Underlying and Displayed Data
- 4 minutes to read
All DevExpress Dashboard controls aggregate and visualize data from the underlying data source. This means that each dashboard item displays grouped and summarized data that differs from the data you supply to the control. This topic describes how you can access both displayed and underlying data.
The Dashboard control summarizes underlying data for each dashboard item and stores the data as an inner pivot table (hierarchical data representation).
Any dashboard item, regardless of the item type, stores its data as a multidimensional object that resembles a pivot table. This data storage method allows the control to have a consistent and compact API, but simple item-specific actions require complex API expressions.
Consider the Pivot item shown in the picture below.
The selected cell displays the measure value of the multidimensional data. To get this value, you need to slice the dashboard item data object against the axis points on the Row and Column data axes.
Dimension values for the selected cell are stored in two axis points - one for the Row axis, another for the Column axis. Different dashboard items have different axis names. A pivot has the Row and “ axes, a chart has the Argument and Series axes, other items have another axis. Dimension values comprise axis points as a hierarchical tree structure. An axis point is a tree node and has a parent and child nodes. The Column axis point related to the selected cell in the picture has one parent axis point (its display text is “1997”) and no child axis points. The Row axis point in the picture has one parent axis point (its display text is “Beverages”) and no child axis points.
The image below illustrates how the multidimensional data stores hierarchical data:
You can also get the slice of the current multidimensional data by the specified axis point. In the picture above, the slice by the “Product 3” axis point is highlighted in green. It contains measure values for all date intervals. The slice by the “May” axis point is highlighted in blue, it contains measure values for all products. If you get two sequential slices, you obtain the slice at the intersection of the “Product 3” and “May” axis points.
The slice of the multidimensional data is the axis point tuple that contains a set of axis points. The axis point tuple is used in API methods that operate with master filters or drill-down values.
Measure values are summaries calculated for measure data contained in the multidimensional data. You can obtain total summary values or summary values at the intersection of multiple axis points. For measure, you can get its value and display text.
Delta values are calculated for the following dashboard items:
When you get a delta, you can get its actual/target values, various delta settings and other multiple options.
You can also obtain summary values for hidden measures.
The dashboard visualizes aggregated data from the underlying data source. You can obtain underlying data for a particular dashboard item or a data set related to the specified axis point. The image below shows underlying data for the selected Chart bar.
We also recommend that you look at the Data Inspector. This dialog window allows you to obtain raw or aggregated data in the UI.
The DevExpress Dashboard controls have events that allow you to obtain client and underlying data related to the clicked visual element. You can use this data to implement custom interactivity between dashboard items.
Refer to the following platform articles for detailed API descriptions: