Currently, no that will not work. DateField should probably have a setter function to allow you to do this as the calendar must be re-rendered in order to reflect the new disabled dates, and simply changing the config property won't do that.
Here's a workaround I whipped up for now:
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
<title>Test Page</title>
<script type="text/javascript" src="../_src/1.1/adapter/ext/ext-base.js"></script>
<script type="text/javascript" src="../_src/1.1/ext-all-debug.js"></script>
<link rel="stylesheet" type="text/css" href="../_src/1.0/resources/css/ext-all.css">
<script>
Ext.onReady(function(){
Ext.override(Ext.form.DateField, {
setDisabledDates: function(dd){
var re = "(?:";
for(var i = 0; i < dd.length; i++){
re += dd[i];
if(i != dd.length-1) re += "|";
}
this.ddMatch = new RegExp(re + ")");
this.menu.picker.update(this.menu.picker.activeDate.add('mo',-1));
}
});
var df = new Ext.form.DateField({
fieldLabel: 'Arrival',
name: 'arrival',
format: 'd/m/y',
width:190,
allowBlank:false,
disabledDates : ['07/07/07','03/07/07' ],
disabledDatesText: "This date is allready full booked",
renderTo: 'dt'
});
Ext.fly('disableBtn').on('click', function(){
df.setDisabledDates(['10/07/07','11/07/07', '13/07/07']);
})
});
</script>
</head>
<body>
<div id="dt"></div>
<br />
<input id="disableBtn" type="button" value="Change disabled dates" />
</body>
</html>
This adds a new method setDisabledDates to the DateField which takes an array of dates as expected. This is a pretty ugly hack for two reasons. First, the regex logic is duplicated directly from the constructor of DateField, but since it's inline in the constructor currently, there's no way to reuse it. Ideally, the constructor would call this function instead. Secondly, that last line in the override probably looks a little strange. You have to tell the picker to update itself, but it currently has logic that if you're already on the current date, it exits without actually updating. This tells it to change months, forcing it to re-render internally.
So this should work for you for now, but we'll see about making a few changes to DateField so that it supports this correctly.