This topic explains how to enable/disable the selection of multiple diagram items in the xamDiagram™ control and how to perform selection programmatically.
The following topics are prerequisites to understanding this topic:
This topic contains the following sections:
The xamDiagram control provides functionality enabling the programmatic select of diagram items located on its space. There are several types of selection functionality available - single, multiple, and none, which all can be configured through a property setting. By default, multiple diagram items selection is enabled.
It is possible to select a diagram item either by clicking the left mouse button or drawing a selection rectangle holding the left mouse button down while moving the mouse across the diagram space until all desired diagram items fall within the boundaries of the dash-bordered selection rectangle and then releasing the mouse left button. (For more details see Diagram Items Interactions and Usability.)
Selecting diagram items in the context of the diagram control is useful in visually highlighting an item or a group of items (enclosing the item(s) within a dash-bordered rectangle) when rendering and/or configuring it. This could be achieved using either the options pane or via code. Configure the diagram items selection behavior by setting the xamDiagram control’s SelectionMode property to the specific type of selection desired. By default, multiple elements selection is the property default setting (SelectionMode="Multiple").
It is possible to programmatically change the selection state of a diagram item using the property setting ( DiagramItem.IsSelected), implemented separately from the user interaction selection functionality.
The selection of the diagram items populates the SelectedItems collection and fires the SelectionChanged event each time this collection changes, allowing for the application of custom logic to its members such as programmatically adding/removing diagram items, etc. When data binding is used, the SelectedDataItems collection is kept in sync with the SelectedItems and contains the data items corresponding to the selected diagram items.
The following table briefly explains the configurable aspects of diagram items selection and maps them to the properties that configure them.
To specify how many diagram items can be included in a selection on the diagram space, configure the control’s selection mode. The default setting enables multiple diagram items selection on the diagram, so to limit the number of items to one, set the value of the SelectionMode property to “Single” ; alternately set it to “None” to disable selection.
The following table summarizes the user interaction capabilities of the xamDiagram control with respect to the SelectionMode property setting.
The following table maps the desired configuration to the property settings that manage it.
The xamDiagram control allows you to select and de-select items programmatically. You select or de-select an item by configuring its selection state as determined by the value of the IsSelected property.
The following table maps the desired configuration to the property settings that manage it.
The screenshot below demonstrates node selection state configuration as a result of the following settings:
Following is the code that implements this example.
In XAML:
<ig:XamDiagram x:Name="diagram"
Width="300"
Height="250"
Background="#F9F9F9">
<ig:DiagramNode x:Name="node0"
Position="5,125"
IsSelected=”True”/>
</ig:XamDiagram>The following topics provide additional information related to this topic.