gistfile1.txt

Ext.ns('IbwUi.controls');

IbwUi.controls.ComboBoxJSON = Ext.extend(Ext.form.ComboBox, {

    url: '',
    root: '',
    valueField: 'id',
    displayField: 'name',
    listWidth: 200,
    width: 200,


    initComponent: function () {

	   	var comboStoreJson = new Ext.data.JsonStore({
			   idProperty: 'id',
               autoDestroy: true,
			   autoLoad: true,
	           root: this.root,
	           fields: this.fields || [
                   { name: 'id', type: 'int' }, 
                   { name: 'name', type: 'string' }
               ],
               sortInfo: {
                   field: this.displayField,
                   direction: 'ASC'
               },
	           proxy: new Ext.data.ScriptTagProxy({
	               api: {
	                   read: this.url
	               }
	           })
	       });
           
        var config = {
            autoSelect: true,
            store: comboStoreJson,
            displayField: this.displayField,
            valueField: this.valueField,
            mode: 'remote',
            forceSelection: true,
			minChars: 1,
            triggerAction: 'all',
            lastQuery: '',
			typeAhead: true,
            typeAheadDelay: 50,
			lazyRender: true,
            lastQuery: '',
			value: this.value,
            listWidth: this.width + 200,
			width: this.width
        };

        Ext.apply(this, config);

        IbwUi.controls.ComboBoxJSON.superclass.initComponent(this);
        
        this.on('beforeselect', function() {
           
                       
        })

    }
});

Ext.reg("ibwComboJson", IbwUi.controls.ComboBoxJSON);