change ViewModel dynamically

The following code words great:

Code:

...
  session: true,
    initComponent: function () {
           var me = this;
           me.setViewModel({ data: { foo: { RowNo: 945 } } });
           this.callParent();
}
...

But if I want to dynamically change this ViewModel data at runtime event(like selectionChange event) , nothing will be happend. for example :

Code:

...
  session: true,
    initComponent: function () {
           var me = this;
           me.setViewModel({ data: { foo: { RowNo: 945 } } });
           me.on('selectionchanged',function(record){
                  me.setViewModel({ data: { foo: { RowNo: 888 /*or something from record */} } });
           });

           this.callParent();
}
...

can you help me if I did something wrong?