VB.NET Display file icons from Network Paths with calling Shell - vb.net

Question

I have this program that shows files with its icons using a ListView and it works a little bit fine but there's a problem, some files(.exe, .docx etc...) don't show their right icon like this. how do I fix that?
This is how I call the Shell:
' declare the Win32 API function SHGetFileInfo'
Public Declare Auto Function SHGetFileInfo Lib "shell32.dll" (ByVal pszPath As String, ByVal dwFileAttributes As Integer, ByRef psfi As SHFILEINFO, ByVal cbFileInfo As Integer, ByVal uFlags As Integer) As IntPtr
' declare some constants that SHGetFileInfo requires'
Public Const SHGFI_ICON As Integer = &H100
Public Const SHGFI_SMALLICON As Integer = &H1
' define the SHFILEINFO structure'
Structure SHFILEINFO
Public hIcon As IntPtr
Public iIcon As Integer
Public dwAttributes As Integer
<Runtime.InteropServices.MarshalAs(Runtime.InteropServices.UnmanagedType.ByValTStr, SizeConst:=260)> _
Public szDisplayName As String
<Runtime.InteropServices.MarshalAs(Runtime.InteropServices.UnmanagedType.ByValTStr, SizeConst:=80)> _
Public szTypeName As String
End Structure
Function RetrieveShellIcon(ByVal argPath As String) As Image
Dim mShellFileInfo As SHFILEINFO
Dim mSmallImage As IntPtr
Dim mIcon As System.Drawing.Icon
Dim mCompositeImage As Image
mShellFileInfo = New SHFILEINFO
mShellFileInfo.szDisplayName = New String(Chr(0), 260)
mShellFileInfo.szTypeName = New String(Chr(0), 80)
mSmallImage = SHGetFileInfo(argPath, 0, mShellFileInfo, System.Runtime.InteropServices.Marshal.SizeOf(mShellFileInfo), SHGFI_ICON Or SHGFI_SMALLICON)
' create the icon from the icon handle'
Try
mIcon = System.Drawing.Icon.FromHandle(mShellFileInfo.hIcon)
mCompositeImage = mIcon.ToBitmap
Catch ex As Exception
' create a blank black bitmap to return'
mCompositeImage = New Bitmap(16, 16)
End Try
' return the composited image'
Return mCompositeImage
End Function
Function GetIcon(ByVal argFilePath As String) As Image
Dim mFileExtension As String = System.IO.Path.GetExtension(argFilePath)
' add the image if it doesn't exist'
If cIcons.ContainsKey(mFileExtension) = False Then
cIcons.Add(mFileExtension, RetrieveShellIcon(argFilePath))
End If
' return the image'
Return cIcons(mFileExtension)
End Function
and this is how I show file icons in my `ListView.
Sub lv1items()
Dim lvi As ListViewItem
Dim di As New DirectoryInfo(Form2.TextBox1.Text)
Dim exts As New List(Of String)
ImageList1.Images.Clear()
If di.Exists = False Then
MessageBox.Show("Source path is not found", "Directory Not Found", MessageBoxButtons.OK, MessageBoxIcon.Error)
Else
For Each fi As FileInfo In di.EnumerateFiles("*.*")
lvi = New ListViewItem
lvi.Text = fi.Name
lvi.SubItems.Add(((fi.Length / 1024)).ToString("0.00"))
lvi.SubItems.Add(fi.CreationTime.ToShortDateString)
If exts.Contains(fi.Extension) = False Then
Dim mShellIconManager As New Form1
For Each mFilePath As String In My.Computer.FileSystem.GetFiles(Form2.TextBox1.Text)
ImageList1.Images.Add(fi.Extension, GetIcon(mFilePath))
exts.Add(fi.Extension)
Next
End If
lvi.ImageKey = fi.Extension
ListView1.Items.Add(lvi)
Next
End If
End Sub

Answer 1

That appears to be a weird limitation of the .net implication
its really just making a call to shell32.dll
You should call the function in shell32 directly
something like this should work
<DllImport("shell32.dll")>
Private Shared Function ExtractAssociatedIcon(hInst As IntPtr, lpIconPath As StringBuilder, ByRef lpiIcon As UShort) As IntPtr
End Function
_
Dim handle As IntPtr = SafeNativeMethods.ExtractAssociatedIcon(New HandleRef(Nothing, IntPtr.Zero), iconPath, index)
If handle <> IntPtr.Zero Then
Return Icon.FromHandle(handle)
End If
The syntax might not be exactly correct, also there is a good blog post about how to pull that information from the registry (which won't always give you the correct answer, but its faster)
Building a Better ExtractIcon (he uses the SHGetFileInfo API in shell32.dll if that blog ever dies it will give people a place to start looking)