Why does auto Zoom/Scroll not work for my Chart?

Question

to make it short I checked on the "WinFormsChartSamples" provided by Microsoft. What I wanted to know is how to enable zooming and scrolling for Chartcontrols. The example which is shown there is pretty short.

using System.Windows.Forms.DataVisualization.Charting;
...

// Set automatic zooming
chart1.ChartAreas["Default"].AxisX.ScaleView.Zoomable = true;
chart1.ChartAreas["Default"].AxisY.ScaleView.Zoomable = true;

// Set automatic scrolling 
chart1.ChartAreas["Default"].CursorX.AutoScroll = true;
chart1.ChartAreas["Default"].CursorY.AutoScroll = true;

...

I tried this and nothing happened, no zooming and no scrolling. I tried two things:

1. In Form1.Designer.cs I added that information to the chart.

       chartArea1.Name = "ChartArea1";
       chartArea1.CursorX.AutoScroll = true;
       chartArea1.CursorY.AutoScroll = true;
   
       chartArea1.AxisX.ScaleView.Zoomable = true;
       chartArea1.AxisY.ScaleView.Zoomable = true;
   
       this.chart1.ChartAreas.Add(chartArea1);
       this.chart1.Cursor = System.Windows.Forms.Cursors.Cross;
       legend1.Name = "Legend1";
       this.chart1.Legends.Add(legend1);
       this.chart1.Location = new System.Drawing.Point(297, 62);
       this.chart1.Name = "chart1";
       series1.ChartArea = "ChartArea1";
       series1.Legend = "Legend1";
       series1.Name = "Series1";
       this.chart1.Series.Add(series1);
       this.chart1.Size = new System.Drawing.Size(963, 668);
       this.chart1.TabIndex = 6;
       this.chart1.Text = "chart1";
   

2. I tried to add it directly into the constructor in Form1.cs.

Perhaps it is important to mention that I am using OpenFileDialog in order to add data to the series:

private void openToolStripMenuItem_Click(object sender, EventArgs e)
        {

            Stream fileStream = null;
            OpenFileDialog fDialog = new OpenFileDialog();
            fDialog.Title = "Open File..";
            //First the description of the file separated by "|"
            fDialog.Filter = "((ASC files)| *.asc";
            fDialog.InitialDirectory = @"C:\";

            //Show Messagebox if the file was loaded (Source: MSDN - FileDialog.FilterProperty)
            if (fDialog.ShowDialog() == DialogResult.OK)
            {
                MessageBox.Show("The File was loaded successfully.");

                try
                {
                    if ((fileStream = fDialog.OpenFile()) != null)
                    {
                        using (fileStream)
                        {
                            //Insert code for reading the stream here.
                            Spectrum newSpectrum = new Spectrum(chart1.Series.Count, fDialog.FileName,
                               fDialog.SafeFileName, DataHandler.readSpectrumFromFile(fileStream));

                            addSpectrumToView(newSpectrum);

                        }
                    }
                }
                catch (Exception ex)
                {
                    MessageBox.Show(ex.Message);
                }

            }
        }

Any advice is welcome, thanks in advance,

BC++

Solution 1

Have a look here: http://archive.msdn.microsoft.com/mschart There is an example there which does zooming/scrolling and much, much more! :)

Solution 2

I think you were actually really looking for this:

chart1.ChartAreas["Default"].CursorX.IsUserSelectionEnabled = true;
chart1.ChartAreas["Default"].CursorY.IsUserSelectionEnabled = true;

used in conjunction with what you already have should work well, which should look like this:

// Set automatic zooming
chart1.ChartAreas["Default"].AxisX.ScaleView.Zoomable = true;
chart1.ChartAreas["Default"].AxisY.ScaleView.Zoomable = true;

// Set automatic scrolling 
chart1.ChartAreas["Default"].CursorX.AutoScroll = true;
chart1.ChartAreas["Default"].CursorY.AutoScroll = true;

// Allow user selection for Zoom
chart1.ChartAreas["Default"].CursorX.IsUserSelectionEnabled = true;
chart1.ChartAreas["Default"].CursorY.IsUserSelectionEnabled = true;

Solution 3

To enable easy zooming, add a trackbar and use it to zoom:

    private void trackBar1_Scroll(object sender, EventArgs e)
    {
        chart1.ChartAreas[0].AxisX.ScaleView.Size = trackBar1.Maximum - trackBar1.Value;
        chart1.ChartAreas[1].AxisX.ScaleView.Size = trackBar1.Maximum - trackBar1.Value;
        (etc for however many chart areas you have)
    }

the "maximium - value" is to so that the higher the trackbar value, the fewer points are shown (closer zoom)

and make sure that in designer the 'chart1->ChartAreas->Axes->(whichever axes)->scaleview->zoomable' is set to true

A scroll bar will normally appear when a datapoint exceeds the scaleview size of an axis, if it has been set (scrolling doesn't really work reliably if left at 'auto'), if it hasn't, set it, if a scrollbar doesn't appear, a trackbar can yet again be used:

    private void trackBar2_ValueChanged(object sender, EventArgs e)
    {
        chart1.ChartAreas[0].AxisX.ScaleView.Position = trackBar2.Value;
        chart1.ChartAreas[1].AxisX.ScaleView.Position = trackBar2.Value;
        (etc for however many chart areas you have)
    }

Make sure you set the "Maximum" in the trackbars to a nice high number (eg 5000) and "Value" to what you desire it to load at.

Have yet to notice too much of a difference between "trackBar_Scroll" and "trackBar_ValueChanged", except "ValueChanged" works if the trackbar is moved by the program or user mouse click, whereas "Scoll" only works if moved by users mouse click.

Anything I missed?

Solution 4

My users dislikes the standard behavior of the mschart zooming and scrolling. That's why I implement a mouse based zoom/scroll that use dragging and mousewheel on axises.

The source code is here: https://bitbucket.org/controlbreak/mschartfriend

It is very simple and short, you can change it very quickly if you need.

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