问组合框ExtJs的不需要行为

EN

var bik = new Ext.form.ComboBox({
    [...],

    // Check if query is queued or in progress
    isLoading: function() {
        return this.isStoreLoading || // check if store is making ajax request
            this.isQueryPending; // check if there is any query pending
    },

    // This is responsible for finding matching record in store
    assertValue: function() {
        if (this.isLoading()) {
            this.assertionRequired = true;
            return;
        }

        Ext.form.ComboBox.prototype.assertValue.apply(this, arguments);
    },

    // this is private method; you can equally write 'beforeload' event handler for store
    onBeforeLoad: function(){
        this.isQueryPending = false;
        this.isStoreLoading = true;

        Ext.form.ComboBox.prototype.onBeforeLoad.apply(this, arguments);
    },

    // catch moment when query is added to queue
    onKeyUp: function(e){
        var k = e.getKey();
        if(this.editable !== false && this.readOnly !== true && (k == e.BACKSPACE || !e.isSpecialKey())){
            this.isQueryPending = true;
        }

        Ext.form.ComboBox.prototype.onKeyUp.apply(this, arguments);
    },

    // this is private method; you can equally write 'load' event handler for store
    onLoad: function() {
        Ext.form.ComboBox.prototype.onLoad.apply(this, arguments);

        this.isQueryPending = false;
        this.isStoreLoading = false;
        if (this.assertionRequired === true) {
            delete this.assertionRequired;
            this.assertValue();
        }
    }
});