Struct EventBuilder

pub struct EventBuilder { /* private fields */ }

Builder for creating Event metadata entries.

EventBuilder provides a fluent API for creating Event table entries with validation and automatic heap management. Event entries define notification mechanisms that enable objects to communicate state changes and important occurrences to observers using type-safe delegate handlers.

Event Model

.NET events follow a standard pattern with:

• Event Declaration: Name, attributes, and delegate type
• Add Accessor: Method to subscribe to the event
• Remove Accessor: Method to unsubscribe from the event
• Raise Accessor: Optional method to trigger the event
• Other Accessors: Additional event-related methods

Method Association

Events are linked to their implementation methods through the MethodSemantics table (created separately):

• Add Method: Subscribes handlers to the event
• Remove Method: Unsubscribes handlers from the event
• Raise Method: Triggers the event (optional)
• Other Methods: Additional event-related operations

Examples

let assembly = CilAssembly::new(view);
let mut context = BuilderContext::new(assembly);

// Create a coded index for System.EventHandler delegate type
let event_handler_type = CodedIndex::new(TableId::TypeRef, 1); // TypeRef to EventHandler

// Create a standard event
let click_event = EventBuilder::new()
    .name("Click")
    .flags(0x0000) // No special flags
    .event_type(event_handler_type.clone())
    .build(&mut context)?;

// Create an event with special naming
let special_event = EventBuilder::new()
    .name("PropertyChanged")
    .flags(0x0200) // SpecialName
    .event_type(event_handler_type)
    .build(&mut context)?;

Implementations

impl EventBuilder

pub fn new() -> Self

Creates a new EventBuilder.

Returns

A new crate::metadata::tables::event::EventBuilder instance ready for configuration.

pub fn name(self, name: impl Into<String>) -> Self

Sets the event name.

Event names are used for reflection, debugging, and binding operations. Common naming patterns include descriptive verbs like “Click”, “Changed”, “Loading”, or property names with “Changed” suffix for property notifications.

Arguments

• name - The event name (must be a valid identifier)

Returns

Self for method chaining.

pub fn flags(self, flags: u32) -> Self

Sets the event flags (attributes).

Event flags control special behaviors and characteristics. Common flag values from EventAttributes:

• 0x0000: No special flags (default for most events)
• 0x0200: SPECIAL_NAME - Event has special naming conventions
• 0x0400: RTSPECIAL_NAME - Runtime provides special behavior based on name

Arguments

• flags - The event attribute flags bitmask

Returns

Self for method chaining.

pub fn event_type(self, event_type: CodedIndex) -> Self

Sets the event handler delegate type.

The event type defines the signature for event handlers that can be subscribed to this event. This must be a delegate type that specifies the parameters passed to event handlers when the event is raised.

Common delegate types:

• System.EventHandler - Standard parameterless event handler
• System.EventHandler<T> - Generic event handler with typed event args
• Custom delegate types for specialized event signatures

Arguments

• event_type - A TypeDefOrRef coded index pointing to the delegate type

Returns

Self for method chaining.

pub fn build(self, context: &mut BuilderContext) -> Result<Token>

Builds the event and adds it to the assembly.

This method validates all required fields are set, adds the name to the string heap, creates the raw event structure, and adds it to the Event table.

Note: This only creates the Event table entry. Method associations (add, remove, raise) must be created separately using MethodSemantics builders.

Arguments

• context - The builder context for managing the assembly

Returns

A crate::metadata::token::Token representing the newly created event, or an error if validation fails or required fields are missing.

Errors

• Returns error if name is not set
• Returns error if flags are not set
• Returns error if event_type is not set
• Returns error if heap operations fail
• Returns error if table operations fail

Trait Implementations

impl Default for EventBuilder

fn default() -> Self

Returns the “default value” for a type.