Public Overloads Sub FilterTopN( _
   ByVal pointCount As Integer, _
   ByVal inputSeriesNames As String, _
   ByVal outputSeriesNames As String _
) 

Visual Basic (Usage)	Copy Code
Dim instance As DataManipulator Dim pointCount As Integer Dim inputSeriesNames As String Dim outputSeriesNames As String   instance.FilterTopN(pointCount, inputSeriesNames, outputSeriesNames)

public void FilterTopN( 
   int pointCount,
   string inputSeriesNames,
   string outputSeriesNames
)

Parameters

pointCount

The number of data points that the filtering operation will not remove (or mark as empty).
Number of top/bottom points to return.

inputSeriesNames

The name(s) of the series that will be filtered. For multiple series use a comma-separated list of names, and make sure that the series are aligned. An asterisk (*) may be used to filter all series in the series collection (in which case the outputSeriesName parameter must be empty).
Comma separated input series names.

outputSeriesNames

The name(s) of the series that store the filtered data. Make sure that the number of output series matches the number of input series, otherwise an exception will be thrown.
Comma separated output series names.

This method filters all data points from one or more series except for a specified number of points. The points that aren't filtered correspond to points in the first series that have the largest first Y-values. For example, this method can be used to retrieve the top five products by sales.

Filtering should only be applied to multiple series that are aligned, otherwise an exception will be thrown (for information concerning alignment of data see the Aligning Data topic). Note also that multiple series are filtered using the values from the FIRST specified series. If two series must be filtered independently call the FilterTopN method twice using one series as a parameter.

IMPORTANT: the output series that stores the filtered data from the first input series will have its data points sorted by the first Y-value. Since all output series are aligned this means that the data in each output series is ordered according to the sorting of the first output series.

Filters are always applied to an entire series.

Filtered points can be either removed from a series (default) or displayed as empty points, depending on the FilterSetEmptyPoints value.

To filter a series:

• and keep data points with the smallest values use another definition of this function that uses a getTopValues argument.
• based on a data point value other than the first Y-value (e.g. "X", "Y2", "Y3", etc.) use another definition of this method that takes a usingValue argument.

If a specified output series has not been created and added to the SeriesCollection when this function call is made it will be created and added to the collection automatically, and have default Series properties (e.g. column chart type, etc.). In addition, the ChartArea property of the series is set to "Default", and if a chart area with the name "Default" exists in the ChartAreasCollection it will be used to draw the chart. If there is no chart area with this name the first ChartArea object in the collection will be used to display the series.

Target Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family, Windows Vista, Windows Server 2008 family

Reference