How to set selected datatable rows from managed bean with primefaces datatable

Question

I have a primefaces datatable with a multiple selection column. I want to be able to set the selected (checked) rows upon load. I will have the desired selected rows from a service call in the post construct, but I need to know where to pass those values so when the page loads, it checks certain rows.

Answer 1

for example:

<p:dataTable id="mainDataTable" var="pm" widgetVar="dt" 
                value="#{generarPreMatriculaBean.preMatriculas}" rowKey="#{pm.id}"              
                selection="#{generarPreMatriculaBean.preMatriculasSelec}" 
                styleClass="datatable_style_general" scrollable="true"
                rowIndexVar="rowIndex"
                emptyMessage="No se encontró registros" 
                rowStyleClass="#{pm.generado == true ? 'old' : null}">

for set selection you have to init property preMatriculasSelec when you are in INIT METHOD OF BEAN:

@PostConstruct
    public void init(){
    preMatriculasSelec = something;
}

And selection will be checked on view.