Checking if key exists in cache

This API request checks if an object exists in cache. If object is present in cache, the method returns true, otherwise - false. All methods are available via Backendless.Cache.[methodname] accessor:

// synchronous method
public Boolean Contains( String key )

// asynchronous method
public void Contains( String key, AsyncCallback<Boolean> callback )

where:

Argument	Description
key	identifies the object to check in cache.
callback	the callback used for asynchronous calls to deliver result or fault to the calling program

Example

AsyncCallback<Boolean> callback = new AsyncCallback<Boolean>(
result =>
{
  System.Console.WriteLine( "[ASYNC] object exists in cache - "  + result );
},
fault =>
{
  System.Console.WriteLine( "Error - " + fault );
} );

// get object from cache asynchronously
Backendless.Cache.Contains( "firstorder", callback );

// get object from cache synchronously
Boolean objectExists = Backendless.Cache.Contains( "firstorder" );
System.Console.WriteLine( "[SYNC] object exists in cache - "  + objectExists );