get files in directory

//obtain the directory we’re wanting to search for files…
if (folderBrowserDialog1.ShowDialog() == DialogResult.OK) {
    folderToSearch = folderBrowserDialog1.SelectedPath; //make folderToSearch a form-level public variable
}

//if we want only top-level files (those not in subfolders of folderToSearch), then…
DirectoryInfo di = new DirectoryInfo(folderToSearch);
FileInfo[] fi = di.GetFiles(“*.*”, SearchOption.TopDirectoryOnly);

//if we want to include subdirectories in our search:
DirectoryInfo di = new DirectoryInfo(folderToSearch);
FileInfo[] fi = di.GetFiles(“*.*”, SearchOption.AllDirectories);

//now the fi array instance contains full paths of all found files (let’s put filenames in a listbox):
lstFiles.Items.Clear();

foreach (FileInfo filinf in fi) {
    lstFiles.Items.Add(Path.GetFileName(filinf.FullName));
}