Accessing data properties

To access properties related to a graph’s data during
execution, you use DataWindow methods for graphs. There are three categories
of these methods related to data:

• Methods that provide information about a graph’s
  data
• Methods that save data from a graph
• Methods that change the color, fill patterns, and
  other visual properties of data

How to use the methods

To call the methods for a graph in a DataWindow control, use
the following syntax:

For example, there is a method CategoryCount, which returns
the number of categories in a graph. So to get the category count
in the graph gr_printer (which is in the DataWindow control
dw_sales), write:

Getting information about the data

There are quite a few methods for getting information about
data in a graph in a DataWindow control at execution time. For all
methods, you provide the name of the graph within the DataWindow
as the first argument. You can provide your own name for graph controls
when you insert them in the DataWindow painter. If the presentation
style is Graph, you do not need to name the graph.

PowerBuilder These methods get information about the data and its display. For
several of them, an argument is passed by reference to hold the
requested information:

Method	Information provided
CategoryCount	The number of categories in a graph
CategoryName	The name of a category, given its number
DataCount	The number of data points in a series
FindCategory	The number of a category, given its name
FindSeries	The number of a series, given its name
GetData	The value of a data point, given its series and position (superseded by GetDataValue, which is more flexible)
GetDataPieExplode	The percentage at which a pie slice is exploded
GetDataStyle	The color, fill pattern, or other visual property of a specified data point
GetDataValue	The value of a data point, given its series and position
GetSeriesStyle	The color, fill pattern, or other visual property of a specified series
ObjectAtPointer	The graph element the mouse was positioned over when it was clicked
SeriesCount	The number of series in a graph
SeriesName	The name of a series, given its number

Web ActiveX These methods get information about the data and its display. There
are additional helper methods available whenever the equivalent PowerBuilder
method uses an argument passed by reference. These helper methods
are identified in the second column of the following table (and
are described in the DataWindow Reference
):

Method	Information provided
CategoryCount	The number of categories in a graph
CategoryName	The name of a category, given its number
DataCount	The number of data points in a series
FindCategory	The number of a category, given its name
FindSeries	The number of a series, given its name
ObjectAtPointer	The graph element the mouse was positioned over when it was clickedCall ObjectAtPointerSeries and ObjectAtPointerDataPoint to get additional information
SeriesCount	The number of series in a graph
SeriesName	The name of a series, given its number
Getting information about a data point’s appearance
GetDataPieExplode	The percentage at which a pie slice is explodedCall GetDataPieExplodePercentage to retrieve the requested value
GetDataStyleColor	The color of a specified data pointCall GetDataStyleColorValue to retrieve the requested value
GetDataStyleFill	The fill pattern of a specified data pointCall GetDataStyleFillPattern to retrieve the requested value
GetDataStyleLine	The line style and width of a specified data pointCall GetDataStyleLineWidth and GetDataStyleLineStyle to retrieve the requested values
GetDataStyleSymbol	The symbol of a specified data pointCall GetDataStyleSymbolValue to retrieve the requested value
Getting a data point’s value
GetDataDate	The value of a data point that contains a date, given its series and positionCall GetDataDateVariable to retrieve the requested value
GetDataNumber	The value of a numeric data point, given its series and positionCall GetDataNumberVariable to retrieve the requested value
GetDataString	The value of a string data point, given its series and positionCall GetDataStringVariable to retrieve the requested value
Getting information about a series’ appearance
GetSeriesStyleColor	The color of a specified seriesCall GetSeriesStyleColorValue to retrieve the requested value
GetSeriesStyleFill	The fill pattern of a specified seriesCall GetSeriesStyleFillPattern to retrieve the requested value
GetSeriesStyleLine	The line style and width used by a specified seriesCall GetSeriesStyleLineWidth and GetSeriesStyleLineStyle to retrieve the requested values
GetSeriesStyleOverlay	Indication whether a series in a graph is an overlay (that is, whether it is shown as a line on top of another graph type)Call GetSeriesStyleOverlayValue to retrieve the requested value
GetSeriesStyleSymbol	The symbol of a specified seriesCall GetSeriesStyleSymbolValue to retrieve the requested value

Saving graph data

PowerBuilder The following methods allow you to save data from the graph:

Method	Action
Clipboard	Copies a bitmap image of the specified graph to the clipboard
SaveAs	Saves the data in the underlying graph to the clipboard or to a file in one of a number of formats

Web ActiveX You can save an image of the graph on the clipboard, but you cannot
save data in a file. Writing to the file system is a security violation
for an ActiveX control:

Method	Action
Clipboard	Copies a bitmap image of the specified graph to the clipboard

Modifying colors, fill patterns, and other data

PowerBuilder The following methods allow you to modify the appearance of data
in a graph:

Method	Action
ResetDataColors	Resets the color for a specific data point
SetDataStyle	Sets the color, fill pattern, or other visual property for a specific data point
SetSeriesStyle	Sets the color, fill pattern, or other visual property for a series

Web ActiveX These methods modify the appearance of data in a graph:

Method	Action
ResetDataColors	Resets the color for a specific data point
SetDataColor	Sets the color of a specified data point
SetDataFill	Sets the fill pattern of a specified data point
SetDataLine	Sets the line style and width of a specified data point
SetDataPieExplode	Explodes a slice in a pie graph
SetDataSymbol	Sets the symbol of a specified data point
SetSeriesColor	Sets the color of a specified series
SetSeriesFill	Sets the fill pattern of a specified series
SetSeriesLine	Sets the line style and width used by a specified series
SetSeriesOverlay	Specifies whether a series in a graph is an overlay (that is, whether it is shown as a line on top of another graph type)
SetSeriesSymbol	Sets the symbol of a specified series

Using graph methods

You call the data-access methods after a graph has been created
and populated with data. Some graphs, such as graphs that display
data for a page or group of data, are destroyed and re-created internally
as the user pages through the data. Any changes you made to the
display of a graph, such as changing the color of a series, are
lost when the graph is re-created.

Event for graph creation

To be assured that data-access methods are called whenever
a graph has been created and populated with data, you can call the
methods in the code for an event that is triggered when a graph
is created. The
event is:

• PowerBuilder Event ID pbm_dwngraphcreate, which you can assign
  to a user event for a DataWindow control (described below)
• Web ActiveX The onGraphCreate event

The graph-creation event is triggered by the DataWindow control
after it has created a graph and populated it with data, but before
it has displayed the graph. By accessing the data in the graph in
this event, you are assured that you are accessing the current data
and that the data displays the way you want it.

Setting up the PowerBuilder user event

PowerBuilder provides an event ID, pbm_dwngraphcreate,
that you can assign to a user event for a DataWindow control.

To access data properties of a graph in a DataWindow
control:

1. Place the DataWindow control in a window
   or user object and associate it with the DataWindow object containing
   the graph.

   Next you create a user event for the DataWindow control that
   is triggered whenever a graph in the control is created or changed.

2. Select the DataWindow control.

3. Select Declare>User Events from the menu
   bar.

   The Events dialog box displays all the events defined for
   the DataWindow control.

4. Name the user event you are creating. You might
   call it GraphCreate.

5. Assign it the event ID pbm_dwngraphcreate
   by double-clicking pbm_dwngraphcreate in the Paste Event
   ID box:

   

6. Click OK to save the new user event.

7. Write a script for the new GraphCreate event that
   accesses the data in the graph. Use the data-access methods listed
   above.

   Calling these methods in the GraphCreate event assures you
   that the data access happens each time the graph has been created
   or changed in the DataWindow.

Examples

PowerBuilder The following statement sets to black the foreground (fill) color
of the Q1 series in the graph gr_quarter, which is in the
DataWindow control dw_report. The statement is in the GraphCreate
event, which is associated with the event ID pbm_dwngraphcreate
in PowerBuilder:

The following statement changes the foreground (fill) color
to red of the second data point in the Stellar series in the graph
gr_sale in a window. The statement can be in a script for
any event:

Web ActiveX The following statement sets the foreground (fill) color to black
in one of the series in the graph gr_quarter, which is
in the DataWindow control dw_report. The statement is in
the onGraphCreate event:

For more information

For complete information about the data-access graph methods,
see the DataWindow Reference
.

For more about PowerBuilder user events, see the PowerBuilder
User’s Guide
.

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