How to create a function series graph

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            IAoInitialize ao = new AoInitializeClass();
            ao.Initialize(esriLicenseProductCode.esriLicenseProductCodeBasic);
            SampleFunctionSmoothing(@"path to your shapefile", "field name", @
                "path to your output image");
            ao.Shutdown();
        }

        static void SampleFunctionSmoothing(String pathToShapeFile, String
            seriesFieldName, String pathToOutImage)
        {

            // Open workspace for input shapefile.
            IWorkspaceFactory shapefileWorkspaceFactory = new
                ShapefileWorkspaceFactoryClass();
            IWorkspace shapefileWorkspace;
            shapefileWorkspace = shapefileWorkspaceFactory.OpenFromFile
                (System.IO.Path.GetDirectoryName(pathToShapeFile), 0);
            IFeatureWorkspace featureWorkspace = (IFeatureWorkspace)
                shapefileWorkspace;

            // Get table for input shapefile.
            ITable table = (ITable)featureWorkspace.OpenFeatureClass
                (System.IO.Path.GetFileNameWithoutExtension(pathToShapeFile));

            // Create data graph.
            IDataGraphT dataGraphT = new DataGraphTClass();

            // Add bar series.
            ISeriesProperties seriesProps = dataGraphT.AddSeries("bar:vertical");
            seriesProps.SourceData = table;
            seriesProps.SetField(1, seriesFieldName);

            // Add function series.
            ISeriesProperties funcSeriesProps = dataGraphT.AddSeries("ftSmoothing");

            // The only valid data source for the function series is another nonfunction series unique name.
            funcSeriesProps.SourceData = seriesProps.UniqueName;
            funcSeriesProps.CustomColor = 0x000000ff;

            // Set smoothing function-specific parameters.
            IFunctionSeriesProperties funcProps = (IFunctionSeriesProperties)
                funcSeriesProps;
            funcProps.set_Property("FACTOR", 4);
            funcProps.set_Property("LINE_PASSES_POINTS", true);

            // Update data graph.
            dataGraphT.Update(null);

            // Export graph to file (format depends on file extension).
            dataGraphT.ExportToFile(pathToOutImage);
        }
    }
}

Namespace ConsoleApplication1VBNET

Class Program
    Shared Sub Main(ByVal args() As String)
    Dim ao As IAoInitialize = New AoInitializeClass()
    ao.Initialize(esriLicenseProductCode.esriLicenseProductCodeBasic)
    SampleFunctionSmoothing("path to your shapefile", "field name", "path to your output image")
    ao.Shutdown()
End Sub

Shared Sub SampleFunctionSmoothing(ByVal pathToShapeFile As String, ByVal seriesFieldName As String, ByVal pathToOutImage As String)

' Open workspace for input shapefile.
Dim shapefileWorkspaceFactory As IWorkspaceFactory = New ShapefileWorkspaceFactoryClass()
Dim shapefileWorkspace As IWorkspace
shapefileWorkspace = shapefileWorkspaceFactory.OpenFromFile(System.IO.Path.GetDirectoryName(pathToShapeFile), 0)
Dim featureWorkspace As IFeatureWorkspace = CType(shapefileWorkspace, IFeatureWorkspace)

' Get table for input shapefile.
Dim table As ITable = CType(featureWorkspace.OpenFeatureClass(System.IO.Path.GetFileNameWithoutExtension(pathToShapeFile)), ITable)

' Create data graph.
Dim dataGraphT As IDataGraphT = New DataGraphTClass()

' Add bar series.
Dim seriesProps As ISeriesProperties = dataGraphT.AddSeries("bar:vertical")
seriesProps.SourceData = table
seriesProps.SetField(1, seriesFieldName)

' Add function series.
Dim funcSeriesProps As ISeriesProperties = dataGraphT.AddSeries("ftSmoothing")

' The only valid data source for the function series is another nonfunction series unique name.
funcSeriesProps.SourceData = seriesProps.UniqueName
funcSeriesProps.CustomColor = 110000

' Set smoothing function-specific parameters.
Dim funcProps As IFunctionSeriesProperties = CType(funcSeriesProps, IFunctionSeriesProperties)
funcProps.Property("FACTOR") = 4
funcProps.Property("LINE_PASSES_POINTS") = True

' Update data graph.
dataGraphT.Update(Nothing)

' Export graph to file (format depends on file extension).
dataGraphT.ExportToFile(pathToOutImage)
End Sub

End Class

End Namespace