TdxChartCustomDiagram Class

The base class for all diagram classes.

Declaration

TdxChartCustomDiagram = class(
    TcxLockableComponent,
    IdxChartVisualElement,
    IdxChartCloneComponent,
    IdxChartDiagram
)

Remarks

A diagram is a pane designed to display and manage series in the Chart control. The TdxChartCustomDiagram class implements appearance and behavior settings common to all diagram classes.

VCL Chart Control: Series in XY Diagrams

Main API Members

The list below outlines key members of the TdxChartCustomDiagram class that allow you to configure diagrams and manage series in them.

Title: Specifies the diagram title, and its position and appearance.

SeriesCount | VisibleSeriesCount: Return the total number of series and the number of visible series in the diagram.
Series | VisibleSeries: Provide access to visible and hidden series by their indexes.

Appearance: Provides access to diagram appearance settings.
Index: Specifies the diagram’s index in the Chart control.
Visible: Specifies if the Chart control displays the diagram and its visible series.
Legend: Provides access to the diagram’s legend pane settings.

BeginUpdate | EndUpdate | CancelUpdate: Allow you to avoid excessive redraw operations during batch data and appearance setting changes.

DeleteAllSeries: Deletes all series in the diagram.

OnGetSeriesPointDrawParameters | OnGetValueLabelDrawParameters: Allow you to customize individual series points and value labels.
Assign: Copies compatible settings between diagrams.

Direct TdxChartCustomDiagram Class References and Terminal Descendants

A Chart control’s Diagrams and VisibleDiagrams properties reference created diagrams as TdxChartCustomDiagram objects. Cast them to the following descendants to access all diagram type-specific properties and methods:

TdxChartXYDiagram

A diagram designed to display series using the axis of arguments (X-axis) and the axis of values (Y-axis). An XY diagram can plot Area, Bar, and Line series.

VCL Chart Control: An XY Diagram Example with Area, Bar, and Line Series

TdxChartSimpleDiagram

A diagram intended to plot Pie and Doughnut series.

VCL Chart Control: A Simple Diagram Example with Pie and Doughnut Series

Example

The following code example creates an XY diagram with two Bar chart series and populates them with data in unbound mode:

Delphi
C++

uses cxDataStorage; // This unit declares the TcxStringValueType class
// ...
var
  AXYDiagram: TdxChartXYDiagram;
  AXYSeries: TdxChartXYSeries;
  ADataBinding: TdxChartXYSeriesUnboundDataBinding;
begin
  dxChartControl1.BeginUpdate;  // Initiates the following batch change
  try
    AXYDiagram := dxChartControl1.AddDiagram<TdxChartXYDiagram>('DevAV Sales by Region');
    AXYDiagram.Title.Appearance.FontOptions.Size := 20;
    AXYDiagram.Axes.AxisY.Title.Text := 'Millions of Dollars';
    AXYSeries := AXYDiagram.AddSeries('2018');  // Creates a new XY series with the caption "2018"
    AXYSeries.DataBindingClass := TdxChartXYSeriesUnboundDataBinding;  // Selects the unbound data access mode
    ADataBinding := AXYSeries.DataBinding as TdxChartXYSeriesUnboundDataBinding;
    ADataBinding.ArgumentField.ValueTypeClass := TcxStringValueType;  // Selects the string data type
    AXYSeries.ViewClass := TdxChartXYSeriesBarView;  // Selects the Bar series View
    AXYSeries.Points.Add('Asia', 4.2372);
    AXYSeries.Points.Add('Australia', 1.7871);
    AXYSeries.Points.Add('Europe', 3.0884);
    AXYSeries.Points.Add('North America', 3.4855);
    AXYSeries.Points.Add('South America', 1.6027);
    AXYSeries.View.ValueLabels.Visible := True;  // Displays value labels on bars
    AXYSeries := AXYDiagram.AddSeries('2019');  // Creates a new XY series with the caption "2019"
    AXYSeries.DataBindingClass := TdxChartXYSeriesUnboundDataBinding;  // Selects the unbound data access mode
    ADataBinding := AXYSeries.DataBinding as TdxChartXYSeriesUnboundDataBinding;
    ADataBinding.ArgumentField.ValueTypeClass := TcxStringValueType; // Selects the string data type
    AXYSeries.ViewClass := TdxChartXYSeriesBarView; // Selects the Bar series View
    AXYSeries.Points.Add('Asia', 4.7685);
    AXYSeries.Points.Add('Australia', 1.9576);
    AXYSeries.Points.Add('Europe', 3.3579);
    AXYSeries.Points.Add('North America', 3.7477);
    AXYSeries.Points.Add('South America', 1.8237);
    AXYSeries.View.ValueLabels.Visible := True;  // Displays value labels on bars
  finally
    dxChartControl1.EndUpdate;  // Calls EndUpdate regardless of the batch operation's success
  end;
end;

#include "cxDataStorage.hpp"  // This header declares the TcxStringValueType class
// ...
  TdxChartXYDiagram *AXYDiagram;
  TdxChartXYSeries *AXYSeries;
  TdxChartXYSeriesUnboundDataBinding *ADataBinding;
  // ...
  dxChartControl1->BeginUpdate();  // Initiates the following batch change
  try
  {
    AXYDiagram = new TdxChartXYDiagram(dxChartControl1->Owner);
    AXYDiagram->SetParentComponent(dxChartControl1);
    AXYDiagram->Title-Text = "DevAV Sales by Region";
    AXYDiagram->Title->Appearance->FontOptions->Size = 20;
    AXYDiagram->Axes->AxisY->Title->Text = "Millions of Dollars";
    AXYSeries = AXYDiagram->AddSeries("2018");  // Creates a new XY series with the caption "2018"
    // Selects the unbound data access mode
    AXYSeries->DataBindingClass = __classid(TdxChartXYSeriesUnboundDataBinding);
    AXYSeries->ViewClass = __classid(TdxChartXYSeriesBarView);  // Selects the Bar series View
    ADataBinding = dynamic_cast<TdxChartXYSeriesUnboundDataBinding*>(AXYSeries->DataBinding);
    // Selects the string data type for arguments
    ADataBinding->ArgumentField->ValueTypeClass = __classid(TcxStringValueType);
    AXYSeries->Points->Add("Asia", 4.2372);
    AXYSeries->Points->Add("Australia", 1.7871);
    AXYSeries->Points->Add("Europe", 3.0884);
    AXYSeries->Points->Add("North America", 3.4855);
    AXYSeries->Points->Add("South America", 1.6027);
    AXYSeries->View->ValueLabels->Visible = true; // Displays value labels on bars
    AXYSeries = AXYDiagram->AddSeries("2019");  // Creates a new XY series with the caption "2019"
    // Selects the unbound data access mode
    AXYSeries->DataBindingClass = __classid(TdxChartXYSeriesUnboundDataBinding);
    AXYSeries->ViewClass = __classid(TdxChartXYSeriesBarView);  // Selects the Bar series View
    ADataBinding = dynamic_cast<TdxChartXYSeriesUnboundDataBinding*>(AXYSeries->DataBinding);
    // Selects the string data type for arguments
    ADataBinding->ArgumentField->ValueTypeClass = __classid(TcxStringValueType);
    AXYSeries->Points->Add("Asia", 4.7685);
    AXYSeries->Points->Add("Australia", 1.9576);
    AXYSeries->Points->Add("Europe", 3.3579);
    AXYSeries->Points->Add("North America", 3.7477);
    AXYSeries->Points->Add("South America", 1.8237);
    AXYSeries->View->ValueLabels->Visible = true;  // Displays value labels on bars
  }
  __finally
  {
    dxChartControl1->EndUpdate();  // Calls EndUpdate regardless of the batch operation's success
  }
  // ...

VCL Chart Control: An XY Diagram Example with two Bar Series