IOSTutorial3

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Tutorial 3 - Chart Paging


If the data source for your Chart contains more data than can legibly be displayed on one Chart screen you may wish to divide the Chart into pages that can be leafed through. This can be achieved programmatically.

Paging by code

Paging properties and methods are available via the Page class.
Steps required to add paging to your Chart:

  • Define Points per page

Use MaxPointsPerPage to define the number of points to display on each page:

[C#.Net] 
tChart1.Page.MaxPointsPerPage = 10;


  • Add Navigation buttons to the Chart's Form.

Example: First Page

[C#.Net] 
tChart1.Page.Current = 0;

Advance a page

[C#.Net] 
tChart1.Page.Next();

Goto previous page

[C#.Net] 
tChart1.Page.Previous();

Last Page

[C#.Net] 
tChart1.Page.Current = tChart1.Page.Count;
  • Decide what to do with the last page.

The last page is unlikely to have exactly the correct number of points to match the point quantity in the other Chart pages. You may choose to Scale the Last page which will 'best fit' the remaining points to the page, adjusting the axis scale accordingly, or you may treat the page as previous pages with the same number of points which may leave the last page rather empty if there are not many points for the page.

[C#.Net] 
tChart1.Page.ScaleLastPage = false;   (default = true)
  • Show the user a page number

The PageNumber Chart Tool may be used to achieve this end:

[C#.Net] 
private void Initialize()
{
Bar bar1 = new Bar();
PageNumber pageNumber1 = new PageNumber();
tChart1.Series.Add(bar1);
tChart1.Tools.Add(pageNumber1);
bar1.FillSampleValues(100);
tChart1.Page.MaxPointsPerPage = 10;
}
{
this.button1.TouchUpInside += (sender, e) =>
{
tChart1.Page.Previous();
};
this.button2.TouchUpInside += (sender, e) =>
{
tChart1.Page.Next();
};

That's all for this tutorial ! The next tutorial deals with advanced Axis manipulation.



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