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

[vb]
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 www.2cto.com  
    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 


摘自 wl58796351的专栏