Imports System
Imports System.Collections.Generic
Imports System.ComponentModel
Imports System.Data
Imports System.Drawing
Imports System.Text
Imports System.Windows.Forms
Imports System.Runtime.InteropServices
 
Namespace ExtractIcon
    Partial Public Class Form1
        Inherits Form
        ' Constants that we need in the function call
        Private Const SHGFI_ICON As Integer = &H100
        Private Const SHGFI_SMALLICON As Integer = &H1
        Private Const SHGFI_LARGEICON As Integer = &H0
 
        ' This structure will contain information about the file
        Public Structure SHFILEINFO
            ' Handle to the icon representing the file
            Public hIcon As IntPtr
            ' Index of the icon within the image list
            Public iIcon As Integer
            ' Various attributes of the file
            Public dwAttributes As UInteger
            ' Path to the file
            <MarshalAs(UnmanagedType.ByValTStr, SizeConst:=256)> _
            Public szDisplayName As String
            ' File type
            <MarshalAs(UnmanagedType.ByValTStr, SizeConst:=80)> _
            Public szTypeName As String
        End Structure
        ' The signature of SHGetFileInfo (located in Shell32.dll)
 
        <DllImport("Shell32.dll")> _
        Public Shared Function SHGetFileInfo(ByVal pszPath As String, ByVal dwFileAttributes As UInteger, ByRef psfi As SHFILEINFO, ByVal cbFileInfo As Integer, ByVal uFlags As UInteger) As IntPtr
        End Function
 
        Public Sub New()
            InitializeComponent()
        End Sub
 
        Private Sub btnExtract_Click(ByVal sender As Object, ByVal e As EventArgs)
            ' Will store a handle to the small icon
            Dim hImgSmall As IntPtr
            ' Will store a handle to the large icon
            Dim hImgLarge As IntPtr
            Dim shinfo As New SHFILEINFO()
            ' Open the file that we wish to extract the icon from
            If openFile.ShowDialog() = DialogResult.OK Then
                ' Store the file name
                Dim FileName As String = openFile.FileName
                ' Store the icon in this myIcon object
                Dim myIcon As System.Drawing.Icon
                ' Get a handle to the small icon
                hImgSmall = SHGetFileInfo(FileName, 0, shinfo, Marshal.SizeOf(shinfo), SHGFI_ICON Or SHGFI_SMALLICON)
                ' Get the small icon from the handle
                myIcon = System.Drawing.Icon.FromHandle(shinfo.hIcon)
                ' Display the small icon
                picIconSmall.Image = myIcon.ToBitmap()
                ' Get a handle to the large icon
                hImgLarge = SHGetFileInfo(FileName, 0, shinfo, Marshal.SizeOf(shinfo), SHGFI_ICON Or SHGFI_LARGEICON)
                ' Get the large icon from the handle
                myIcon = System.Drawing.Icon.FromHandle(shinfo.hIcon)
                ' Display the large icon
                picIconLarge.Image = myIcon.ToBitmap()
            End If
        End Sub
    End Class
End Namespace

Dim StartUpFolder As String
' Get the path where your app starts
StartUpFolder = Application.StartupPath
Dim MyDLLFile As String
' Append your dll's name to path
MyDLLFile = StartUpFolder & "\myicondll.DLL"

Dim myIcon As System.Drawing.Icon
' DEBUG: Load from the file
myIcon = New Icon("D:\icon.ico")
 
' Set the icon as the app's (i.e. main form's) icon
Me.Icon = myIcon