Download the source package and you get the full working sample.
GetFiles() is not relevant to what the sample shall show.
Code:
/// <summary>
/// Put your own code here to get the files to be concatenated.
/// </summary>
static string[] GetFiles()
{
DirectoryInfo dirInfo = new DirectoryInfo("../../../../../PDFs");
FileInfo[] fileInfos = dirInfo.GetFiles("*.pdf");
ArrayList list = new ArrayList();
foreach (FileInfo info in fileInfos)
{
// HACK: Just skip the protected samples file...
if (info.Name.IndexOf("protected") == -1)
list.Add(info.FullName);
}
return (string[])list.ToArray(typeof(string));
}