COM Event Handlers

Use registerevent to register server events. Use events to list all the events a COM object recognizes.

Arguments Passed to Event Handlers

When a registered event is triggered, MATLAB^® passes information from the event to its handler function, as shown in the following table.

Arguments Passed by MATLAB Functions

Arg. No.	Contents	Format
1	Object name	MATLAB COM class
2	Event ID	double
3	Start of Event Argument List	As passed by the control
end-2	End of Event Argument List (Argument N)	As passed by the control
end-1	Event Structure	structure
end	Event Name	char array

When writing an event handler function, use the Event Name argument to identify the source of the event. Get the arguments passed by the control from the Event Argument List (arguments 3 through end-2). All event handlers must accept a variable number of arguments:

function event (varargin)
if (strcmp(varargin{end}, 'MouseDown'))  % Check the event name
    x_pos = varargin{5};              % Read 5th Event Argument
    y_pos = varargin{6};              % Read 6th Event Argument
end

Note

The values passed vary with the particular event and control being used.

Event Structure

The Event Structure argument passed by MATLAB contains the fields shown in the following table.

Fields of the Event Structure

Field Name	Description	Format
Type	Event Name	char array
Source	Control Name	MATLAB COM class
EventID	Event Identifier	double
Event Arg Name 1	Event Arg Value 1	As passed by the control
Event Arg Name 2	Event Arg Value 2	As passed by the control
etc.	Event Arg N	As passed by the control