BlockPropertyAction<T> Class

Definition

Namespace:Avalonia.Controls.Documents.Primitives.Actions

Assembly:Avalonia.Controls.RichTextEditor

Package:Avalonia.Controls.RichTextEditor

Base class for block-level property actions.

public class BlockPropertyAction<T>

Inheritance: object -> EditorAction -> BlockPropertyAction<T>

Implements: IBlockPropertyAction, IBlockPropertyAction<>, IEditorAction, IPropertyAction, IPropertyAction<>

Remarks

This base class provides common functionality for actions that modify properties on Block elements (Paragraph, Section, etc.).

When the selection spans multiple blocks, all affected blocks have their property set. Override Avalonia.Controls.Documents.Primitives.Actions.BlockPropertyAction<T>.ResolveTargetElements(Avalonia.Controls.Documents.Primitives.ITextEditorHost) to change the set of elements that are modified (e.g. target Avalonia.Controls.Documents.TableCell instead of Avalonia.Controls.Documents.Paragraph).

Derived classes only need to:

• Specify the target StyledProperty
• Provide metadata (Id, DisplayName, Gesture)
• Return available values if applicable

Methods

Name	Description
CanExecute	Gets whether the action can currently execute.
ClearValue	Clears the property value for the selection, reverting affected elements to their inherited or default value.
Execute	Executes the action synchronously.
ExecuteAsync	Executes the action asynchronously. Inherited from EditorAction.
GetAvailableValues	No summary available.
GetState	Gets the current state of the action.
GetValue	No summary available.
HasConsistentValue	Gets whether all affected blocks have the same value for this property.
SetValue	No summary available.

CanExecute Method

Gets whether the action can currently execute.

public bool CanExecute(Avalonia.Controls.Documents.Primitives.ITextEditorHost host)

Parameters

host Avalonia.Controls.Documents.Primitives.ITextEditorHost

The editor host to check against.

Returns

bool

True if the action can execute; otherwise, false.

Remarks

This is called frequently to update UI state (button enabled/disabled). Implementations should be fast and avoid heavy computation.

ClearValue Method

Clears the property value for the selection, reverting affected elements to their inherited or default value.

public void ClearValue(Avalonia.Controls.Documents.Primitives.ITextEditorHost host)

Parameters

host Avalonia.Controls.Documents.Primitives.ITextEditorHost

The editor host to modify.

Execute Method

Executes the action synchronously.

public void Execute(Avalonia.Controls.Documents.Primitives.ITextEditorHost host)

Parameters

host Avalonia.Controls.Documents.Primitives.ITextEditorHost

The editor host to execute on.

Remarks

A property action carries no value of its own, so plain invocation does nothing: the value arrives through Avalonia.Controls.Documents.Primitives.Actions.BlockPropertyAction<T>.SetValue(Avalonia.Controls.Documents.Primitives.ITextEditorHost,`0) from the picker bound to the action. This matches Avalonia.Controls.Documents.Primitives.Actions.PropertyAction<T>.Execute(Avalonia.Controls.Documents.Primitives.ITextEditorHost). The member is on Avalonia.Controls.Documents.Primitives.Actions.IEditorAction and therefore reachable from any tool, including a Avalonia.Controls.Documents.Primitives.Toolbar.ButtonTool a consumer binds to EditorActions.Margin; a no-op leaves that button inert instead of faulting the click handler's task.

GetAvailableValues Method

public System.Collections.Generic.IEnumerable<T> GetAvailableValues()

Returns

System.Collections.Generic.IEnumerable<T>

GetState Method

Gets the current state of the action.

public object GetState(Avalonia.Controls.Documents.Primitives.ITextEditorHost host)

Parameters

host Avalonia.Controls.Documents.Primitives.ITextEditorHost

The editor host to query.

Returns

object

The current state, or null if the action has no state. A toggle action returns a boolean, a property action the current value.

Remarks

Read Avalonia.Controls.Documents.Primitives.Actions.IToggleAction.IsChecked(Avalonia.Controls.Documents.Primitives.ITextEditorHost) or Avalonia.Controls.Documents.Primitives.Actions.IPropertyAction.GetValueAsObject(Avalonia.Controls.Documents.Primitives.ITextEditorHost) instead. Both say which family the value came from, which an untyped object cannot.

GetValue Method

public T GetValue(Avalonia.Controls.Documents.Primitives.ITextEditorHost host)

Parameters

host Avalonia.Controls.Documents.Primitives.ITextEditorHost

Returns

T

HasConsistentValue Method

Gets whether all affected blocks have the same value for this property.

public bool HasConsistentValue(Avalonia.Controls.Documents.Primitives.ITextEditorHost host)

Parameters

host Avalonia.Controls.Documents.Primitives.ITextEditorHost

The editor host.

Returns

bool

True if all affected blocks have the same property value. False if blocks have different values (mixed state).

Remarks

UI controls should show a mixed/indeterminate state when this returns false. For example, a ComboBox might show "Mixed" placeholder text.

For collapsed selections, this always returns true (single block).

SetValue Method

public void SetValue(Avalonia.Controls.Documents.Primitives.ITextEditorHost host, T value)

Parameters

host Avalonia.Controls.Documents.Primitives.ITextEditorHost

value T

Properties

Name	Description
DisplayName	Gets the display name for UI purposes. Inherited from EditorAction.
Gesture	Gets the optional keyboard gesture for this action. Inherited from EditorAction.
Id	Gets the unique identifier for this action. Inherited from EditorAction.