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  How to change XYChart Y Axis Minimum Value and Maximum Value
Posted by Raghu on Jan-03-2014 11:22
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Hello Peter,

I want to make the Y Axis Scale configurable by user. How can I change Y Axis Minimum Value and Maximum Value?

Take "multiaxes.vb" for example, I add a MouseClick function to change YAxis scale by "setLinearScale". But there is no any change on YAxis Scale. Could you help? Thanks.

Private Sub WinChartViewer1_Click(ByVal sender As System.Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles WinChartViewer1.Click
        Dim viewer As WinChartViewer = sender
        Dim c As XYChart = viewer.Chart
        Dim layer As LineLayer
        Dim result As DialogResult
        Dim fAixs As DialogAxis = New DialogAxis()

        If c.yAxis.getX - 75 < e.X And c.yAxis.getX - 45 > e.X Then
            MessageBox.Show("Left Axis!")
        End If

        If c.yAxis.getX - 35 < e.X And c.yAxis.getX > e.X Then
            fAixs.tbPyMin.Text = c.yAxis.getMinValue
            fAixs.tbPyMax.Text = c.yAxis.getMaxValue
            result = fAixs.ShowDialog()
            If result = Windows.Forms.DialogResult.OK Then
                c.yAxis().setLinearScale(fAixs.PyMin, fAixs.PyMax)
                viewer.updateDisplay()
            End If
        End If

        If c.yAxis2.getX < e.X And c.yAxis2.getX + 30 > e.X Then
            MessageBox.Show("Axis 2!")
        End If

        If c.yAxis2.getX + 40 < e.X And c.yAxis2.getX + 75 > e.X Then
            MessageBox.Show("Right Axis!")
        End If

    End Sub

  Re: How to change XYChart Y Axis Minimum Value and Maximum Value
Posted by Peter Kwan on Jan-04-2014 03:43
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Hi Raghu,

To change the chart, you need to redraw it. Assuming the subroutine that draws you chart is called "drawChart", the code should be like:

Dim useManualScale As Boolean
Private Sub WinChartViewer1_Click(ByVal sender As System.Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles WinChartViewer1.Click
        Dim viewer As WinChartViewer = sender
        Dim c As XYChart = viewer.Chart

        If c.yAxis.getX - 35 < e.X And c.yAxis.getX > e.X Then
            useManualScale = True
            drawChart()
        End If
End Sub


In your drawChart subdrouinte, the code should be like:

Sub drawChart()

     Dim c As XYChart = New XYChart(....)
     .... create chart as usual ....

     If useManualScale Then
         c.yAxis().setLinearScale(fAixs.PyMin, fAixs.PyMax)
         useManualScale = False
     End If

     WinChartViewer1.Chart = Chart

End Sub


Hope this can help.

Regards
Peter Kwan