// Date range filtering in the Filter Row: 
// http://www.devexpress.com/Support/Center/p/E1990.aspx

function ApplyDateRangeFilter(jsonObj) {
    // the json object can contain the following properties:
    // grid 
    // columnFieldName
    // dropDownEdit
    // dateFrom 
    // dateTo
    var d1 = jsonObj.dateFrom.GetText();
    var d2 = jsonObj.dateTo.GetText();
    var currDateRange = jsonObj.dropDownEdit.GetText();
    var newDateRange = d1 + " - " + d2;

    if ((d1 == "") || (d2 == "") || (currDateRange == newDateRange))
        return;

    jsonObj.dropDownEdit.SetText(newDateRange);
    jsonObj.grid.AutoFilterByColumn(jsonObj.columnFieldName, newDateRange);
}

function OnDateRangeFilterDropDown(jsonObj) {
    var str = jsonObj.dropDownEdit.GetText();
    if (str == "") {
        jsonObj.dateFrom.SetDate(new Date("Jan 1, 2008"));
        jsonObj.dateTo.SetDate(new Date());
        return;
    }
    var d = str.split("-");
    jsonObj.dateFrom.SetText(d[0]);
    jsonObj.dateTo.SetText(d[1]);
}