Enum MessageDirection

pub enum MessageDirection {
    ToWidget,
    FromWidget,
}

Message direction allows you to distinguish from where message has came from. Often there is a need to find out who created a message to respond properly. Imagine that we have a NumericUpDown input field for a property and we using some data source to feed data into input field. When we change something in the input field by typing, it creates a message with new value. On other hand we often need to put new value in the input field from some code, in this case we again creating a message. But how to understand from which “side” message has came from? Was it filled in by user and we should create a command to change value in the data source, or it was created from syncing code just to pass new value to UI? This problem solved by setting a direction to a message. Also it solves another problem: often we need to respond to a message only if it did some changes. In this case at first we fire a message with ToWidget direction, widget catches it and checks if changes are needed and if so, it “rethrows” message with direction FromWidget. Listeners are “subscribed” to FromWidget messages only and won’t respond to ToWidget messages.

Variants

ToWidget

Used to indicate a request for changes in a widget.

FromWidget

Used to indicate response from widget if anything has actually changed.

Implementations

impl MessageDirection

pub fn reverse(self) -> MessageDirection

Reverses direction.

Trait Implementations

impl Clone for MessageDirection

fn clone(&self) -> MessageDirection

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for MessageDirection

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl Hash for MessageDirection

fn hash<__H>(&self, state: &mut __H)

where __H: Hasher,

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for MessageDirection

fn eq(&self, other: &MessageDirection) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialOrd for MessageDirection

fn partial_cmp(&self, other: &MessageDirection) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl Copy for MessageDirection

impl Eq for MessageDirection

impl StructuralPartialEq for MessageDirection