Creating Interactive Dashboards Using TeeChart Pro ActiveXInteractive dashboards let users explore data visually, spot trends quickly, and make decisions faster. TeeChart Pro ActiveX is a powerful charting component for Windows applications (especially Visual Basic, VBA, Delphi, and C++ Builder) that provides a wide range of chart types, rich customization, and interactive features ideal for dashboard development. This article walks through planning, building, and enhancing interactive dashboards with TeeChart Pro ActiveX, including code examples, UI/UX tips, and performance considerations.
Why choose TeeChart Pro ActiveX for dashboards
- Wide variety of chart types: line, bar, pie, area, Gantt, financial, radar, surface, contour, and many more.
- Interactivity built-in: zooming, panning, cursor tools, tooltips, legends, click events, and live data updates.
- Custom drawing and annotations: labels, shapes, layers, and custom series renderers.
- Compatibility: integrates well with Visual Basic, VBA (Excel/Access), Delphi, and C++ Builder.
- Performance: optimized drawing routines and data handling for large datasets.
Planning your dashboard
Good dashboards start with clear goals and user-focused design.
- Define purpose and audience
- Operational dashboards (real-time monitoring) need rapid updates and simple visuals.
- Analytical dashboards (exploratory analysis) benefit from richer controls and multiple linked views.
- Select key metrics (KPIs)
- Limit to the most actionable metrics; provide drill-down where needed.
- Layout and visual hierarchy
- Place high-priority metrics at top-left / top-center. Use larger charts for primary KPIs and smaller widgets for secondary info.
- Interaction patterns
- Filtering, brushing (selecting data in one chart to highlight in others), drill-down on click, time range selection, and hover tooltips.
- Data flow and refresh cadence
- Decide between real-time streaming, periodic polling, or manual refresh. Consider caching and aggregation to reduce load.
Setting up TeeChart Pro ActiveX
- Install TeeChart Pro ActiveX following vendor instructions and register the OCX on your development machine.
- Add the control to your IDE toolbox (for VB6 or Delphi) or reference the ActiveX in your project.
- Create a form/window and drop TeeChart ActiveX controls where charts will appear. You can use multiple TChart controls or a single chart with multiple panels/series.
Example (Visual Basic 6) — placing a TChart on a form:
' Place a TChart control named TChart1 on the form via the toolbox. Private Sub Form_Load() TChart1.Series.Add ' default series TChart1.Title.Text = "Sample Dashboard Chart" End Sub Building the dashboard: charts & widgets
- Use appropriate chart types: time series for trends, bar for comparisons, pie for parts-of-a-whole (sparingly), scatter for relationships, Gantt for schedules, and heatmaps/contour for density.
- Combine series types on a single chart when it clarifies the data (e.g., line + bar for actual vs. target).
- Use gauges or numeric indicators for single-value KPIs. TeeChart supports custom drawing for such widgets.
Example: adding two series (line + bar) in VB6:
Dim sLine As Series Dim sBar As Series Set sLine = TChart1.Series.Add() sLine.Type = ctLine sLine.AddXY 1, 10 sLine.AddXY 2, 15 Set sBar = TChart1.Series.Add() sBar.Type = ctBar sBar.AddXY 1, 8 sBar.AddXY 2, 12 Interactivity features
- Zooming & panning
- Enable mouse wheel and drag-to-zoom. Configure axes to auto-scale or preserve user zoom.
- Cursors and crosshairs
- Use cursors to display precise values; synchronize cursors across charts for linked inspection.
- Tooltips and labels
- Show contextual information on hover. Customize content to include computed metrics.
- Click & drill-down events
- Capture click events on series or points to open detail views or filter other charts.
- Brushing & linked charts
- When the user selects a range or a set of points in one chart, highlight corresponding points in other charts. Implement by handling selection events and applying highlight styles to matching series points.
- Live updates
- Append data points and refresh the chart efficiently. Use buffering or update-suspension features to avoid flicker when adding many points.
Example: handle OnClickSeries (VB6 pseudocode):
Private Sub TChart1_OnSeriesClick(ByVal SeriesIndex As Integer, ByVal ValueIndex As Integer) Dim xVal As Double, yVal As Double xVal = TChart1.Series(SeriesIndex).XValue(ValueIndex) yVal = TChart1.Series(SeriesIndex).YValue(ValueIndex) ' Open detail form or filter other charts based on xVal End Sub UI/UX best practices
- Keep visuals simple and consistent: color palette, fonts, and spacing.
- Use color meaningfully: reserve bright colors for highlights and alerts; ensure sufficient contrast.
- Provide clear legends and axis labels; avoid overloading charts with text.
- Support accessibility: keyboard navigation for interactions and high-contrast modes.
- Mobile/resize behavior: design charts to reflow or offer alternate simplified views for small screens.
Performance optimization
- Aggregate data before plotting when possible (rollups, sampling).
- Use faster series types for large datasets (e.g., FastLine) and avoid per-point heavy formatting.
- Batch updates: suspend repaint while adding many points, then refresh once.
- Limit event handlers that do expensive work on every redraw.
- Clip or throttle live update frequency (e.g., update UI at 10 Hz max).
Example: batch add with refresh suspension (conceptual):
TChart1.Suspended = True ' add many points... TChart1.Suspended = False TChart1.Repaint Customizing appearance & annotations
- Use annotations for callouts and explanations; programmatically add text or shapes to emphasize anomalies.
- Custom paint hooks allow drawing overlays (threshold lines, forecast bands).
- Use gradient fills, transparency, and pens to improve aesthetics while keeping readability.
Example: draw a horizontal threshold line (VB6 pseudocode):
With TChart1.Axes.Left .CalcYPos(ThresholdValue) ' pseudo-method to get screen Y End With TChart1.Canvas.Pen.Color = vbRed TChart1.Canvas.Line (LeftX, YPos)-(RightX, YPos) Data connectivity and refreshing
- Connect to databases (ODBC, ADO) or APIs to fetch data. Use parameterized queries for filtering and pagination.
- For real-time, use message queues, sockets, or polling. Ensure thread-safe updates if data arrives on background threads—marshal updates back to the UI thread.
- Implement change detection to update only affected series/points.
Example: updating chart from a timer-based poll:
Private Sub Timer1_Timer() ' Fetch new data ' Append or update series TChart1.Refresh End Sub Testing, monitoring, and maintenance
- Test with realistic data volumes and update rates.
- Monitor memory usage and CPU during heavy updates.
- Provide logging around data loading and interaction events for debugging.
- Version control chart templates and styles to standardize dashboard look-and-feel.
Example dashboard architecture
- Data layer: ETL/aggregation, caching, time-series DB or relational DB.
- API/service layer: exposes endpoints for filtered or aggregated data.
- Presentation layer: desktop app embedding TeeChart ActiveX controls, UI components for filters/controls, background worker for data refresh.
- Persistence: user preferences for layout, saved filters, and snapshots.
Troubleshooting common issues
- Registration problems: ensure the OCX is registered with regsvr32 and the right bitness (32-bit vs 64-bit) matches your app.
- Flicker on updates: batch updates and suspend painting.
- Slow rendering: switch to FastLine or reduce point count via sampling.
- Event threading: marshal cross-thread calls to the UI thread to avoid crashes.
Conclusion
TeeChart Pro ActiveX provides a robust feature set for building interactive, high-performance dashboards in Windows desktop applications. Focus on clear goals, appropriate chart choices, thoughtful interactivity, and careful performance tuning to deliver dashboards that help users explore data and act faster.
Leave a Reply