Question

Scenario: I am tracking several performance counters and have a CounterDescription[] correlate to DataSnapshot[]… where CounterDescription[n] describes the data loaded within DataSnapshot[n].

I want to expose an easy to use API within C# that will allow for the easy and efficient expansion of the arrays.

Simplified example (it gets more complex)

CounterDescription[0] = Humidity;
DataSnapshot[0] = .9;
CounterDescription[1] = Temp;
DataSnapshot[1] = 63;

Note how my intent is to correlate many Datasnapshots with a DateTime reference, and using the offset of the data to refer to its meaning. This was determined to be the most efficient way to store the data on the back-end, and has now reflected itself into the following structure:

  public class myDataObject { 
    [DataMember]
    public SortedDictionary<DateTime, float[]> Pages { get; set; }

    /// <summary>
    /// An array that identifies what each position in the array is supposed to be
    /// </summary>
    [DataMember]
    public CounterDescription[] Counters { get; set; }
   }

How will myDataObject be used?:

I will frequently search for a counter by string name, and use its’ position to determine what offset a particular value will be saved. I can use an homegrown extension method to enumerate the object, or leverage the framework if ordering is guaranteed.

Also, I will need to expand each of these arrays as new sensors are added: (float[] and CounterDescription[] ), but whatever data already exists must stay in that relative offset. I don’t want the serialized version of this object to confuse Temp (offset 1) with Humidity (offset 0)

Which .NET objects support this fixed ordering, expansion, and enumeration (and optional searching by string)? My guess is to use one of these objects…

Array[] , LinkedList<t>, and List<t>

Answer 1

Use a Dictionary<string, double> so that each name (string) maps to a value (double):

var counters = new Dictionary<string, double>();

counters["Humidity"] = 0.9;
counters["Temp"] = 63;

And use a service that gets and sets the counter values:

[OperationContract]
public double GetCounter(string name)
{
     return Counters[name];
}

[OperationContract]
public void SetCounter(string name, double value)
{
     Counters[name] = value;
}

You can use your CounterDescription and/or DataSnapshot classes in the same way, but make sure that the class you use as the key (probably CounterDescription) overrides Object.Equals() and Object.GetHashCode() with a proper implementation.