I fixed it with on change client script.

function onChange(control, oldValue, newValue, isLoading) {
if (isLoading || newValue == '') {

return;
}
if (newValue == 'true') {

g_form.setValue("vabc_zxy", "c477ca52db2428101422fbf4e296196b,0db74e52db2428101422fbf4e29619f0,1cd7ce52db2428101422fbf4e29619cc,29080a52db2428101422fbf4e2961975,97e7c612db2428101422fbf4e296192e,e4384e12db2428101422fbf4e2961940,eb18ce52db2428101422fbf4e29619d2", "Abc, Def, Ghy, BCA, BBH, CVF, CVX");

} else
g_form.clearValue('vabc_zxy');

}