[Parameter]
public string Height { get; set; }

<DxSparkline Data="@DataSource"
             Type="SparklineType.Bar"
             ArgumentFieldName="Month"
             ValueFieldName="VisitorCount"
             Height="10%"
             Width="200px" />

@code {
    IEnumerable<SparklineDataPoint> DataSource = Enumerable.Empty<SparklineDataPoint>();
    protected override void OnInitialized() {
        DataSource = GenerateData();
    }
}

public List<SparklineDataPoint> GenerateData() {
    return new List<SparklineDataPoint>() {
        new SparklineDataPoint( 01, 2210),
        new SparklineDataPoint( 02, 2103),
        new SparklineDataPoint( 03, 2132),
        new SparklineDataPoint( 04, 2000),
        new SparklineDataPoint( 05, -2062),
        new SparklineDataPoint( 06, 1954),
        new SparklineDataPoint( 07, 2112),
        new SparklineDataPoint( 08, 1967),
        new SparklineDataPoint( 09, -2009),
        new SparklineDataPoint( 10, 2087),
        new SparklineDataPoint( 11, 2112),
        new SparklineDataPoint( 12, 2038),
    };
}
public class SparklineDataPoint {
    public int Month { get; set; }
    public int VisitorCount { get; set; }
    public SparklineDataPoint(int month, int visitorCount) {
        Month = month;
        VisitorCount = visitorCount;
    }
}