Lock MSChart Gridlines

问题:

How do I do the following with an MSChart?

1. Set axes to x: [0 - 1000] and y: [0 - 1].
2. Show the gridlines when chart has no points.
3. Disable auto adjusting of gridlines.

Note: Setting Axis(X/Y).(Min/Max)imum seems to have no effect if a point exists inside the bounds.

回答1:

Question 1) is nicely answered by Bentley Davis, by setting the min and max values of the X and Y axes.

Question 3) requires one more property for each axis; the .Interval property. If you do not set the Interval, the MSChart will automatically do a best-fit interval between your declared min and max, thus potentially changing the positioning of the gridlines and the labels.

  Chart1.Legends.Clear()

  Chart1.Series("Series1").ChartType = SeriesChartType.FastLine
  With Chart1.ChartAreas(0)
     .AxisX.Maximum = 1000
     .AxisX.Minimum = 0
     .AxisY.Maximum = 1
     .AxisY.Minimum = 0
     .AxisX.Interval = 200
  End With
   End Sub

   Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
      Chart1.Series("Series1").Points.AddXY(100, 0.5)

   End Sub

   Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
      Chart1.Series("Series1").Points.AddXY(200, 0.6)

   End Sub

Question 2): You must add at least 1 data point to some series to display the gridlines. There is no way around this. I add the following series to my Charts when I want to duplicate that behavoir:

  Dim nSer As Series = Chart1.Series.Add("fake_Series")
  nSer.ChartType = SeriesChartType.Point
  nSer.MarkerSize = 0
  nSer.Points.Add(2000, 2)

The point does not display on the chart, but the gridlines are displayed.

回答2:

I am not able to recreate your problem. When I set the axes and the grid lines display then I add points the grid lines to not chnage. You seem to say that they do change. Here is the code I am using. I might be able to help if I can see example code.

    Chart1.Series("Series1").ChartType = SeriesChartType.FastLine
    Chart1.ChartAreas(0).AxisX.Maximum = 1000
    Chart1.ChartAreas(0).AxisX.Minimum = 0
    Chart1.ChartAreas(0).AxisY.Maximum = 1
    Chart1.ChartAreas(0).AxisY.Minimum = 0
    Chart1.Series("Series1").Points.AddXY(100, 0.5)
    Chart1.Series("Series1").Points.AddXY(200, 0.6)