CRM 2016 级联过滤 类比省市县

以下以省市为例:

    function preFilterLookup() {

    //要进行过滤的lookup按钮加入addPresearch事件    
Xrm.Page.getControl("shi").addPreSearch(function () {

            addLookupFilter();

        });

    }

    function addLookupFilter() {

        var sheng= Xrm.Page.getAttribute("sheng").getValue(); //客户类型

        if (sheng!= null) {

            fetchXml = "<filter type='and'><condition attribute='shi.sheng' operator='eq' value='" + sheng + "' /></filter>";

            Xrm.Page.getControl("shi").addCustomFilter(fetchXml);

        }

    }