【TeeChart Pro ActiveX教程】（四）：轴控制—附加轴和轴事件

TeeChart提供5个轴与数据系列，Left，Right，Top，Bottom和Depth相关联。

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（一）附加轴

1.1 复制轴

TeeChart提供5个轴与数据系列，Left，Right，Top，Bottom和Depth相关联。向图表添加新系列时，可以定义系列应与哪些轴相关（转到“Series”选项卡“General”页面）。您可以使用Axis Customdraw方法在图表上的任何位置重复前4轴中的任何一个（或全部）。请注意，此方法会复制Axis，但不会添加新的自定义轴。

例：

'fill the Series for this example with random dataPrivate Sub Command1_Click()Dim t As Integer  For t = 0 To 20    TChart1.Series(0).AddXY t, ((100 * Rnd) + 1) - ((Rnd * 70) + 1), "", vbRed  Next tEnd Sub'Put this code in the TChart1_OnBeforeDrawSeries() event:Dim posaxis As Integer  With TChart1   If .Axis.Left.Maximum > 0 Then    'When scrolling or on zoom always keep the gridlines enclosed in the Chart rectangle    .Canvas.ClipRectangle .Canvas.Left, .Canvas.Top, (.Canvas.Left + .Canvas.Width), _                          (.Canvas.Top + .Canvas.Height)    'Always draw the 2nd vertical Axis at the middle point of the Chart    posaxis = (.Canvas.Left) + (.Canvas.Width * 0.5)    .Axis.Left.CustomDraw posaxis - 10, posaxis - 20, posaxis, True    'Draw the 2nd Horizontal axis at the level of "10" on the vertical axis    posaxis = (.Axis.Left.CalcYPosValue(10))    .Axis.Bottom.CustomDraw posaxis + 10, posaxis + 40, posaxis, True    .Canvas.UnClipRectangle   End If  End With

自定义轴

在此示例中，TeeChart将绘制新轴，一个水平，一个垂直位于图表的中心。当您滚动图表（用鼠标右键拖动）时，新的垂直轴将始终保持在图表的中心，新的水平轴将垂直滚动上下移动。新轴是默认轴的精确副本。

1.2 多个自定义轴

通过代码，例：

Private Sub Command1_Click()TChart1.Series(0).VerticalAxisCustom = TChart1.Axis.AddCustom(False)'You can modify any property of the new created axes, such as the axis color or axis titleWith TChart1.Axis.Custom(0)    .AxisPen.Color = vbGreen    .Title.Caption = "Extra axis"    .Title.Font.Bold = True    .Title.Angle = 90    .PositionPercent = 50 'percentage of Chart rectangleEnd WithEnd Sub

然后，您可以使用StartPosition和EndPosition属性将新轴与图表的整体关系定位。

StartPosition=50EndPosition=100

这些数字表示为图表矩形的百分比，其中0（零）（在垂直轴的情况下）为Top。这些属性可以应用于标准轴，以在图表中创建完全分区的“SubCharts”，例：

With TChart1.Axis.Left    .StartPosition = 0    .EndPosition = 50    .Title.Caption = "1st Left Axis"    .Title.Font.Bold = TrueEnd With

以上2个编码示例与以下数据结合使用：

For t = 0 To 10    TChart1.Series(0).AddXY t, 10 + t, "", clTeeColor    If t > 1 Then      TChart1.Series(1).AddXY t, t / 2, "", clTeeColor    End IfNext t

将显示以下图表：

多轴

（二）轴事件

Axis事件提供运行时灵活性，可以修改Axis标签并在Axis Clicks上显示用户交互性。

OnClickAxis

例：

Private Sub TChart1_OnClickAxis(ByVal Axis As Long, ByVal Button As TeeChart.EMouseButton, ByVal Shift As TeeChart.EShiftState, ByVal X As Long, ByVal Y As Long)'Shows Axis point clicked when click on Bottom Axis.If Axis = atBottom Then  MsgBox "Clicked Bottom Axis at " & TChart1.Axis.Bottom.CalcPosPoint(X)End IfEnd Sub

OnGetAxisLabel

可用于修改Axis标签，例：

Private Sub TChart1_OnGetAxisLabel(ByVal aAxis As Long, ByVal SeriesIndex As Long, ByVal ValueIndex As Long, LabelText As String)'Add following text to Bottom Axis LabelsIf aAxis = atBottom Then  LabelText = "Period " + LabelTextEnd IfEnd Sub

OnGetNextAxisLabel

可用于决定应显示哪些轴标签，使用MoreLabels Boolean属性来包含/排除轴标签，例：

Private Sub TChart1_OnGetNextAxisLabel(ByVal Axis As Long, ByVal LabelIndex As Long, LabelValue As Double, MoreLabels As Boolean)If Axis = atBottom Then   MoreLabels = True   'Only label if following cases are true   Select Case LabelIndex      Case 0: LabelValue = 11      Case 1: LabelValue = 19      Case 2: LabelValue = 23      Case Else: MoreLabels = False   End SelectEnd IfEnd Sub

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标签：图表ActiveXteechart