/// <summary>压缩</summary>
/// <param name="di"></param>
/// <param name="destFile"></param>
public static void Compress(this DirectoryInfo di, String destFile = null)
{
if (destFile.IsNullOrEmpty())
{
destFile = di.Name + ".zip";
}
if (File.Exists(destFile))
{
File.Delete(destFile);
}
if (destFile.EndsWithIgnoreCase(".zip"))
#if NET4
{ ZipFile.CompressDirectory(di.FullName, destFile); }
#else
{ ZipFile.CreateFromDirectory(di.FullName, destFile, CompressionLevel.Optimal, true); }
