Class BindingExtension

Namespace

Icy.Markup.Extensions

Assembly

IcyUI.dll

{Binding ...}: binds a property to a path evaluated against an explicit source, a named element, or

• the common case - the target's DataContext.

[MarkupExtensionDefaultProperty("Path")]
public sealed class BindingExtension : IMarkupExtension

Inheritance

object

BindingExtension

Implements

IMarkupExtension

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.ReferenceEquals(object, object)

object.ToString()

Extension Methods

PropertyReferencesExtensions.ContainsProperty(object, IPropertyReference)

Remarks

{Binding Path=Name} can be shortened to {Binding Name} - Path is this extension's default property. {Binding} with no path at all binds the whole source object.

Binding to a property the property-registry marks non-bindable (AsTarget, or IsBindable) is an error, not a silent no-op - raised by TargetProperty itself, which this extension assigns through unchanged.

Always resolves to Unset: the binding is applied to the target directly (and, for the implicit-DataContext case, re-applied whenever DataContextChanged fires), so there is never a single value for the loader to assign afterward.

A path is static (resolved once on a known type), compiled (see Compiled), or dynamic (resolved on each read) when the source type is unknown; see the Data binding concept page.

Properties

Compiled

Gets or sets a value indicating whether the path is compiled into delegates (CompiledPropertyPath) instead of read through reflection.

public bool Compiled { get; set; }

Property Value

bool

Remarks

Needs a known source type: an x:DataType on this element or an ancestor for a data-context binding, or ElementName or Source. Without one, the markup fails to load.

A compiled data-context binding throws BindingException when the data context isn't the x:DataType; a static one warns and falls back to a dynamic path. Under NativeAOT, compiled paths are interpreted, at about the speed of static ones.

A path that reads a member of a property typed object (such as SelectedItem.Name) can't be compiled: the member is only known at run time. Such a path is read dynamically even with Compiled set, without an error.

ElementName

Gets or sets the x:Name of the element to bind to, instead of the target's DataContext.

public string? ElementName { get; set; }

Property Value

string

Mode

Gets or sets the binding's direction. Unset keeps the target property's own default (see DefaultTwoWayBinding).

public BindingMode? Mode { get; set; }

Property Value

BindingMode?

Path

Gets or sets the path, relative to the source, to bind to. Unset (or empty) binds the source itself.

public string? Path { get; set; }

Property Value

string

Source

Gets or sets the object to bind to directly, instead of the target's DataContext.

public object? Source { get; set; }

Property Value

object

UpdateTargetTrigger

Gets or sets when the binding refreshes the target from the source. See UpdateTargetTrigger.

public UpdateTargetTrigger UpdateTargetTrigger { get; set; }

Property Value

UpdateTargetTrigger

Methods

ProvideValue(MarkupExtensionContext)

Computes the value the loader should use.

public object? ProvideValue(MarkupExtensionContext context)

Parameters

context MarkupExtensionContext

The property being resolved, and what the loader knows about the document.

Returns

object

The value to assign, converted the same way an ordinary attribute value would be; or Unset when the extension already applied its own effect (typically by binding the property itself) and nothing further should be assigned.

Exceptions

MarkupException

One of the following:

• the target doesn't support bindings;
• the property isn't a registered one;
• ElementName names nothing in scope;
• the property is marked non-bindable;
• the source type is known (an x:DataType, ElementName or Source) and Path doesn't resolve on it;
• Compiled is set without a known source type.