public void RemoveTags(string photoId, Tag[] tags)
{
var context = new PhotoAlbumDataContext();
foreach (var tag in tags)
{
var photoTag = new PhotoTagRow(photoId, tag.Name);
context.AttachTo(PhotoAlbumDataContext.PhotoTagTable, photoTag, "*");
context.DeleteObject(photoTag);
}
try
{
// continue trying to delete, even if not found
context.SaveChanges(SaveChangesOptions.ContinueOnError);
}
catch (DataServiceRequestException ex)
{
foreach (var resp in ex.Response)
{
// to be more robust, we will ignore 404 errors when
// the entity might have already been deleted (due to an
// incomplete operation earliet).
if (resp.StatusCode != (int)HttpStatusCode.NotFound
&& resp.StatusCode != (int)HttpStatusCode.OK)
{
throw;
}
}
}
}
public void CreateTags(string photoId, Tag[] tags)
{
var context = new PhotoAlbumDataContext();
foreach (var tag in tags)
{
// add the tag and associate to a picture for later searching
context.AddObject(PhotoAlbumDataContext.TagTable, new TagRow(tag));
context.AddObject(PhotoAlbumDataContext.PhotoTagTable, new PhotoTagRow(photoId, tag.Name));
}
try
{
// we want to continue - even if conflict is detected...
context.SaveChanges(SaveChangesOptions.ContinueOnError);
}
catch (DataServiceRequestException ex)
{
foreach (var resp in ex.Response)
{
// we might get a conflict here, which is ok (tag exists)
// the alternative is to query everytime to see if the tag
// exists, which is less efficient that just trying and
// handling exception.
if (resp.StatusCode != (int)HttpStatusCode.Conflict
&& resp.StatusCode != (int)HttpStatusCode.Created)
{
throw;
}
}
}
}