帮我解释一下这一段,谢谢!
这段代码写在用户控件UCProvince1中
if (Request.Form.GetValues("ctl00$ContentPlaceHolder1$UCProvince1$dlProvince") != null)
this.dlProvince.SelectedValue = Request.Form.GetValues("ctl00$ContentPlaceHolder1$UCProvince1$dlProvince").GetValue(0).ToString().ToUpper();
ContentPlaceHolder1模板页中的,UCProvince1用户控件,dlProvince下拉框
特别是里面的ctl00是什么意思?