Use Linq to filter Hashtable based on a property of Values custom object

Question

I have a synchronized Hashtable with int as the key, and a custom class called "Job" as the value. I would like to filter this Hashtable based on a property in my Job class called "JobSize". JobSize is just an enum with values Small, Medium, and Large.

It's fine if it needs to be converted to another collection type to do this.

I know there's a slick LINQy way to do this, but I haven't found it yet...

Answer 1

You should be able to use something like this:

IEnumerable<Job> smallJobs
  = hashTable.Values.Cast<Job>.Where(job => job.JobSize == JobSize.Small);

Answer 2

It looks like this will work for me:

var smallJobs = hashTable.Values.Cast<Job>().Where(job => job.JobSize == JobSize.Small);

The ".Cast<Job>()" is required because Hashtable is non-generic.

Answer 3

Do you need to maintain the keys and values in your filtered Hashtable? If so, try this.

It'll filter the Hashtable and return the filtered results as a strongly typed Dictionary<int,Job>:

var filtered = yourHashtable.Cast<DictionaryEntry>()
                            .Where(x => ((Job)x.Value).JobSize == JobSize.Small)
                            .ToDictionary(x => (int)x.Key, x => (Job)x.Value);