How to add an empty item to ExtJS combobox?

Question

I want to add and empty item (display value is blank, item height is kept as normal) to an Ext.form.ComboBox. I refered 2 links below to configure my combobox, but it still not display the empty item:

• http://www.ashlux.com/wordpress/2009/09/04/handling-empty-options-with-ext-js-combo-box/
• http://www.sencha.com/forum/showthread.php?52340-How-to-add-a-quot-blank-quot-entry-to-a-ComboBox

Here is my code:

this.abcCombo = new Ext.form.ComboBox({
    name : 'abcCombo',
    hiddenName : 'abcCombo-id',
    fieldLabel : "My Combobox",
    width : 250,
    editable : false,
    forceSelection : true,
    mode : 'local',
    triggerAction : 'all',
    valueField : 'id',
    displayField : 'fullName',
    store : new Ext.data.JsonStore({
        fields : ['id', 'fullName']
    }),
    tpl : '<tpl for="."><div class="x-combo-list-item">{fullName}&nbsp;</div></tpl>'
});

The combobox store's data will be loaded after an Ajax request (i.e 3 items in data items). And the combobox has only 3 item (not 4 as I expected). Do you have any idea about my problem?! Thank you so much!

Answer 1

This is what worked for me I tried putting ' ' into the field that I had set as the display field for the combo box on the model that I wanted to show up blank that worked in the drop down of the combo box but not in the text box after it's been selected it would show ' ' which I didn't want. So, I used the displayTpl config on my combo box which affects the text box shown after selecting something in a combo.

This is my model that I added to the store attached to the combo box and the displayField is contactName.

var blankModel = Ext.create('myefiles.jobs.pdd.model.Contact', {
    id: null,
    contactName: ' ',
    tel: null,
    cell: null,
    email: null,
    vendorUUID: null,
    vendorName: null,
    active: null,
    deleted: null
});

This is the displayTpl config on my combobox

displayTpl: Ext.create('Ext.XTemplate',
   '<tpl for=".">',
      '<tpl switch="contactName">',
         '<tpl case="&nbsp;">',
         '<tpl default>{contactName}',
      '</tpl>',
   '</tpl>'
)

This probably could be done with an if statement instead of the switch thing I did but I'll be honest I have never worked with XTemplates and I don't know what I'm doing also I had an example of a switch statement and got it to work so. I'm basically just saying if the contactName = ' ' then don't put anything and if its anything else display the contactName.

Answer 2

This is how we can add a blank field in Combo box

In java Map or any other collection put key value like this

fuelMap.put(""," "); // we need to add " " not ""," " or null 
                          // because these will add a fine blank line in Combobox 
                          // which will be hardly noticeable.

In js file, it should be like this :

Listener for combo box

listeners: {
    select: function (comp, record, index) {
        if (comp.getValue() === "" || comp.getValue() === " ") {
            comp.setValue(null);
        }
    }
}

Answer 3

If the store uses inline data then store.load even won't fire. Maybe there is a better solution, but I ended up inserting store records on combobox.render:

{
    xtype: 'combo',
    displayField: 'name',
    valueField: 'value',
    store: {
        type: 'MyInlineStore',
    },
    listeners: {
        render: function(el){
            el.getStore().insert(0, [{name: '[Any]', value: ''}]);
            el.setValue(''); //select [Any] by default
        }
    },
}

Answer 4

Since your adding the combobox values later, why not just initialize the store with one blank value:

store : new Ext.data.JsonStore({
    fields : ['id', 'fullName'],
    data : [{id: 0, fullName: ''}]
}),

Later when you do store.add(theRestOfThem), that blank one will still be there.

Had to revisit this today (15 Apr 2017) for ExtJS 4.2:

The easiest way is to include an empty string in the store as above, it can also be done with a load listener on the store:

listeners: 
{
    load: function(store, records) 
    {
        store.insert(0, [{
            fullName: '',
            id: null
        }]);
    }
}

Then add a tpl config to the combobox with   after the display field:

tpl: '<tpl for="."><div class="x-boundlist-item">{fullName}&nbsp;</div></tpl>',

(the display field is fullName in the OPs case)

Answer 5

In Ext 4.2.1 (probably others), just add to combobox config:

tpl : '<tpl for="."><div class="x-boundlist-item">{fullName}&nbsp;</div></tpl>'

Answer 6

You can add an "empty" record at the beginning:

 listeners: {
     load: function(store, records) {
          store.insert(0, [{
              fullName: ' ',
              id: null
          }]);
     }
  }

Answer 7

this.abcCombo = new Ext.form.ComboBox({
    name : 'abcCombo',
    hiddenName : 'abcCombo-id',
    fieldLabel : "My Combobox",
    width : 250,
    editable : false,
    forceSelection : true,
    mode : 'local',
    triggerAction : 'all',
    valueField : 'id',
    displayField : 'fullName',
    store : new Ext.data.JsonStore({
       fields : ['id', 'fullName']
    }),
    tpl : '<tpl for="."><div class="x-combo-list-item">{fullName}&nbsp;</div></tpl>'

    //make sure to add this
    //if not added, empty item height is very small
    listConfig : {
        getInnerTpl: function () {
            return '<table><tr><td height="12">{fullName}</td></tr></table>';
        }
    }

});

on initializing the component, you can do this (on controller):

populateMyComboBox([yourComboBoxComponent], true);

on the populate function:

populateMyComboBox : function(comboBox, insertEmpty) {
    var list;
    if (insertEmpty) {
        list.push({id : 0, fullName : ''});
    }

    var mStore = Ext.create('Ext.data.Store', {
        fields: ['data', 'label'],
        data : list.concat([real_data])
    }),

    comboBox.bindStore(mStore);
}