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Accessing data properties

Getting information about the data
Saving graph data
Modifying colors, fill patterns, and other data
Using graph methods

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: 

DataWindowName.methodName ( "graphName", otherArguments... )

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: 

Ccount = dw_sales.CategoryCount("gr_printer")

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The value of a data point, given its series and position (superseded by GetDataValue, which is more flexible)

GetDataLabelling

The display setting for the data label at a given data point in a DirectX 3D graph

GetDataPieExplode

The percentage at which a pie slice is exploded

GetDataStyle

The color, fill pattern, or other visual property of a specified data point

GetDataTransparency

The transparency percentage of a data point in a DirectX 3D graph

GetDataValue

The value of a data point, given its series and position

GetSeriesLabelling

The display setting for the series label for a given series in a DirectX 3D graph

GetSeriesStyle

The color, fill pattern, or other visual property of a specified series

GetSeriesTransparency

The transparency percentage of a series in a DirectX 3D graph

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


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


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

SetDataLabelling

Specifies the display setting for a data label in a DirectX 3D graph

SetDataStyle

Sets the color, fill pattern, or other visual property for a specific data point

SetDataTransparency

Sets the transparency percentage for a data point in a DirectX 3D graph

SetSeriesLabelling

Specifies the display setting for a series label in a DirectX 3D graph

SetSeriesStyle

Sets the color, fill pattern, or other visual property for a series

SetSeriesTransparency

Sets the transparency percentage of a series in a DirectX 3D graph


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)

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 Insert>Event from the menu bar.

    The Script view displays and includes prototype fields for adding a new event.

  3. Select the DataWindow control in the first drop-down list of the prototype window.

    If the second drop-down list also changes to display an existing DataWindow event prototype, scroll to the top of the list to select New Event or select Insert>Event once again from the menu bar.

    The sample screen shows the Script view with prototype fields for adding a new event. The DataWindow control dw_1 is selected in the first drop-down list at upper left. The second drop-down list, at upper right, displays (new Event). Additional drop down lists are access, which is grayed out, return type, with a default of none, Event Name, Pass By, with a default of value, and Argument Type, with a default of integer. Text input fields follow for Argument Name and throws:. There is a check box for External, and a drop down list for Event ID, with a default of none. At the bottom is an empty text display area for script.

  4. Name the user event you are creating.

    For example, you might call it GraphCreate.

  5. Select pbm_dwngraphcreate for the event ID.

    The sample window is titled Script - dw_1 for graph create returns long. The first drop down list displays dw_1. The second displays graph create ( ) returns long (pbm. The Event Name displayed is Graph Create, and the Event ID is pbm_dwngraphcreate.

  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.

    Calling data access 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: 

dw_report.SetSeriesStyle("gr_quarter", "Q1", &
       foreground!, 0)

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: 

int SeriesNum
 // Get the number of the series.
 SeriesNum = gr_sale.FindSeries("Stellar")

 // Change color of second data point to red
 gr_sale.SetDataStyle(SeriesNum, 2, foreground!, 255)

For more information

For complete information about the data-access graph methods, see Methods for Graphs in the DataWindow Control in DataWindow Reference.

For more about PowerBuilder user events, see Working with User Events in Users Guide.

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