Scrollpager doevents and margins of the main chart

[acastro]

Please find attached this example
http://193.145.251.126/pnp/files/uOpbmT ... Scroll.zip

If you press button10 and then button1, the margin of the main chart is not correct. But if you comment the "DoEvents" instruction it runs sucessfully. Why?

Thanks

[Christopher]

If you press button10 and then button1, the margin of the main chart is not correct. But if you comment the "DoEvents" instruction it runs sucessfully. Why?

I'm not sure, but according to this MSDN article:

Caution
Calling this method causes the current thread to be suspended while all waiting window messages are processed. If a message causes an event to be triggered, then other areas of your application code may execute. This can cause your application to exhibit unexpected behaviors that are difficult to debug. If you perform operations or computations that take a long time, it is often preferable to perform those operations on a new thread. For more information about asynchronous programming, see Asynchronous Programming Model (APM).

[acastro]

If you press button10 and then button1, the margin of the main chart is not correct. But if you comment the "DoEvents" instruction it runs sucessfully. Why?

I'm not sure, but according to this MSDN article:

Caution
Calling this method causes the current thread to be suspended while all waiting window messages are processed. If a message causes an event to be triggered, then other areas of your application code may execute. This can cause your application to exhibit unexpected behaviors that are difficult to debug. If you perform operations or computations that take a long time, it is often preferable to perform those operations on a new thread. For more information about asynchronous programming, see Asynchronous Programming Model (APM).

As you can see in the example application it doesn't do anything special with doevents.

It is only a example application to reproduce the problem I have in the real application, it is because the user adds the series, and after do other things it fills it with data. This is only a demonstration it is a error in the teechart.

In fact, you can export this chart with the problem in the margin, and if you open it again the problem is solved...

[Christopher]

It is only a example application to reproduce the problem I have in the real application, it is because the user adds the series, and after do other things it fills it with data. This is only a demonstration it is a error in the teechart.

No, it is not an error in TeeChart. The MSDN caution is quite clear. Calling Application.DoEvents() causes the current thread to be suspended, which for a Graphics application which depends on a running thread to do its calculations is bound to be problematic.

If you were to call Application.DoEvents() *after* TeeChart has finished all its calculations, that is, when it has finished drawing, then this is likely to be much less problematic. As an example, the following code works without any unexpected behaviour:

Code: Select all

        private void button10_Click(object sender, EventArgs e)
        {
          tChart1.AfterDraw += tChart1_AfterDraw;


          Steema.TeeChart.Styles.Line line = new Steema.TeeChart.Styles.Line(tChart1.Chart);
          line.LinePen.Width = 2;

          tChart1.Series.Add(line);

          tChart1.Series[0].XValues.DateTime = true;

          tChart1.Series[0].Add(new DateTime(2009, 7, 1, 0, 0, 0), 6525.4632);
          tChart1.Series[0].Add(new DateTime(2009, 7, 1, 0, 30, 0), 6325.000016);
        }

        void tChart1_AfterDraw(object sender, Steema.TeeChart.Drawing.Graphics3D g)
        {
          Application.DoEvents();
        }

[acastro]

Ok, forget doevents, it was only an example, it is not the main issue.

Please change my example, add a new button Button11 like this code. And press button10, then button11, and then button1... You have the same problem...

Code: Select all

  private void button10_Click(object sender, EventArgs e)
        {

            Steema.TeeChart.Styles.Line line = new Steema.TeeChart.Styles.Line(tChart1.Chart);
            line.LinePen.Width = 2;

            tChart1.Series.Add(line);

            tChart1.Series[0].XValues.DateTime = true;

        }

        private void button11_Click(object sender, EventArgs e)
        {
            tChart1.Series[0].Add(new DateTime(2009, 7, 1, 0, 0, 0), 6525.4632);
            tChart1.Series[0].Add(new DateTime(2009, 7, 1, 0, 30, 0), 6325.000016);
        }

[Christopher]

Please change my example, add a new button Button11 like this code. And press button10, then button11, and then button1... You have the same problem...

Okay, I can see the problem now. It has nothing to do with the scrollpager tool. I have added it to our bugtracker with id=590.

[acastro]

Ok. thanks

[Christopher]

Ok. thanks

FYI: this defect has now been fixed, and I've checked with your scrollpager code that all works as expected. Using Application.DoEvents also works as in your previous example of button10_Click

[acastro]

Nice thanks a lot!