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How to restrict Connector's source/target changing from native Nodes to other Nodes in WPF Diagram(SfDiagram)?
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WPF Diagram (SfDiagram) supports restricting connector’s source and target changing from native nodes to other nodes. You can achieve your requirement by using ConnectorSourceChangedCommand/ConnectorSourceChangedEvent and ConnectorTargetChangedCommand/ConnectorTargetChangedEvent. When you are trying to change the source and the target nodes of a connector from its native nodes to any other nodes, then source and target nodes will be reset to the same source and target nodes using event arguments.
XAML
<!--Initialize the Sfdiagram-->
<syncfusion:SfDiagram x:Name="diagram"
Nodes="{Binding Nodes}"
Connectors="{Binding Connectors}"
ConnectorSourceChangedCommand="{Binding ConnectorSourceChangedCommand}"
ConnectorTargetChangedCommand="{Binding ConnectorTargetChangedCommand}">
</syncfusion:SfDiagram>
C#
//Adding Commands
ConnectorSourceChangedCommand = new DelegateCommand(OnConnectorSourceChangedCommand);
ConnectorTargetChangedCommand = new DelegateCommand(OnConnectorTargetChangedCommand);
//Method to execute ConnectorSourceChangedCommand.
private void OnConnectorSourceChangedCommand(object parameter)
{
var args = parameter as ChangeEventArgs<object, ConnectorChangedEventArgs>;
if (args.NewValue.Node == null && args.OldValue.Node != null)
{
NodeViewModel node = args.OldValue.Node as NodeViewModel;
//Reset source node when it is changed to null from source node.
(args.Item as ConnectorViewModel).SourceNode = node;
}
}
//Method to execute ConnectorTargetChangedCommand.
private void OnConnectorTargetChangedCommand(object parameter)
{
var args = parameter as ChangeEventArgs<object, ConnectorChangedEventArgs>;
if (args.NewValue.Node == null && args.OldValue.Node != null)
{
NodeViewModel node = args.OldValue.Node as NodeViewModel;
//Reset target node when it is changed to null from target node.
(args.Item as ConnectorViewModel).TargetNode = node;
}
}
