vb.net chart图表使用技巧之一

很多朋友再为使用什么样曲线来显示数据发愁，当然有MONEY的朋友除外。其实微软已经给我们提供一个很强大免费的控件，那就是chart,当然这个控件只能再vs.2008以上的版本才能使用。不过很少有人介绍怎么使用。于是本人花了一天时间，认真进行学习。

详细的程序如下，中间我已经作了很多说明，呵呵

    Private AddDataRunner As Thread
    Private Rand As New Random()
    Public Delegate Sub AddDataDelegate()  '定义一个线程委托
    Public AddDataDel As AddDataDelegate
    Private minValue,maxValue As DateTime

    Private Sub Form2_Load(sender As System.Object,e As System.EventArgs) Handles MyBase.Load
        '定义一个新的线程进行循环执行
        Dim addDataThreadStart As New ThreadStart(AddressOf AddDataThreadLoop)
        '把线程交给公共线程来管理
        AddDataRunner = New Thread(addDataThreadStart)
        '委托交付管理
        addDataDel = New AddDataDelegate(AddressOf AddData)

    End Sub
   
    ''' <summary>
    ''' 主线程每秒循环一次，并通过委托,将数据发给你 CHART
    ''' </summary>
    ''' <remarks></remarks>
    Private Sub AddDataThreadLoop()
        While True
            chart1.Invoke(addDataDel)

            Thread.Sleep(1000)
        End While
    End Sub 'AddDataThreadLoop

    Public Sub AddData()
        Dim timeStamp As DateTime = DateTime.Now

        Dim ptA As ChartArea
        For Each ptA In Chart1.ChartAreas
            Dim ptSeries As Series
            '对每series进行数据扫描
            For Each ptSeries In Chart1.Series
                Dim k As Single
                k = Rand.Next(10,50)
                AddNewPoint(timeStamp,k,ptSeries)
            Next ptSeries
        Next
    End Sub 'AddData

  
    ''' <summary>
    ''' x轴为时间，y轴为数据,并根据随机数据进行填写；
    ''' </summary>
    ''' <param name="timeStamp"></param>
    ''' <param name="ptSeries"></param>
    ''' <remarks></remarks>
    Public Sub AddNewPoint(timeStamp As DateTime,ByVal pValue As Single,ptSeries As System.Windows.Forms.DataVisualization.Charting.Series)
        Dim newVal As Double = 0

        If ptSeries.Points.Count > 0 Then
            newVal = ptSeries.Points((ptSeries.Points.Count - 1)).YValues(0) + (Rand.NextDouble() * 2 - 1)
        End If

        If newVal < 0 Then
            newVal = 0
        End If

        ' Add new data point to its series.
        ptSeries.Points.AddXY(timeStamp.ToOADate,pValue)

        ' remove all points from the source series older than 1.5 minutes.
        Dim removeBefore As Double = timeStamp.AddSeconds((CDbl(90) * -1)).ToOADate()
        'remove oldest values to maintain a constant number of data points
        While ptSeries.Points(0).XValue < removeBefore
            ptSeries.Points.RemoveAt(0)
        End While

        Dim ptA As ChartArea
        For Each ptA In Chart1.ChartAreas
            ptA.AxisX.Minimum = ptSeries.Points(0).XValue
            ptA.AxisX.Maximum = DateTime.FromOADate(ptSeries.Points(0).XValue).AddMinutes(2).ToOADate()
        Next
      
        Chart1.Invalidate()
    End Sub

    ' Clean up any resources being used.
    Protected Overloads Overrides Sub dispose(ByVal disposing As Boolean)
        If (addDataRunner.ThreadState And ThreadState.Suspended) = ThreadState.Suspended Then
            addDataRunner.Resume()
        End If
        addDataRunner.Abort()

        If disposing Then
            If Not (components Is nothing) Then
                components.dispose()
            End If
        End If
        MyBase.dispose(disposing)
    End Sub 'dispose

  

    Private Sub startTrending_Click(sender As System.Object,e As System.EventArgs) Handles startTrending.Click
        ' 开始按钮状态
        startTrending.Enabled = False
        ' 停止按钮状态
        stopTrending.Enabled = True

        ' Predefine the viewing area of the chart
        minValue = DateTime.Now
        '2分钟预览区域
        maxValue = minValue.AddSeconds(120)

        Chart1.ChartAreas(0).AxisX.Minimum = minValue.ToOADate()
        Chart1.ChartAreas(0).AxisX.Maximum = maxValue.ToOADate()

        Chart1.ChartAreas(1).AxisX.Minimum = minValue.ToOADate()
        Chart1.ChartAreas(1).AxisX.Maximum = maxValue.ToOADate()

        ' Reset number of series in the chart.
        Chart1.Series.Clear()

        ' create a line chart series
        Dim newSeries1 As New Series("Series1")
        With newSeries1
            .LegendText = "曲线一"
            .ChartType = SeriesChartType.Line
            .BorderWidth = 1
            .Color = Color.Red
            .XValueType = ChartValueType.Time
        End With
        newSeries1.ChartArea = "ChartArea1"

        Dim newSeries2 As New Series("Series2")
        With newSeries2
            .LegendText = "曲线二"
            .ChartType = SeriesChartType.Line
            .BorderWidth = 1
            .Color = Color.Blue
            .XValueType = ChartValueType.Time
        End With
        newSeries2.ChartArea = "ChartArea2"

        Chart1.Series.Add(newSeries1)
        Chart1.Series.Add(newSeries2)

        ' start worker threads.
        If addDataRunner.IsAlive = True Then
            addDataRunner.Resume()
        Else
            addDataRunner.Start()
        End If
    End Sub

    Private Sub stopTrending_Click_1(sender As System.Object,e As System.EventArgs) Handles stopTrending.Click
        If addDataRunner.IsAlive = True Then
            addDataRunner.Resume()
        End If

        ' Enable all controls on the form
        startTrending.Enabled = True
        ' and only disable the Stop button
        stopTrending.Enabled = False
    End Sub