vb.net圖表動態更新數組

Question

我有一個計算圖形的數組，並繪製圖形的另一個子。 有兩個線程用於計算（getArrayForGraph（）），另一個用於繪圖圖形。

現在我希望圖形沿邊陣列更新函數繪圖，因爲數組很長（10 000 000），使得整個過程非常緩慢。

我如何開始更新圖表，只要點可用於圖表。或者哪個是解決性能問題的最佳途徑。

Sub getArrayForGraph() 

    Dim time As Single = 0, finalTime As Single = 0 

    Dim timeinterval As Decimal 'function calulates values in picoseconds 
    Dim timeforGraph() As Long 
    ReDim timeforGraph(TotalSample - 1) 

    For index = 0 To TotalSample - 1 
     If index = 0 Then 
      finalTime = time 
     Else 
      finalTime += timeinterval 
     End If 
     timeforGraph(index) = Math.Round(finalTime, 3) 
    Next 
End Sub 

Sub plotGraph() 

    Chart1.Series("series1").Points.DataBindXY(timeforGraph, bufferDMv) 
     'bufferAMV is array calculated from another for loop 
end sub 

Answer 1

下面是一個完整的例子。它使用BackgroundWorker來執行工作，該工作向UI發送信號以進行更新。它也彙總數據。我選擇只顯示2000點，因爲1. MSChart不能處理很多點，2.我的顯示器只有1920像素寬，所以沒有必要嘗試顯示更多。此示例將爲每5k（10M/2k）點繪製1點，即x：最新時間，y：平均值。如果你願意的話，你也可以選擇平均時間，但這種情節會更加平庸。

它不包括您的具體變量，因爲有一些缺少的信息。但你應該明白它是如何工作的並使其在你的環境中工作

Public Class Form1 

    Private worker As System.ComponentModel.BackgroundWorker 

    Private chartX As New List(Of Long)() 
    Private chartY As New List(Of Long)() 

    ' settings for demo 
    Private count As Long = 10000000 
    Private numberOfGroups As Long = 2000 
    Private groupSize As Long = count/numberOfGroups 

    Private Sub doWork(sender As Object, e As System.ComponentModel.DoWorkEventArgs) 
     ' holds chunk of data to be grouped 
     Dim temp As New List(Of Tuple(Of Long, Long))() 
     For i As Long = 1 To count 
      ' generate some scientific data! 
      temp.Add(New Tuple(Of Long, Long)(i, Convert.ToInt64(i * Math.Sin(Math.PI * i/count) * Math.Sin(i)))) 
      ' make this happen 10 times 
      If i Mod count/10 = 0 Then 
       ' group the time and data into same groupings 
       Dim aggregate = 
        temp. 
        Select(Function(d, index) New Tuple(Of Integer, Tuple(Of Long, Long))(index, d)). 
        GroupBy(Function(d) Math.Floor(d.Item1/groupSize)) 
       ' take the latest time 
       Dim xAggregate = 
        aggregate. 
        Select(Function(a) a.Max(Function(b) b.Item2.Item1)). 
        ToArray() 
       ' take the average data 
       Dim yAggregate = 
        aggregate. 
        Select(Function(a) Convert.ToInt64(a.Average(Function(b) b.Item2.Item2))). 
        ToArray() 
       ' clear temp data 
       temp.Clear() 
       ' -- calling resetChartData() here would make the chart display only the currently processed data 
       ' -- might be useful if you were displaying data from an oscilloscope for instance 
       ' resetChartData() 
       ' add the aggregate data to the chart source data 
       chartX.AddRange(xAggregate) 
       chartY.AddRange(yAggregate) 
       ' report progress (initiate charting) 
       DirectCast(sender, System.ComponentModel.BackgroundWorker).ReportProgress(Convert.ToInt32(100 * i/count)) 
      End If 
     Next 
    End Sub 

    Private Sub progressChanged(sender As Object, e As System.ComponentModel.ProgressChangedEventArgs) 
     ' ui thread runs here. 
     ' perform minimal ui operations as not to slow down ui thread 
     ' added a progress bar, nice to see 
     ProgressBar1.Value = e.ProgressPercentage 
     ' databind the data 
     Chart1.Series("Series1").Points.DataBindXY(chartX, chartY) 
    End Sub 

    Private Sub resetChartData() 
     chartX.Clear() 
     chartY.Clear() 
    End Sub 

    Private Sub runWorkerCompleted(sender As Object, e As System.ComponentModel.RunWorkerCompletedEventArgs) 
     Button1.Enabled = True 
    End Sub 

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click 
     ' to prevent double clicks 
     Button1.Enabled = False 
     worker = New System.ComponentModel.BackgroundWorker() 
     AddHandler worker.DoWork, AddressOf doWork 
     AddHandler worker.ProgressChanged, AddressOf progressChanged 
     AddHandler worker.RunWorkerCompleted, AddressOf runWorkerCompleted 
     worker.WorkerReportsProgress = True 
     ' do work on background thread 
     worker.RunWorkerAsync() 
    End Sub 

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load 
     ' set up chart 
     Chart1.Series.Add("Series1") 
     Chart1.Series.Single().MarkerStyle = DataVisualization.Charting.MarkerStyle.None 
     Chart1.Series.Single().ChartType = DataVisualization.Charting.SeriesChartType.FastLine 
     Chart1.Legends.Clear() 
    End Sub 

End Class