Question

In my vb.net project, I use zedgraph to draw figures. I find that the following properties work well to zoom figure on the center of mouse.

    Friend WithEvents gcMain As ZedGraph.ZedGraphControl
    Me.gcMain.IsZoomOnMouseCenter = True
    Me.gcMain.IsEnableWheelZoom = True

I have two toolstrip text boxes to show the minimum and maximum values of x axis. When I change values in text boxes, the x axis changes. The following code shows an example of handling the textbox. However I do not know how to update values in text boxes when the figure is zoomed by using IsEnableWheelZoom property. In zedgraph, ZedGraphControl_MouseWheel is a protected event.

 Friend WithEvents tbxRangeStart As System.Windows.Forms.ToolStripTextBox
     Private Sub tbxRangeStart_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles tbxRangeStart.KeyDown
    Try
        If e.KeyCode = Keys.Enter Then
            ' Change x Axis here
        End If
    Catch
    End Try
End Sub

Answer 1

Use the ZoomEvent:

chart.ZoomEvent += chart_ZoomEvent
...
private void chart_ZoomEvent(ZedGraphControl sender, ZoomState oldState, ZoomState newState)
{
    textBoxMax.Text = chart.GraphPane.XAxis.Scale.Max.ToString();
    textBoxMin.Text = chart.GraphPane.XAxis.Scale.Min.ToString();
}