如何让extjs组合框像普通的html选择框一样工作?

在实例化Ext.form.ComboBox对象时,只需使用适当的配置即可获得该行为:

var selectStyleComboboxConfig = {
    fieldLabel: 'My Dropdown',
    name: 'type',
    allowBlank: false,
    editable: false,
    // This is the option required for "select"-style behaviour
    triggerAction: 'all',
    typeAhead: false,
    mode: 'local',
    width: 120,
    listWidth: 120,
    hiddenName: 'my_dropdown',
    store: [
        ['val1', 'First Value'],
        ['val2', 'Second Value']
    ],
    readOnly: true
};
var comboBox = new Ext.form.ComboBox(selectStyleComboboxConfig); 

替换 mode: 'local' store 如果你想把它绑定到一个 Ext.data.JsonStore

{
    xtype: 'combo',
    fieldLabel: 'Price',
    name: 'price',
    hiddenName: 'my_dropdown',
    autoSelect: false,
    allowBlank: false,
    editable: false,
    triggerAction: 'all',
    typeAhead: true,
    width:120,
    listWidth: 120,
    enableKeyEvents: true,
    mode: 'local',
    store: [
        ['val1', 'Appaloosa'],
        ['val2', 'Arabian'],
        ['val3', 'Clydesdale'],
        ['val4', 'Paint'],
        ['val5', 'Palamino'],
        ['val6', 'Quarterhorse'],
    ],
    listeners: {
        keypress: function(comboBoxObj, keyEventObj) {
            // Ext.Store names anonymous fields (like in array above) "field1", "field2", etc.
            var valueFieldName = "field1";
            var displayFieldName = "field2";

            // Which drop-down item is already selected (if any)?
            var selectedIndices = this.view.getSelectedIndexes();
            var currentSelectedIndex = (selectedIndices.length > 0) ? selectedIndices[0] : null;

            // Prepare the search criteria we'll use to query the data store
            var typedChar = String.fromCharCode(keyEventObj.getCharCode());
            var startIndex = (currentSelectedIndex == null) ? 0 : ++currentSelectedIndex;

            var matchIndex = this.store.find(displayFieldName, typedChar, startIndex, false);

            if( matchIndex >= 0 ) {
                this.select(matchIndex);
            } else if (matchIndex == -1 && startIndex > 0) {
                // If nothing matched but we didn't start the search at the beginning of the list
                // (because the user already had somethign selected), search again from beginning.
                matchIndex = this.store.find(displayFieldName, typedChar, 0, false);                                
                if( matchIndex >= 0 ) {
                    this.select(matchIndex);
                }
            }

            if( matchIndex >= 0 ) {
                var record = this.store.getAt(matchIndex);
                this.setValue(record.get(valueFieldName));
            }
        }
    }
}

你试过了吗 typeAhead = false ? 不太确定这是否接近你想要的。

var combo = new Ext.form.ComboBox({
    typeAhead: false,

    ...

});

var buf = []; 
buf.push('<option>aA1</option>');
buf.push('<option>aA2</option>');
buf.push('<option>bA3</option>');
buf.push('<option>cA4</option>');

var items = buf.join('');
new Ext.Component({
    renderTo: Ext.getBody(),
    autoEl: {
         tag:'select',
         cls:'x-font-select',
         html: items
    }
 });

只用 Ext.merge 功能

http://docs.sencha.com/extjs/4.2.1/#!/api/Ext-method-merge