Get full quality 16 x 16 icon using Icon.ExtractAssociatedIcon and ImageList

Answer 1

You have to use 2 imagelists, one for smallimages and one for largeimages to get the best result I think. (The listview has two properties, LargeImageList and SmallImageList)

Edit (found new information that worked when I tried):

This version are using interpolation to get the smaller thumb, should be better.

    Dim BigIcon As Icon = Nothing
    BigIcon = Icon.ExtractAssociatedIcon("c:\zebra.zip")
    Dim largeimages As New ImageList
    Dim smallimages As New ImageList

    largeimages.Images.Add("1", BigIcon)

    'Fix a smaller version with interpolation
    Dim bm As New Bitmap(BigIcon.ToBitmap)
    Dim thumb As New Bitmap(16, 16)
    Dim g As Graphics = Graphics.FromImage(thumb)
    g.InterpolationMode = Drawing2D.InterpolationMode.HighQualityBicubic
    g.DrawImage(bm, New Rectangle(0, 0, 16, 16), New Rectangle(0, 0, bm.Width, bm.Height), GraphicsUnit.Pixel)
    g.Dispose()
    bm.Dispose()
    smallimages.Images.Add("1", thumb)
    ListView1.SmallImageList = smallimages
    ListView1.LargeImageList = largeimages
    thumb.Dispose()
    ListView1.Items.Add("Test", "Test", "1")

Answer 2

With this Code Project Article and the Demo of ExtractIconEx from PInvoke (http://www.pinvoke.net/default.aspx/shell32/ExtractIconEx.html) you can write the following:

FileAssociationInfo info = new FileAssociationInfo(".docx");

ProgramAssociationInfo pai = new ProgramAssociationInfo(info.ProgID);
ProgramIcon ico = pai.DefaultIcon;
Icon icoLarge = Martin.Hyldahl.Examples.ExtractIconEx.ExtractIconExample.ExtractIconFromExe(ico.Path, ico.Index, false);

you have to change the signature of ExtractIconFromExe to

public static Icon ExtractIconFromExe(string file, int nIconIndex, bool large)

and change the code a few lines down to

if (large)
   readIconCount = ExtractIconEx(file, nIconIndex, hIconEx, hDummy, 1);
else
   readIconCount = ExtractIconEx(file, nIconIndex, hDummy, hIconEx, 1);