Hash Table

The internal workings of the Hashtable class are complicated and, rather than repeat it all here, I'd suggest you read the Remarks section in the MSDN docs for this class:

http://msdn.microsoft.com/en-us/library/system.collections.hashtable.aspx

An important point to note is that all keys and values are stored internally as type System.Object.

This means that value types (int, double, char etc) need to be 'boxed' when they are stored and 'unboxed' (using a cast) when they are retrieved which degrades performance.

The Dictionary class doesn't have this problem because all keys and values are stored internally as their actual types and should therefore be preferred over Hashtable on performance grounds.

2 Replies

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ntokozo ngema13y ago
@Vulpes
Thank you very much.....very appreciated
0
Vulpes13y ago
The internal workings of the Hashtable class are complicated and, rather than repeat it all here, I'd suggest you read the Remarks section in the MSDN docs for this class:

http://msdn.microsoft.com/en-us/library/system.collections.hashtable.aspx

An important point to note is that all keys and values are stored internally as type System.Object.

This means that value types (int, double, char etc) need to be 'boxed' when they are stored and 'unboxed' (using a cast) when they are retrieved which degrades performance.

The Dictionary class doesn't have this problem because all keys and values are stored internally as their actual types and should therefore be preferred over Hashtable on performance grounds.
0