c# - 缩放时获取一组数据点

Question

我有一个带有 Series (SeriesChartType.Point) 的 MSChart 对象；启用缩放以允许用户放大数据的特定区域。在用户放大该区域后，我有兴趣了解仍然可见的数据点集。

有没有办法确定哪些数据点仍然可见？

Answer 1

类似下面的内容应该适合您。我用 Line ChartType 测试了它，但只要数据是 X,Y(而不是 X,Y,Y)

    Dim Xmin As Double = aChart.ChartAreas(0).AxisX.ScaleView.ViewMinimum
    Dim Xmax As Double = aChart.ChartAreas(0).AxisX.ScaleView.ViewMaximum

    Dim Ymin As Double = aChart.ChartAreas(0).AxisY.ScaleView.ViewMinimum
    Dim Ymax As Double = aChart.ChartAreas(0).AxisY.ScaleView.ViewMaximum

    Dim VisibleDataPoints As New Series

    For Each pt As System.Windows.Forms.DataVisualization.Charting.DataPoint In aChart.Series(0).Points
        If pt.XValue >= Xmin And pt.XValue <= Xmax Then
            If pt.YValues(0) >= Ymin And pt.YValues(0) <= Ymax Then
                VisibleDataPoints.Points.Add(pt)
            End If
        End If
    Next
    VisibleDataPoints.ChartType = System.Windows.Forms.DataVisualization.Charting.SeriesChartType.Line
    VisibleDataPoints.Color = Color.Red
    aChart.Series.Add(VisibleDataPoints)

HTH