Class BaseListViewElement

Represents an abstract base class for RadListView view elements providing core functionality for item virtualization, scrolling, selection management, keyboard navigation, and drag-drop operations. Extends VirtualizedScrollPanel<Item, Element> to provide specialized list view behavior with support for grouping, lasso selection, and various display modes.

Inheritance
System.Object
DisposableObject
RadObject
RadElement
VisualElement
RadComponentElement
RadItem
UIItemBase
LightVisualElement
ScrollViewElement<VirtualizedStackContainer<ListViewDataItem>>
VirtualizedScrollPanel<ListViewDataItem, BaseListViewVisualItem>
BaseListViewElement
DetailListViewElement
IconListViewElement
SimpleListViewElement
Inherited Members
System.Object.Equals(System.Object)
System.Object.Equals(System.Object, System.Object)
System.Object.ReferenceEquals(System.Object, System.Object)
System.Object.GetHashCode()
System.Object.GetType()
System.Object.MemberwiseClone()
Namespace: Telerik.WinControls.UI
Assembly: Telerik.WinControls.UI.dll

Syntax

public abstract class BaseListViewElement : VirtualizedScrollPanel<ListViewDataItem, BaseListViewVisualItem>, INotifyPropertyChanged, ICustomTypeDescriptor, ISupportSystemSkin, IComponent, IDisposable, IBindableComponent, ISupportDrag, ISupportDrop, IShortcutProvider, IStylableElement, IStylableNode, IPrimitiveElement, IShapedElement, IFillElement, IBorderElement, IBoxStyle, IBoxElement, IDrawFillElement, IImageElement, ITextPrimitive, ITextProvider

Constructors

BaseListViewElement(RadListViewElement)

Initializes a new instance of the BaseListViewElement class with the specified owner. Configures scrolling behavior, timers for editing and selection, drag-drop support, and keyboard navigation functionality.

Declaration
public BaseListViewElement(RadListViewElement owner)
Parameters
RadListViewElement owner

The RadListViewElement that owns this base list view element.

Fields

AllowArbitraryItemHeightProperty

Declaration
public static RadProperty AllowArbitraryItemHeightProperty
Field Value
RadProperty

AllowArbitraryItemWidthProperty

Declaration
public static RadProperty AllowArbitraryItemWidthProperty
Field Value
RadProperty

anchor

Declaration
protected ListViewDataItem anchor
Field Value
ListViewDataItem

beginEditTimer

Declaration
protected Timer beginEditTimer
Field Value
System.Windows.Forms.Timer

disableEditOnMouseUp

Declaration
protected bool disableEditOnMouseUp
Field Value
System.Boolean

disableGroupSelectOnMouseUp

Declaration
protected bool disableGroupSelectOnMouseUp
Field Value
System.Boolean

DragHintProperty

Declaration
public static RadProperty DragHintProperty
Field Value
RadProperty

endPoint

Declaration
protected Point endPoint
Field Value
System.Drawing.Point

FullRowSelectProperty

Declaration
public static RadProperty FullRowSelectProperty
Field Value
RadProperty

GroupIndentProperty

Declaration
public static RadProperty GroupIndentProperty
Field Value
RadProperty

GroupItemSizeProperty

Declaration
public static RadProperty GroupItemSizeProperty
Field Value
RadProperty

groupSelectionTimer

Declaration
protected Timer groupSelectionTimer
Field Value
System.Windows.Forms.Timer

isLassoSelection

Declaration
protected bool isLassoSelection
Field Value
System.Boolean

ItemSizeProperty

Declaration
public static RadProperty ItemSizeProperty
Field Value
RadProperty

lassoInitialSelection

Declaration
protected Dictionary<ListViewDataItem, bool> lassoInitialSelection
Field Value
System.Collections.Generic.Dictionary<ListViewDataItem, System.Boolean>

lastClickedItem

Declaration
protected ListViewDataItem lastClickedItem
Field Value
ListViewDataItem

lastModifierKeys

Declaration
protected Keys lastModifierKeys
Field Value
System.Windows.Forms.Keys

pointerOffset

Declaration
protected Point pointerOffset
Field Value
System.Drawing.Point

pressedItem

Declaration
protected BaseListViewVisualItem pressedItem
Field Value
BaseListViewVisualItem

SelectionRectangleBorderColorProperty

Declaration
public static RadProperty SelectionRectangleBorderColorProperty
Field Value
RadProperty

SelectionRectangleColorProperty

Declaration
public static RadProperty SelectionRectangleColorProperty
Field Value
RadProperty

startPoint

Declaration
protected Point startPoint
Field Value
System.Drawing.Point

Properties

AllowArbitraryItemHeight

Gets or sets a value indicating whether the items can have different height.

Declaration
public virtual bool AllowArbitraryItemHeight { get; set; }
Property Value
System.Boolean

AllowArbitraryItemWidth

Gets or sets a value indicating whether the items can have different width.

Declaration
public virtual bool AllowArbitraryItemWidth { get; set; }
Property Value
System.Boolean

DragHint

Gets or sets the RadImageShape instance which describes the hint that indicates where a column will be dropped after a drag operation.

Declaration
[VsbBrowsable(true)]
public RadImageShape DragHint { get; set; }
Property Value
RadImageShape

FindStringComparer

Gets or sets an object that implements IFindStringComparer. The value of this property is used in the keyboard search functionality.

Declaration
public IFindStringComparer FindStringComparer { get; set; }
Property Value
IFindStringComparer

FullRowSelect

Gets or sets a value indicating whether the full row should be selected.

Declaration
public virtual bool FullRowSelect { get; set; }
Property Value
System.Boolean

GroupIndent

Gets or sets the indent of the items when they are displayed in a group.

Declaration
public virtual int GroupIndent { get; set; }
Property Value
System.Int32

GroupItemSize

Gets or sets the default group item size.

Declaration
public Size GroupItemSize { get; set; }
Property Value
System.Drawing.Size

HorizontalScrollState

Gets or sets the display state of the horizontal scrollbar.

Declaration
public ScrollState HorizontalScrollState { get; set; }
Property Value
ScrollState

ItemSize

Gets or sets the default item size.

Declaration
public virtual Size ItemSize { get; set; }
Property Value
System.Drawing.Size

Orientation

Gets or sets the orientation of the view element.

Declaration
public override Orientation Orientation { get; set; }
Property Value
System.Windows.Forms.Orientation

Overrides
Telerik.WinControls.UI.VirtualizedScrollPanel<Telerik.WinControls.UI.ListViewDataItem, Telerik.WinControls.UI.BaseListViewVisualItem>.Orientation

Owner

Gets the RadListViewElement that owns the view.

Declaration
public virtual RadListViewElement Owner { get; }
Property Value
RadListViewElement

ScrollBehavior

Gets the ScrollServiceBehavior that is responsible for the kinetic scrolling option.

Declaration
public ScrollServiceBehavior ScrollBehavior { get; }
Property Value
ScrollServiceBehavior

SelectGroupItems

Determines if the group items can be selected.

Declaration
public bool SelectGroupItems { get; set; }
Property Value
System.Boolean

SelectionRectangleBorderColor

Gets or sets the border color of the lasso selection rectangle.

Declaration
[VsbBrowsable(true)]
public Color SelectionRectangleBorderColor { get; set; }
Property Value
System.Drawing.Color

SelectionRectangleColor

Gets or sets the fill color of the lasso selection rectangle.

Declaration
[VsbBrowsable(true)]
public Color SelectionRectangleColor { get; set; }
Property Value
System.Drawing.Color

VerticalScrollState

Gets or sets the display state of the vertical scrollbar.

Declaration
public ScrollState VerticalScrollState { get; set; }
Property Value
ScrollState

Methods

BeginLassoSelection()

Begins the lasso selection.

Declaration
protected virtual void BeginLassoSelection()

ClearSelection()

Clears the selection.

Declaration
public void ClearSelection()

CreateElementProvider()

Creates the element provider responsible for managing the creation and recycling of visual list view items.

Declaration
protected override IVirtualizedElementProvider<ListViewDataItem> CreateElementProvider()
Returns
IVirtualizedElementProvider<ListViewDataItem>

A new ListViewVirtualizedElementProvider for visual item management.
Overrides
Telerik.WinControls.UI.VirtualizedScrollPanel<Telerik.WinControls.UI.ListViewDataItem, Telerik.WinControls.UI.BaseListViewVisualItem>.CreateElementProvider()

CreateItemTraverser(IList<ListViewDataItem>)

Creates the item traverser responsible for navigating through the list view data items including group support.

Declaration
protected override ITraverser<ListViewDataItem> CreateItemTraverser(IList<ListViewDataItem> items)
Parameters
System.Collections.Generic.IList<ListViewDataItem> items

The collection of ListViewDataItem objects to traverse.
Returns
ITraverser<ListViewDataItem>

A new ListViewTraverser for item navigation.
Overrides
Telerik.WinControls.UI.VirtualizedScrollPanel<Telerik.WinControls.UI.ListViewDataItem, Telerik.WinControls.UI.BaseListViewVisualItem>.CreateItemTraverser(System.Collections.Generic.IList<Telerik.WinControls.UI.ListViewDataItem>)

CreateViewElement()

Creates the view element container responsible for arranging and displaying list view items.

Declaration
protected override VirtualizedStackContainer<ListViewDataItem> CreateViewElement()
Returns
VirtualizedStackContainer<ListViewDataItem>

A new BaseListViewContainer for managing item layout.
Overrides
Telerik.WinControls.UI.ScrollViewElement<Telerik.WinControls.UI.VirtualizedStackContainer<Telerik.WinControls.UI.ListViewDataItem>>.CreateViewElement()

DisposeManagedResources()

Disposes managed resources including timers used for editing, group selection, and lasso operations. Ensures proper cleanup of event handlers and timer resources.

Declaration
protected override void DisposeManagedResources()
Overrides
Telerik.WinControls.UI.VirtualizedScrollPanel<Telerik.WinControls.UI.ListViewDataItem, Telerik.WinControls.UI.BaseListViewVisualItem>.DisposeManagedResources()

EndLassoSelection()

Ends the lasso selection.

Declaration
protected virtual void EndLassoSelection()

EnsureItemVisible(ListViewDataItem)

Ensures that a given ListViewDataItem is visible on the client area.

Declaration
public virtual void EnsureItemVisible(ListViewDataItem item)
Parameters
ListViewDataItem item

The ListViewDataItem to ensure visibility of.

EnsureItemVisible(ListViewDataItem, Boolean)

Ensures that a given ListViewDataItem is visible on the client area.

Declaration
public virtual void EnsureItemVisible(ListViewDataItem item, bool ensureHorizontally)
Parameters
ListViewDataItem item

The ListViewDataItem to ensure visibility of.
System.Boolean ensureHorizontally

Indicates if the view should be scrolled horizontally.

EnsureItemVisibleHorizontal(ListViewDataItem)

Ensures that a given ListViewDataItem is visible by scrolling the view horizontally.

Declaration
protected virtual void EnsureItemVisibleHorizontal(ListViewDataItem item)
Parameters
ListViewDataItem item

The item to ensure visibility of.

EnsureItemVisibleVertical(ListViewDataItem)

Ensures that a given ListViewDataItem is visible by scrolling the view vertically.

Declaration
protected virtual void EnsureItemVisibleVertical(ListViewDataItem item)
Parameters
ListViewDataItem item

The item to ensure visibility of.

EnsureItemVisibleVerticalCore(ListViewDataItem)

Ensures that a given ListViewDataItem is visible when it is below the last visible item in the view.

Declaration
protected virtual void EnsureItemVisibleVerticalCore(ListViewDataItem item)
Parameters
ListViewDataItem item

The item to ensure visibility of.

GetDragHintLocation(BaseListViewVisualItem, Point)

Gets the drag hint location according to the specified item.

Declaration
public virtual Point GetDragHintLocation(BaseListViewVisualItem visualItem, Point mouseLocation)
Parameters
BaseListViewVisualItem visualItem

The drop target item.
System.Drawing.Point mouseLocation

The mouse location in client coordinates.
Returns
System.Drawing.Point

The location of the drag hint.

GetDragHintSize(ISupportDrop)

Gets the size of the drag hint according to the speficied target.

Declaration
public virtual Size GetDragHintSize(ISupportDrop target)
Parameters
ISupportDrop target

The drop target.
Returns
System.Drawing.Size

The size of the drag hint.

GetFirstMatch(String)

This method traverses through the items in the control and fills a queue with these items that start with the searchCriteria.

Declaration
protected virtual ListViewDataItem GetFirstMatch(string searchCriteria)
Parameters
System.String searchCriteria

Returns
ListViewDataItem

GetItemAt(Point)

Gets the ListViewDataItem at a specified location.

Declaration
public ListViewDataItem GetItemAt(Point location)
Parameters
System.Drawing.Point location

The location.
Returns
ListViewDataItem

The ListViewDataItem.

GetItemIndex(ListViewDataItem)

Declaration
protected int GetItemIndex(ListViewDataItem item)
Parameters
ListViewDataItem item

Returns
System.Int32

GetNextItem(ListViewDataItem)

Gets the next visible item of a given ListViewDataItem.

Declaration
protected virtual ListViewDataItem GetNextItem(ListViewDataItem currentItem)
Parameters
ListViewDataItem currentItem

The current item.
Returns
ListViewDataItem

The next item.

GetPreviousItem(ListViewDataItem)

Gets the previous visible item of a given ListViewDataItem.

Declaration
protected virtual ListViewDataItem GetPreviousItem(ListViewDataItem currentItem)
Parameters
ListViewDataItem currentItem

The current item.
Returns
ListViewDataItem

The previous item.

GetVisualItemAt(Point)

Gets the BaseListViewVisualItem at a specified location.

Declaration
public virtual BaseListViewVisualItem GetVisualItemAt(Point location)
Parameters
System.Drawing.Point location

The location.
Returns
BaseListViewVisualItem

The BaseListViewVisualItem.

HandleDeleteKey(KeyEventArgs)

Handles a press of the Delete key.

Declaration
protected virtual void HandleDeleteKey(KeyEventArgs e)
Parameters
System.Windows.Forms.KeyEventArgs e

The event args.

HandleDownKey(KeyEventArgs)

Handles a press of the Down key.

Declaration
protected virtual void HandleDownKey(KeyEventArgs e)
Parameters
System.Windows.Forms.KeyEventArgs e

The event args.

HandleEndKey(KeyEventArgs)

Handles a press of the End key.

Declaration
protected virtual void HandleEndKey(KeyEventArgs e)
Parameters
System.Windows.Forms.KeyEventArgs e

The event args.

HandleEscapeKey(KeyEventArgs)

Handles a press of the Escape key.

Declaration
protected virtual void HandleEscapeKey(KeyEventArgs e)
Parameters
System.Windows.Forms.KeyEventArgs e

The event args.

HandleF2Key(KeyEventArgs)

Handles a press of the F2 key.

Declaration
protected virtual void HandleF2Key(KeyEventArgs e)
Parameters
System.Windows.Forms.KeyEventArgs e

The event args.

HandleHomeKey(KeyEventArgs)

Handles a press of the Home key.

Declaration
protected virtual void HandleHomeKey(KeyEventArgs e)
Parameters
System.Windows.Forms.KeyEventArgs e

The event args.

HandleLeftKey(KeyEventArgs)

Handles a press of the Left key.

Declaration
protected virtual void HandleLeftKey(KeyEventArgs e)
Parameters
System.Windows.Forms.KeyEventArgs e

The event args.

HandleNavigation(Char)

Handles navigation upon key press.

Declaration
protected virtual void HandleNavigation(char keyChar)
Parameters
System.Char keyChar

The character of the pressed key.

HandlePageDownKey(KeyEventArgs)

Handles a press of the PageDown key.

Declaration
protected virtual void HandlePageDownKey(KeyEventArgs e)
Parameters
System.Windows.Forms.KeyEventArgs e

The event args.

HandlePageUpKey(KeyEventArgs)

Handles a press of the PageUp key.

Declaration
protected virtual void HandlePageUpKey(KeyEventArgs e)
Parameters
System.Windows.Forms.KeyEventArgs e

The event args.

HandleRightKey(KeyEventArgs)

Handles a press of the Right key.

Declaration
protected virtual void HandleRightKey(KeyEventArgs e)
Parameters
System.Windows.Forms.KeyEventArgs e

The event args.

HandleSpaceKey(KeyEventArgs)

Handles a press of the Space key.

Declaration
protected virtual void HandleSpaceKey(KeyEventArgs e)
Parameters
System.Windows.Forms.KeyEventArgs e

The event args.

HandleUpKey(KeyEventArgs)

Handles a press of the Up key.

Declaration
protected virtual void HandleUpKey(KeyEventArgs e)
Parameters
System.Windows.Forms.KeyEventArgs e

The event args.

InitializeFields()

Initializes the fields and properties specific to the BaseListViewElement. Configures default values and initializes the find string comparer for keyboard search functionality.

Declaration
protected override void InitializeFields()
Overrides
Telerik.WinControls.UI.ScrollViewElement<Telerik.WinControls.UI.VirtualizedStackContainer<Telerik.WinControls.UI.ListViewDataItem>>.InitializeFields()

OnLassoTimerTick(Object, EventArgs)

Declaration
protected virtual void OnLassoTimerTick(object sender, EventArgs e)
Parameters
System.Object sender

System.EventArgs e

OnOrientationChanged()

Called when the orientation of the view has changed.

Declaration
protected virtual void OnOrientationChanged()

OnPropertyChanged(RadPropertyChangedEventArgs)

Handles property change events and updates the view when display-related properties change. Refreshes the view for properties affecting layout and appearance.

Declaration
protected override void OnPropertyChanged(RadPropertyChangedEventArgs e)
Parameters
RadPropertyChangedEventArgs e

The RadPropertyChangedEventArgs containing property change information.
Overrides

OnScrollerUpdated()

Declaration
protected virtual void OnScrollerUpdated()

PaintOverride(IGraphics, Rectangle, Single, SizeF, Boolean)

Performs custom painting operations including rendering the lasso selection rectangle when active. Draws the selection rectangle with specified fill and border colors during drag selection.

Declaration
protected override void PaintOverride(IGraphics screenRadGraphics, Rectangle clipRectangle, float angle, SizeF scale, bool useRelativeTransformation)
Parameters
IGraphics screenRadGraphics

The graphics context for painting operations.
System.Drawing.Rectangle clipRectangle

The clipping rectangle to constrain painting.
System.Single angle

The rotation angle for painting transformations.
System.Drawing.SizeF scale

The scaling factor for painting transformations.
System.Boolean useRelativeTransformation

Whether to use relative transformation during painting.
Overrides

ProcessDragOver(Point, ISupportDrag)

Processes drag over events to determine whether drag-drop operations are allowed.

Declaration
protected override bool ProcessDragOver(Point mousePosition, ISupportDrag dragObject)
Parameters
System.Drawing.Point mousePosition

The current mouse position during the drag operation.
ISupportDrag dragObject

The object being dragged that implements ISupportDrag.
Returns
System.Boolean

True if drag-drop is allowed based on the owner's AllowDragDrop setting; otherwise, false.
Overrides

ProcessItemLassoSelection(ListViewDataItem, Boolean)

Declaration
protected virtual void ProcessItemLassoSelection(ListViewDataItem currentItem, bool isIntersecting)
Parameters
ListViewDataItem currentItem

System.Boolean isIntersecting

ProcessKeyDown(KeyEventArgs)

Processes the KeyDown event.

Declaration
protected virtual bool ProcessKeyDown(KeyEventArgs e)
Parameters
System.Windows.Forms.KeyEventArgs e

The event args.
Returns
System.Boolean

true if the processing of the event should be stopped, false otherwise.

ProcessKeyPress(KeyPressEventArgs)

Declaration
protected virtual bool ProcessKeyPress(KeyPressEventArgs e)
Parameters
System.Windows.Forms.KeyPressEventArgs e

Returns
System.Boolean

ProcessLassoSelection()

Selects all items that are whitin the lasso rectangle.

Declaration
protected void ProcessLassoSelection()

ProcessLassoSelection(Rectangle)

Selects all items that are whitin the specified rectangle.

Declaration
protected virtual void ProcessLassoSelection(Rectangle selectionRect)
Parameters
System.Drawing.Rectangle selectionRect

ProcessMouseDown(MouseEventArgs)

Processes the MouseDown event.

Declaration
protected virtual bool ProcessMouseDown(MouseEventArgs e)
Parameters
System.Windows.Forms.MouseEventArgs e

The event args.
Returns
System.Boolean

true if the processing of the event should be stopped, false otherwise.

ProcessMouseMove(MouseEventArgs)

Processes the MouseMove event.

Declaration
protected virtual bool ProcessMouseMove(MouseEventArgs e)
Parameters
System.Windows.Forms.MouseEventArgs e

The event args.
Returns
System.Boolean

true if the processing of the event should be stopped, false otherwise.

ProcessMouseUp(MouseEventArgs)

Processes the MouseUp event.

Declaration
protected virtual bool ProcessMouseUp(MouseEventArgs e)
Parameters
System.Windows.Forms.MouseEventArgs e

The event args.
Returns
System.Boolean

true if the processing of the event should be stopped, false otherwise.

ProcessMouseWheel(MouseEventArgs)

Processes the MouseWheel event.

Declaration
protected virtual bool ProcessMouseWheel(MouseEventArgs e)
Parameters
System.Windows.Forms.MouseEventArgs e

The event args.
Returns
System.Boolean

true if the processing of the event should be stopped, false otherwise.

ProcessSelection(ListViewDataItem, Keys, Boolean)

Processes the selection of a specified item.

Declaration
protected virtual void ProcessSelection(ListViewDataItem item, Keys modifierKeys, bool isMouseSelection)
Parameters
ListViewDataItem item

The ListViewDataItem which is being processed.
System.Windows.Forms.Keys modifierKeys

The modifier keys which are pressed during selection.
System.Boolean isMouseSelection

[true] if the selection is triggered by mouse input, [false] otherwise.

ScrollTo(Int32)

Scrolls the view with a given amount.

Declaration
public void ScrollTo(int delta)
Parameters
System.Int32 delta

The amount to scroll with.

SetScrollValue(RadScrollBarElement, Int32)

Declaration
protected void SetScrollValue(RadScrollBarElement scrollbar, int newValue)
Parameters
RadScrollBarElement scrollbar

System.Int32 newValue

ShouldDropAfter(BaseListViewVisualItem, Point)

Indicates whether an item should be dropped after the given target according to the specified location.

Declaration
public virtual bool ShouldDropAfter(BaseListViewVisualItem targetElement, Point dropLocation)
Parameters
BaseListViewVisualItem targetElement

The drop target item.
System.Drawing.Point dropLocation

The drop location.
Returns
System.Boolean

[true] if a dropped item should be inserted after the target, [false] otherwise.

SupportsOrientation(Orientation)

Returns a value indicating whether the current view supports given orientation.

Declaration
protected virtual bool SupportsOrientation(Orientation orientation)
Parameters
System.Windows.Forms.Orientation orientation

The orientation.
Returns
System.Boolean

[true] if the current view supports the orientation, [false] otherwise.

ToggleItemCheckState(ListViewDataItem)

Toggles the CheckState of given item.

Declaration
protected void ToggleItemCheckState(ListViewDataItem item)
Parameters
ListViewDataItem item

The item whose CheckState will be toggled.

UpdateHScrollbarMaximum()

Updates the horizontal scrollbar.

Declaration
public virtual void UpdateHScrollbarMaximum()

UpdateHScrollbarVisibility()

Updates the visibility of the horizontal scrollbar.

Declaration
protected virtual void UpdateHScrollbarVisibility()

UpdateOnMeasure(SizeF)

Updates the view layout during measure operations, handling scrollbar visibility and client rectangle calculations. Configures horizontal scrollbar properties and updates maximum scroll values.

Declaration
protected override bool UpdateOnMeasure(SizeF availableSize)
Parameters
System.Drawing.SizeF availableSize

The available size for layout measurement.
Returns
System.Boolean

True if the view was updated; otherwise, false.
Overrides
Telerik.WinControls.UI.VirtualizedScrollPanel<Telerik.WinControls.UI.ListViewDataItem, Telerik.WinControls.UI.BaseListViewVisualItem>.UpdateOnMeasure(System.Drawing.SizeF)

Extension Methods