used by the shell (explorer) for that file?

I'm not currently planning to use this for anything, but I became curious about how to do it when looking at this question and I thought it would be useful to have archived here on SO.

Answer 1

Imports System.Drawing
Module Module1

    Sub Main()    
        Dim filePath As String =  "C:\myfile.exe"  
        Dim TheIcon As Icon = IconFromFile(filePath)  

        If TheIcon IsNot Nothing Then    
            ''#Save it to disk, or do whatever you want with it.
            Using stream As New System.IO.FileStream("c:\myfile.ico", IO.FileMode.CreateNew)
                TheIcon.Save(stream)          
            End Using
        End If
    End Sub

    Public Function IconFromFilePath(filePath As String) As Icon
        Dim result As Icon = Nothing
        Try
            result = Icon.ExtractAssociatedIcon(filePath)
        Catch ''# swallow and return nothing. You could supply a default Icon here as well
        End Try
        Return result
    End Function
End Module

Answer 2

This link seems to have some info. It involves a lot of registry traversing, but it seems doable. The examples are in C++

Answer 3

• determine extension
• in registry, go to "HKCR\.{extension}", read the default value (let's call it filetype)
• in "HKCR\{filetype}\DefaultIcon", read the default value: this is the path to the icon file (or icon container file, like an .exe with an embedded icon resource)
• if needed, use your preferred method of extracting the icon resource out of the mentioned file

edit/moved up from the comments:

If the icon is in a container file (this is quite common), there will be a counter after the path, like this: "foo.exe,3". This means it is icon number 4 (the index is zero-based) of the available icons. A value of ",0" is implicit (and optional). If the counter is 0 or missing, the fist available icon will be used by the shell.

Answer 4

Please ignore everyone telling you to use the registry! The registry is NOT AN API. The API you want is SHGetFileInfo with SHGFI_ICON. You can get a P/Invoke signature here:

http://www.pinvoke.net/default.aspx/shell32.SHGetFileInfo

Answer 5

You should use SHGetFileInfo.

Icon.ExtractAssociatedIcon works just as well as SHGetFileInfo in most cases, but SHGetFileInfo can work with UNC paths (e.g. a network path like "\\ComputerName\SharedFolder\") while Icon.ExtractAssociatedIcon cannot. If you need or might need to use UNC paths, it would be best to use SHGetFileInfo instead of Icon.ExtractAssociatedIcon.

This is good CodeProject article on how to use SHGetFileInfo.