SampledMetricDefinition pageMetricDefinition;
 
//since sampled metrics have only one value per metric, we have to create multiple metrics (one for every value)
if (SampledMetricDefinition.TryGetValue("GibraltarSample", "Database.Engine", "Cache Pages", out pageMetricDefinition) == false)
{
    //doesn't exist yet - add it in all of its glory.  This call is MT safe - we get back the object in cache even if registered on another thread.
    pageMetricDefinition = SampledMetricDefinition.Register("GibraltarSample", "Database.Engine", "cachePages", 
            SamplingType.RawCount, "Pages", "Cache Pages", "The number of pages in the cache");
}
 
//now that we know we have the definitions, make sure we've defined the metric instances.
SampledMetric pageMetric = SampledMetric.Register(pageMetricDefinition, null);
 
//now go ahead and write those samples....
pageMetric.WriteSample(pagesLoaded);

//Alternately, it can be done in a single line of code each, although somewhat less readable.  
//Note the WriteSample call after the Register call.
SampledMetric.Register("GibraltarSample", "Database.Engine", "cachePages", SamplingType.RawCount, 
    "Pages", "Cache Pages", "The number of pages in the cache", null).WriteSample(pagesLoaded);

//by using an object with the appropriate attributes we can do it in 
//one line - even though it writes multiple values.
SampledMetric.Write(new CacheSampledMetric(pagesLoaded));
 
//To use the above line, you have to define the following class:
 
/// <summary>
/// Log sampled metrics using a single object
/// </summary>
[SampledMetric("GibraltarSample", "Database.Engine")]
public class CacheSampledMetric
{
    public CacheSampledMetric(int pagesLoaded)
    {
        Pages = pagesLoaded;
        Size = pagesLoaded * 8192;
    }
 
    [SampledMetricValue("pages", SamplingType.RawCount, "Pages", Caption = "Pages in Cache", 
        Description = "Total number of pages in cache")]
    public int Pages { get; private set; }
 
    [SampledMetricValue("size", SamplingType.RawCount, "Bytes", Caption = "Cache Size", 
        Description = "Total number of bytes used by pages in cache")]
    public int Size { get; private set; }
}