Invoke a callback by way of an annotation click function. This example shows how to change a parameter value on a block to the value shown on an annotation.

Open vdp. Add and position two annotations. Each annotation displays a different value.

open_system('vdp');
an1 = Simulink.Annotation('vdp/1');
an1.position = [100,300];
an2 = Simulink.Annotation('vdp/3');
an2.position = [150,300];

Assign a click function to each annotation. The click function uses getAnnotationCallback to get the annotation instance. Get the text from each annotation and use it to set the parameter on the Gain block (Mu).

an1.ClickFcn = 'ann = getCallbackAnnotation; v = ann.Text; set_param(''vdp/Mu'',''Gain'',v)';
an2.ClickFcn = 'ann = getCallbackAnnotation; v = ann.Text; set_param(''vdp/Mu'',''Gain'',v)';

Click each annotation. When you click, the gain value on the Mu block changes to the number shown on the annotation.