ExtJS：如何从重写中调用原始方法？

Question

How do I call the original method from an override method?

I have a combobox from which I am removing one of the values from its store to prevent users from selecting it due to the fact that we are no longer supporting that value in that value. I still want that value to be displayed properly if the combobox receives it, because technically, it's not an invalid value; it's just no longer supported. In order to achieve my goal, I want to override the getDisplayValue() method such that, if the combo box receives the value that is no longer in the store, I want the override method to return the correct string, but if it receives any other value, I want the original method to handle it, like so:

myCombobox = Ext.create("Ext.form.field.ComboBox",
  {
    // <snip><snip>
    getDisplayValue: function()
      {
        if (this.value == 'removedValue')
          {
            return 'Correct Text';
          }
        else
          {
            // What do I do here to call original getDisplayValue() and return its returned value?
          }
      }
  });

Update
Someone posted an answer which said to use this.callParent(arguments); but then they deleted the answer after I left a comment saying that that didn't work. I got the override function to do what I want it to do in the else case by putting in the source code from the overridden function (which I got from Sencha's web site), but I'd rather use a solution that involves somehow actually calling that function instead if that's possible, as its source code could change in a later ExtJS update (eg, for a bug fix), while mine would remain static.

(Note that I changed the code slightly to look at the value instead of the rawValue, since the latter isn't necessarily defined at the time of the getDisplayValue() call.)

Answer 1

Even though the question is answered, here is another better way to solve your problem. This is how ExtJS calls it parent method in some of its internal classes.

Ext.create("Ext.form.field.ComboBox", { 
    getDisplayValue: function() {
        if (this.rawValue == 'removedValue') {
            // your logic
            return;
        }
        return Ext.form.field.ComboBox.prototype.getDisplayValue.call(this);
    }
});

Answer 2

If you use Ext.define, in 4.1 it was callOverridden , and since 4.2 it is callParent .

If you use Ext.create to create a combobox, callParent does not bring you to the combobox's function, but to the function of the base class (triggerfield?), which is not what you want.

What I have used successfully once is something like this:

Ext.create('MyCombo',{
    initComponent:function() {
        var me = this;
        me.callParent(arguments);
        var oldFn = me.getDisplayValue;
        me.getDisplayValue = function() {
            if (this.rawValue == 'removedValue') {
                return 'Correct Text';
            } else {
                oldFn.apply(this, arguments); // What do I do here to call original getDisplayValue() and return its returned value?
            }
        };
    }
});

But it is far cleaner if you use Ext.define to derive your special combobox from the default one and then use callParent .