Mouse Interaction: Coordinate Tracking & Hotspots — WinForms

ProEssentials v10 WinForms .NET 8 — a dual-Y-axis Pego chart that combines two complementary mouse-interaction techniques: a ConvPixelToGraph tooltip showing both Y-axis values at the cursor, and a GetHotSpot status bar that names the chart element under the cursor (data point, series legend, or point label). Direct2D.

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What This Demonstrates

• Technique 1 — ConvPixelToGraph tooltip (Example 007): the PeCustomTrackingDataText event converts the mouse pixel position to graph coordinates, called twice (left Y and right Y) to show both axis values at the cursor, interpolated continuously between data points.
• Technique 2 — GetHotSpot status bar (Example 014): MouseMove calls GetHotSpot() to identify the named element under the cursor; when not over a named element, SearchSubsetPointIndex reports the nearest data point.
• Dual Y axis via RYAxisComparisonSubsets = 1 — three regional sales series on the left Y, market-share percentage on the right Y.
• Code-built UI — the form (status bar + chart) is constructed entirely in C#; no .Designer.cs, no .resx, so the WinForms designer is never invoked.

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WinForms vs WPF

This is the WinForms sibling of the WPF Mouse Interaction example. The ProEssentials chart configuration is identical between the two. The only differences are the host shell (WinForms Panel status bar + docked chart vs WPF Grid) and the geometry types in the mouse handlers: WPF's System.Windows.Point / Rect become System.Drawing.Point / Rectangle on the WinForms control (integer coordinates, no casts needed). GetHotSpot, ConvPixelToGraph, and SearchSubsetPointIndex are chart-object members and are unchanged.

➡️ WPF version: wpf-chart-mouse-interaction-hotspots-coordinate-tracking-proessentials

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Prerequisites

• Visual Studio 2022
• .NET 8 SDK (Windows)
• Internet connection for NuGet restore
• x64

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How to Run

1. Clone this repository
2. Open MouseInteractionHotspots.sln in Visual Studio 2022
3. Build → Rebuild Solution (restores the NuGet package automatically)
4. Press F5
5. Move the mouse over the chart — watch the tooltip show both Y values and the status bar name the element under the cursor. Left-drag to zoom; right-click for the context menu.

Designer note: This project has no .Designer.cs by design — the UI is built in code in MainForm.cs, avoiding native-control designer issues.

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NuGet Package

References ProEssentials.Chart.Net80.x64.Winforms from nuget.org. Package restore happens automatically on build.

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License

Example code is MIT licensed. ProEssentials requires a commercial license for continued use.