将多个下拉列表选择组合为1个变量

Question

我的订单有10个下拉列表，用户可以在其中选择项目。我想将所有选定的项目组合成一个用逗号分隔的变量。我这样做的方法是为每个单独的下拉列表使用if语句并添加到字符串，这是最有效的方法吗？这是我的语法的子集（不是所有10个下拉列表），但你会明白这一点：

string fullselection = null;

if (dropdownlist1.SelectedIndex > -1) { fullselection += dropdownlist1.SelectedItem.Text; }
if (dropdownlist2.SelectedIndex > -1) { fullselection += "," + dropdownlist2.SelectedItem.Text; }
if (dropdownlist3.SelectedIndex > -1) { fullselection += "," + dropdownlist3.SelectedItem.Text; }
if (dropdownlist4.SelectedIndex > -1) { fullselection += "," + dropdownlist4.SelectedItem.Text; }
if (dropdownlist5.SelectedIndex > -1) { fullselection += "," + dropdownlist5.SelectedItem.Text; }
if (dropdownlist6.SelectedIndex > -1) { fullselection += "," + dropdownlist6.SelectedItem.Text; }

Answer 1

这样的事情应该有效..

var ddlist = new List<DropdownList>();
ddlist.Add(dropdownlist1);//repeat this for all drowdowns.
var selectedTexts = ddlist.Where(x=>x.SelectedIndex > -1).Select(y=>y.SelectedItem.Text);
var fullselection = String.Join(",",selectedTexts.ToArray());