c# - .net 如何删除最旧的数据 XY 点，然后将新的 XY 数据点添加到图表

Question

我正在使用 .Points.RemoveAt(0) 删除最旧的和 .AddXY 添加最新的。

但图表工作不正常。当我删除每个最旧的并添加每个最新的（x 轴是时间）时，我没有看到图表向左滚动，正如我所料。

标签： c#.netchartsseries

Answer 1

糟糕，我用 VBA 回答，而不是C#. 好吧，也许您可​​以C#通过读入值数组、修改它并将其写回图表来实现相同的技巧。

我认为你正在尝试做这样的事情：

这是我用来执行此操作的代码：

Private Const MaxPoints As Long = 100

Private Sub CommandButton1_Click()
    Dim i As Long, PI As Double
    PI = 4 * Atn(1)
    For i = 1 To 720 / 5
        AddValueToChart 50# + 35# * Sin(5 * i * PI / 180)
        DoEvents
    Next i
End Sub

Public Sub AddValueToChart(ByVal x As Double)
    Dim ch As Chart, list() As Variant
    Set ch = Me.ChartObjects("Chart 1").Chart

    Dim serlist As SeriesCollection
    Set serlist = ch.SeriesCollection()
    ' If chart is empty then add a line with 100 points
    If serlist.Count = 0 Then
        serlist.NewSeries
        ReDim list(1 To MaxPoints)
        ch.SeriesCollection(1).Values = list
    End If

    Dim ser As Series
    Set ser = ch.SeriesCollection(1)
    ' Get an array of values
    list = ser.Values
    Dim i As Long
    For i = MaxPoints To 2 Step -1
        ' Shift points
        list(i) = list(i - 1)
    Next i
    ' Add a new point to the begining of the chart.
    list(1) = x
    ' Assign the modified list as values of the series.
    ser.Values = list
End Sub