public CloudFile(ICloudFile file, IFolder folder)
: base(Path.Combine(folder.FullPath, file.CloudId), folder)
{
if (file.IsNull() || folder.IsNull())
{
throw new ArgumentNullException();
}
this.CloudItem = file;
this.Parent = folder;
this.Name = file.Name;
this.Extension = Path.GetExtension(file.Name);
this.LastModifyTime = file.ModificationTime;
this.Size = file.Size;
this.FullPath = Path.Combine(folder.FullPath, file.CloudId);
}