Ext.override(Ext.form.DisplayField, {
  getValue: function () {
    return this.value;
  },
  setValue: function (v) {
    this.value = v;
    this.setRawValue(this.formatValue(v));
    return this;
  },
  formatValue: function (v) {
    if (this.dateFormat && Ext.isDate(v)) {
      return v.dateFormat(this.dateFormat);
    }
    if (this.numberFormat && typeof v == 'number') {
      return Ext.util.Format.number(v, this.numberFormat);
    }
    return v;
  }
});