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Class SelectionController - Blazor API Reference | Syncfusion

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    Class SelectionController

    Represents a controller that provides object selection functionality within the SfDiagramComponent.

    Inheritance
    System.Object
    CommonController
    InteractionControllerBase
    SelectionController
    Inherited Members
    InteractionControllerBase.CurrentPosition
    InteractionControllerBase.InAction
    InteractionControllerBase.PreviousPosition
    InteractionControllerBase.StartPosition
    Namespace: Syncfusion.Blazor.Diagram
    Assembly: Syncfusion.Blazor.dll
    Syntax
    public class SelectionController : InteractionControllerBase
    Remarks

    The SelectionController manages the selection state of diagram objects and handles user interactions for selecting single or multiple objects through mouse clicks, keyboard shortcuts, and programmatic selection.

    Constructors

    SelectionController(SfDiagramComponent)

    Initializes a new instance of the SelectionController class with the specified diagram component.

    Declaration
    public SelectionController(SfDiagramComponent diagram)
    Parameters
    Type Name Description
    SfDiagramComponent diagram

    The SfDiagramComponent instance that this controller will manage selection operations for.

    Remarks

    The SelectionController manages selection state of diagram objects and handles user interactions for selecting nodes, connectors, and other visual elements.

    Methods

    OnMouseDown(DiagramMouseEventArgs)

    Handles the mouse down event when the user clicks on a diagram element to initiate selection operations.

    Declaration
    public override void OnMouseDown(DiagramMouseEventArgs args)
    Parameters
    Type Name Description
    DiagramMouseEventArgs args

    A DiagramMouseEventArgs containing mouse event information including position and target element.

    Overrides
    InteractionControllerBase.OnMouseDown(DiagramMouseEventArgs)
    Remarks

    Sets the InAction property to true and delegates to the base class for additional processing.

    OnMouseLeave(DiagramMouseEventArgs)

    Handles the mouse leave event when the mouse pointer exits a selected diagram element in the SelectionController.

    Declaration
    public override void OnMouseLeave(DiagramMouseEventArgs args)
    Parameters
    Type Name Description
    DiagramMouseEventArgs args

    A DiagramMouseEventArgs containing mouse event information including position and target element.

    Overrides
    InteractionControllerBase.OnMouseLeave(DiagramMouseEventArgs)
    Remarks

    Automatically triggered when the mouse leaves a selected diagram element.

    If InAction property is true, delegates to OnMouseUp(DiagramMouseEventArgs) to complete the ongoing selection operation.

    OnMouseMove(DiagramMouseEventArgs)

    Handles mouse move events during selection operations when the user clicks and drags selected elements in the diagram.

    Declaration
    public override bool OnMouseMove(DiagramMouseEventArgs args)
    Parameters
    Type Name Description
    DiagramMouseEventArgs args

    A DiagramMouseEventArgs containing mouse event information including position, target element, and button state.

    Returns
    Type Description
    System.Boolean

    A System.Boolean indicating whether the event was handled. Returns true when processing drag operations, false otherwise.

    Overrides
    InteractionControllerBase.OnMouseMove(DiagramMouseEventArgs)
    Remarks

    Invoked during selection operations when dragging elements. Handles position updates and visual feedback during drag operations.

    OnMouseUp(DiagramMouseEventArgs)

    Handles mouse up events when the user releases the mouse button after clicking on selected elements in the SfDiagramComponent.

    Declaration
    public override void OnMouseUp(DiagramMouseEventArgs args)
    Parameters
    Type Name Description
    DiagramMouseEventArgs args

    A DiagramMouseEventArgs containing mouse event information. Can be null.

    Overrides
    InteractionControllerBase.OnMouseUp(DiagramMouseEventArgs)
    Remarks

    Called when the mouse button is released on selected diagram elements to complete selection or drag operations.

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