Example 44: Trend lines in XY charts
This sample will plot a
X/Y (scatter) chart and a trend line.
You may also obtain the
equation factors for the trend line calling
CalculationTrendLine property which will
return a TrendLine object containing the
values of the formula y = bx + a.
Steps to run this sample:
1. Create a new Windows
application project (VB.NET)
2. Add Super 2d/3d Graph
Library to the toolbox pallete and drag a
chart
to Form1.
3. Add a Label
control below the chart control.
4. Copy and paste de
following code:
Form Code
Imports
Super2d3dGraphLibrary
Public
Class
Form1
Private
Sub
Form1_Load(ByVal
sender
As
System.Object,
ByVal e
As
System.EventArgs)
Handles
MyBase.Load
Dim sf
As
New
SeriesFactory
sf.AddPoint(1, 2)
sf.AddPoint(1.7,
4)
sf.AddPoint(4.2,
6)
sf.AddPoint(5, 8)
sf.AddPoint(6, 10)
sf.AddPoint(8.2,
12)
With
Super2d3dGraph1
' Initial setup: license, title and chart
style
.LicenseeIdentifier =
"PROF"
.Title =
"Trend Line Sample"
.Style = STYLE2D3D.STYLE2D_XY
' Assign data
.Series = sf.Series
.ShowValues =
False
' Setup y-axis
.YAxisScaleMode =
SCALEMODE.SCALEMODE_FIXED
.YAxisScaleMinimum
= 0
.YAxisScaleMaximum = 14
.YAxisNumericFormat =
"0"
' Setup x-axis
.XAxisScaleMode =
SCALEMODE.SCALEMODE_FIXED
.XAxisScaleMinimum
= 0
.XAxisScaleMaximum = 10
.XAxisNumericFormat =
"0"
.ShowDividersX =
True
.ShowXAxis =
True
' Look and feel
.WallsBackStyle =
STYLEWALLBACKGROUND.STYLEWALLBACKGROUND_GRADIENT
.WallsBackColorPrincipal
= Color.LightGray
.WallsBackColorSecondary = Color.LightGray
.SeriesColor =
New
Color() {Color.Black}
.ShowDataTable =
False
.ShowLegend =
False
' Draw trend line
.Calculation =
CALCULATION.CALCULATION_AVERAGE
.CalculationLineStyle =
New
Pen(Color.Blue, 2)
' Refresh chart
.RefreshChart()
' Print trend line equation below chart
Dim
trendLine
As
Trendline = .CalculationTrendLine(0)
Label1.Text =
"Equation: y = "
& trendLine.b &
" x + "
& trendLine.a
End
With
End
Sub
End
Class
Result:
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