/// <summary>
/// Insert all metadata items from the data store for the specified media object. Assumes no existing metadata record exists
/// that matches the MediaObjectMetadataId value of each metadata item. Each metadata item is inserted and the newly
/// assigned MediaObjectMetadataId value is assigned to the item's MediaObjectMetadataId property.
/// </summary>
/// <param name="mediaObject">The media object for which to insert all metadata items to the data store.</param>
/// <param name="ctx">A database context.</param>
private static void InsertMetadataItems(IGalleryObject mediaObject, GspContext ctx)
{
// Insert meta data items, if any, into MediaObjectMetadata table.
if (mediaObject.MetadataItems.Count > 0)
{
foreach (IGalleryObjectMetadataItem metaDataItem in mediaObject.MetadataItems)
{
MediaObjectMetadataDto mDto = new MediaObjectMetadataDto
{
FKMediaObjectId = mediaObject.Id,
MetadataNameIdentifier = (int)metaDataItem.MetadataItemName,
Description = metaDataItem.Description,
Value = metaDataItem.Value
};
ctx.MediaObjectMetadatas.Add(mDto);
// Note: The newly assigned ID is not assigned back to metaDataItem.MediaObjectMetadataId, but that should be
// OK because we'll be reloading the items from the DB after the save.
}
}
}
/// <summary>
/// Persist each each metadata item that has HasChanges = true to the data store. If all items are marked for updating
/// (mediaObject.RegenerateMetadataOnSave = true), then all metadata items are deleted from the data store and then inserted based
/// on the current metadata items. If one or more items has HasChanges = false, then each item with HasChanges = true is
/// processed according to the following rules: (1) If the metadata value is null or an empty string, it is deleted from the
/// data store and removed from the MetadataItems collection. (2) If the item's MediaObjectMetadataId = int.MinValue, the
/// item is assumed to be new and is inserted. (3) Any item not falling into the previous two categories, but HasChanges = true,
/// is assumed to be pre-existing and an update stored procedure is executed.
/// </summary>
/// <param name="mediaObject">The media object for which to update metadata items in the data store.</param>
/// <param name="ctx">A database context.</param>
private static void UpdateMetadataItems(IGalleryObject mediaObject, GspContext ctx)
{
if (mediaObject.ExtractMetadataOnSave)
{
// User wants to replace all metadata items. Delete them all from the data store, then insert the ones we have.
DeleteMetadataItems(mediaObject, ctx);
InsertMetadataItems(mediaObject, ctx);
}
else
{
IGalleryObjectMetadataItemCollection metadataItemsToSave = mediaObject.MetadataItems.GetItemsToSave();
if (metadataItemsToSave.Count == 0)
{
return; // Nothing to save
}
// There is at least one item to persist to the data store.
foreach (IGalleryObjectMetadataItem metaDataItem in metadataItemsToSave)
{
if (String.IsNullOrEmpty(metaDataItem.Value))
{
// There is no value, so let's delete this item.
DeleteMetadataItem(metaDataItem, ctx);
// Remove it from the collection.
mediaObject.MetadataItems.Remove(metaDataItem);
}
else if (metaDataItem.MediaObjectMetadataId == int.MinValue)
{
// Insert the item.
MediaObjectMetadataDto mDto = new MediaObjectMetadataDto
{
FKMediaObjectId = mediaObject.Id,
MetadataNameIdentifier = (int)metaDataItem.MetadataItemName,
Description = metaDataItem.Description,
Value = metaDataItem.Value
};
ctx.MediaObjectMetadatas.Add(mDto);
// Note: The newly assigned ID is not assigned back to metaDataItem.MediaObjectMetadataId, but that should be
// OK because we'll be reloading the items from the DB after the save.
}
else
{
// Update the item.
MediaObjectMetadataDto mDto = ctx.MediaObjectMetadatas.Find(metaDataItem.MediaObjectMetadataId);
if (mDto != null)
{
mDto.MetadataNameIdentifier = (int)metaDataItem.MetadataItemName;
mDto.Description = metaDataItem.Description;
mDto.Value = metaDataItem.Value;
}
}
}
}
}
/// <summary>
/// Insert all metadata items from the data store for the specified media object. Assumes no existing metadata record exists
/// that matches the MediaObjectMetadataId value of each metadata item. Each metadata item is inserted and the newly
/// assigned MediaObjectMetadataId value is assigned to the item's MediaObjectMetadataId property.
/// </summary>
/// <param name="mediaObject">The media object for which to insert all metadata items to the data store.</param>
/// <param name="ctx">A database context.</param>
private static void InsertMetadataItems(IGalleryObject mediaObject, GspContext ctx)
{
// Insert meta data items, if any, into MediaObjectMetadata table.
if (mediaObject.MetadataItems.Count > 0)
{
int tmpId = 0;
var mDtos = new Dictionary<int, MediaObjectMetadataDto>();
var metas = new Dictionary<int, IGalleryObjectMetadataItem>();
foreach (IGalleryObjectMetadataItem metaDataItem in mediaObject.MetadataItems)
{
MediaObjectMetadataDto mDto = new MediaObjectMetadataDto
{
FKMediaObjectId = mediaObject.Id,
MetadataNameIdentifier = (int)metaDataItem.MetadataItemName,
Description = metaDataItem.Description,
Value = metaDataItem.Value
};
ctx.MediaObjectMetadatas.Add(mDto);
metas.Add(++tmpId, metaDataItem);
mDtos.Add(tmpId, mDto);
}
ctx.SaveChanges();
// Loop through each metadata item again, find the matching DTO object, and update
// the newly assigned ID.
foreach (KeyValuePair<int, IGalleryObjectMetadataItem> kvp in metas)
{
MediaObjectMetadataDto mDto;
if (mDtos.TryGetValue(kvp.Key, out mDto))
{
kvp.Value.MediaObjectMetadataId = mDto.MediaObjectMetadataId;
}
}
}
}
