下拉选择框　设置内容 获取选中项 设置选中项

设置内容
Html.DropDownList创建下拉框，下拉框名称为"useState"，集合为ViewBag.UseStates，值是DicKey，显示是DicValue

<div>
    使用状态
    @Html.DropDownList("useState", new SelectList(ViewBag.UseStates, "DicKey", "DicValue"))
    @{ 
        var UseState = ViewBag.UseState.ToString();
        if (!string.IsNullOrEmpty(UseState))
        {
            if (UseState.Contains("1"))
            {
                <script>$("#useState").find("option:selected").val(1);</script>
            }
            else if (UseState.Contains("2"))
            {
                <script>$("#useState").find("option:selected").val(2);</script>
            }
            else if (UseState.Contains("3"))
            {
                <script>$("#useState").find("option:selected").val(3);</script>
            }
        }
    }
    <button onclick="GetSelectOne()">获取选择项</button>
</div>

<script>
    function GetSelectOne() {
        var UseState = $("#useState").find("option:selected").val();
        layer.alert(UseState);
    }
</script>

public ActionResult DropDownList()
{
    List<DictionaryModel> dic = new List<DictionaryModel>();
    dic.Add(new DictionaryModel() { PKID = 1, DicKey = "1Using", DicValue = "使用中" });
    dic.Add(new DictionaryModel() { PKID = 2, DicKey = "2", DicValue = "未投入使用" });
    dic.Add(new DictionaryModel() { PKID = 3, DicKey = "3", DicValue = "已废弃" });
    ViewBag.UseStates = dic;
    ViewBag.UseState = 1;
    return View();
}

DictionaryModel

public class DictionaryModel
{
    public int PKID { get; set; }
    public string DicKey { get; set; }
    public string DicValue { get; set; }
}