Remove Cache Data with Named Tags

Note

This feature is only available in NCache Enterprise Edition.

The items added with Named Tags to the cache can also be removed from the cache using the same named tag.

Similar to updating Named Tags; they can also be removed via CacheItem. CacheItem is a custom class provided by NCache which can be used to add data to the cache. In order to remove Named Tag via CacheItem the Named Tag property of the CacheItem is set as null.

Pre-Requisites

• Include the following namespace in your application:
  • Alachisoft.NCache.Client
  • Alachisoft.NCache.Runtime.Caching
  • Alachisoft.NCache.Runtime.Exceptions
• The application must be connected to cache before performing the operation.
• Cache must be running.
• Make sure that the data being added is serializable.
• To ensure the operation is fail safe, it is recommended to handle any potential exceptions within your application, as explained in Handling Failures.

The following example removes the Named Tags via CacheItem.

try
{
    // Pre-condition: Cache is already connected
    // CacheItem is already added in the cache with named tags with this key
    string key = "1001";

    // Retrieve the CacheItem using the key
    CacheItem cacheItem = cache.GetCacheItem(key);

    // Set the named tag property of the cacheItem as null
    cacheItem.NamedTags = null;

    // Re-insert the cacheItem in the cache with named tags removed
    cache.Insert(key, cacheItem);

    // CacheItem is successfully re-inserted in cache with removed named tags
}
catch (OperationFailedException ex)
{
    // Exception can occur due to:
    // Connection Failures 
    // Operation Timeout
    // Operation performed during state transfer
}
catch (Exception ex)
{
    // Any other generic exception like ArgumentNullException or ArgumentException
}

Recommendation: To ensure the operation is fail safe, it is recommended to handle any potential exceptions within your application, as explained in Handling Failures.

Note

cacheItem.NamedTags.Remove(tagName) method will remove the Named Tag associated with the tag name tagName. If all Named Tags are removed from the Named Tags dictionary and the cache item is then inserted into cache, Named Tags will be removed from that cache item since empty Named Tags dictionary indicates no Named Tags.

Additional Resources

NCache provides sample application for Tags at:

• GitHub
• Shipped with NCache: %NCHOME%\samples\dotnet\GroupsAndTags

See also

Add/Update Items with Tags
Retrieving Items with Tag
SQL Query with NamedTags
SQL Delete with NamedTags