TdxChartXYSeriesDBDataBinding Class
Stores data binding settings for an XY series in bound data access mode.
Declaration
TdxChartXYSeriesDBDataBinding = class(
TdxChartSeriesDBDataBinding
)
Remarks
An XY series is in bound mode when its DataBindingType property is set to 'DB'
. In this mode, you can use the DataSource property to bind the series to data. The ArgumentField and ValueField properties specify source fields in the underlying dataset for arguments and values, respectively.
The DataBinding property of an XY series references the TdxChartXYSeriesDBDataBinding
class as a TdxChartSeriesCustomDataBinding object if the DataBindingType property of the series is set to 'DB'
.
Note
You need to cast the DataBinding property value to the TdxChartXYSeriesDBDataBinding
class to access the DataSource, ArgumentField, and ValueField properties.
Code Example
The following code example creates three line series with identical appearance settings in bound mode:
var
AXYDiagram: TdxChartXYDiagram;
AXYSeriesAmericas, AXYSeriesEurope, AXYSeriesAfrica: TdxChartXYSeries;
ALineView: TdxChartXYSeriesLineView;
ADataBinding: TdxChartXYSeriesDBDataBinding;
begin
dxChartControl1.BeginUpdate; // Initiates the following batch change
try
dxChartControl1.Titles.Add.Text := 'Historic, Current, and Future Population Projection';
AXYDiagram := dxChartControl1.AddDiagram<TdxChartXYDiagram>;
AXYDiagram.Axes.AxisY.Title.Text := 'Population mid-year, millions';
AXYDiagram.Axes.AxisX.Interlaced := True;
AXYSeriesEurope := AXYDiagram.AddSeries('Europe'); // Creates a new series with the caption "Europe"
AXYSeriesEurope.ShowInLegend := TdxChartSeriesShowInLegend.Diagram;
AXYSeriesEurope.DataBindingClass := TdxChartXYSeriesDBDataBinding;
ADataBinding := AXYSeriesEurope.DataBinding as TdxChartXYSeriesDBDataBinding;
ADataBinding.DataSource := dsPopulation; // Assigns a data source
ADataBinding.DataSource.DataSet := mdPopulation; // Assigns a dataset
ADataBinding.DataSource.DataSet.Active := True; // Enables the assigned dataset
ADataBinding.ArgumentField.FieldName := 'Year'; // Specifies the source dataset field for arguments
ADataBinding.ValueField.FieldName := 'Europe'; // Specifies the source dataset field for values
AXYSeriesEurope.ViewClass := TdxChartXYSeriesLineView; // Selects the Line series View
ALineView := AXYSeriesEurope.View as TdxChartXYSeriesLineView;
ALineView.Markers.Visible := True; // Displays value markers
ALineView.ValueLabels.Visible := True; // Displays value labels
ALineView.Appearance.StrokeOptions.Width := 2; // Increases line width
AXYSeriesAmericas := AXYDiagram.AddSeries; // Creates a new series with the default settings
AXYSeriesAmericas.AssignFrom(AXYSeriesEurope); // Copies all settings from the "Europe" series
AXYSeriesAmericas.Caption := 'Americas'; // Defines a different series caption
// Specifies a different source dataset field for values
ADataBinding := AXYSeriesAmericas.DataBinding as TdxChartXYSeriesDBDataBinding;
ADataBinding.ValueField.FieldName := 'Americas';
AXYSeriesAfrica := AXYDiagram.AddSeries; // Creates a new series with the default settings
AXYSeriesAfrica.AssignFrom(AXYSeriesEurope); // Copies all settings from the "Europe" series
AXYSeriesAfrica.Caption := 'Africa'; // Defines a different series caption
// Specifies a different source dataset field for values
ADataBinding := AXYSeriesAfrica.DataBinding as TdxChartXYSeriesDBDataBinding;
ADataBinding.ValueField.FieldName := 'Africa';
finally
dxChartControl1.EndUpdate; // Calls EndUpdate regardless of the batch operation's success
end;
end;