除了可以定制轴标签的整体外观以外，还可以在运行时刻获得各个轴标签。然后，可以分别为它们应用所有可用的轴标签选项。例如，可以根据某些标准 (例如轴的临界值)，为轴标签应用不同的格式。

为此，推出了特殊的 ChartControl.CustomDrawAxisLabel 事件。接管此事件来获得轴标签。

注意
对于 WebChartControl，应该接管 WebChartControl.CustomDrawSeries 事件来完成此任务。

下列代码演示了这种功能的一种可行的实现方法。

C#	复制代码
private void chartControl1_CustomDrawAxisLabel(object sender, CustomDrawAxisLabelEventArgs e) { AxisBase axis = e.Item.Axis; if (axis is AxisY \|\| axis is AxisY3D \|\| axis is RadarAxisY) { double axisValue = (double)e.Item.AxisValue; if (axisValue < 0) { e.Item.TextColor = Color.Red; } else if (axisValue > 0) { e.Item.Text = "+" + e.Item.Text; e.Item.TextColor = Color.Green; } else if (axisValue == 0) { e.Item.Text = "Zero"; } } }

复制代码

private void chartControl1_CustomDrawAxisLabel(object sender, CustomDrawAxisLabelEventArgs e) {
    AxisBase axis = e.Item.Axis;
    if (axis is AxisY || axis is AxisY3D || axis is RadarAxisY) {
        double axisValue = (double)e.Item.AxisValue;
        if (axisValue < 0) {
            e.Item.TextColor = Color.Red;
        }
        else if (axisValue > 0) {
            e.Item.Text = "+" + e.Item.Text;
            e.Item.TextColor = Color.Green;
        }
        else if (axisValue == 0) {
            e.Item.Text = "Zero";
        }
    }
}

Visual Basic	复制代码
Private Sub chartControl1_CustomDrawAxisLabel(sender As Object, e As CustomDrawAxisLabelEventArgs) Dim axis As AxisBase = e.Item.Axis If TypeOf axis Is AxisY Or TypeOf axis Is AxisY3D Or TypeOf axis Is RadarAxisY Then Dim axisValue As Double = CDbl(e.Item.AxisValue) If axisValue < 0 Then e.Item.TextColor = Color.Red Else If axisValue > 0 Then e.Item.Text = "+" + e.Item.Text e.Item.TextColor = Color.Green Else If axisValue = 0 Then e.Item.Text = "Zero" End If End If End If End If End Sub

Visual Basic

复制代码

Private Sub chartControl1_CustomDrawAxisLabel(sender As Object, e As CustomDrawAxisLabelEventArgs)
   Dim axis As AxisBase = e.Item.Axis
   If TypeOf axis Is AxisY Or TypeOf axis Is AxisY3D Or TypeOf axis Is RadarAxisY Then
      Dim axisValue As Double = CDbl(e.Item.AxisValue)
      If axisValue < 0 Then
         e.Item.TextColor = Color.Red
      Else
         If axisValue > 0 Then
            e.Item.Text = "+" + e.Item.Text
            e.Item.TextColor = Color.Green
         Else
            If axisValue = 0 Then
               e.Item.Text = "Zero"
            End If
         End If
      End If
   End If
End Sub

在下面的插图中显示了结果。

Show Me
在 DevExpress Code Central 数据库中可以找到完整的示例项目，网址是 http://www.devexpress.com/example=E1469。取决于目标平台类型 (ASP.NET、WinForms 等)，可以在线运行本示例，或者下载自动可执行的示例。

参阅