public static Icon GetIconForExtension(string extension)
{
if (!extensionIcons.ContainsKey(extension))
{
Icon ic = ExtendedFileInfo.GetExtensionIcon(extension, true);
if (ic == null)
{
throw new NullReferenceException("Icon for extension: " + extension);
}
extensionIcons[extension] = ic;
}
return(extensionIcons[extension]);
}