Extjs: Two Way Binding Between Grid & Form

I am trying to learn ExtJS and am sort of stuck at a place. I want to create a screen with a grid on top and a form at the bottom. I want to bind them both with each other so that

Solution 1:

Try this example:

Ext.widget('container',{
        width: 600,
        hight: 800,
        renderTo: Ext.getBody(),
        viewModel: {
            formulas: {
                selection: {
                    bind: '{g.selection}',
                    get: function(selection){
                        return selection;
                    }
                }
            }
        },
        items: [
            {
                xtype: 'grid',
                title: 'Grid',
                reference: 'g',
                store: {
                    type: 'store',
                    fields: ['id', 'name'],
                    data: [{id: 1, name: 'foo'}, {id: 2, name: 'bar'}]
                },
                columns: [
                    {dataIndex: 'id', header: 'ID'},
                    {dataIndex: 'name', header: 'Name'}
                ]
            },
            {
                xtype: 'form',
                title: 'Form',
                items: [
                    {
                        xtype: 'displayfield',
                        fieldLabel: 'ID',
                        bind: '{selection.id}'
                    },
                    {
                        xtype: 'textfield',
                        fieldLabel: 'Name',
                        bind: '{selection.name}'
                    }
                ],
                bind: {
                    hidden: '{!selection}'
                }
            }
        ]

    });

https://fiddle.sencha.com/#fiddle/179d