从会话中选择下拉列表值 [英] Select dropdownlist value from session

问题描述

我的html代码中有下拉列表。我想要的是：如果会话location不为null，则从会话中的下拉列表中选择值。我希望你理解我的问题。我是mvc的新手。不知道多少..谢谢

i have dropdownlist in my html code. what i want is: if session "location" is not null then select value from dropdown as it is in the session. i hope you understand my question. i am new to mvc. dont know much.. Thanks

@if (Session["Location"] == null)
{
                <select class="form-control" id="DeliveryLocation" name="DeliveryLocation">
                    <option value="" selected disabled hidden>Choose Your Location</option>
                    <option value="Aundh">Aundh</option>
                    <option value="Baner">Baner</option>
                    <option value="Balewadi">Balewadi</option>
                    <option value="Pimpri">Pimpri</option>
                    <option value="Nilakh">Nilakh</option>
                    <option value="Wakad">Wakad</option>
                   
                </select>
}
else
{
    // i want code here to select value from dropdown as it is in location session
   <pre> <select class="form-control" id="DeliveryLocation" name="DeliveryLocation">
                    <option value="" selected disabled hidden>Choose Your Location</option>
                    <option value="Aundh">Aundh</option>
                    <option value="Baner">Baner</option>
                    <option value="Balewadi">Balewadi</option>
                    <option value="Pimpri">Pimpri</option>
                    <option value="Nilakh">Nilakh</option>
                    <option value="Wakad">Wakad</option>
                   
                </select>

}



我尝试了什么：



i尝试使用javascript但未完成..

}

What I have tried:

i tried using javascript bt not done..

<script>
    $('#DeliveryLocation').val('Baner').change();
</script>

推荐答案

（'＃DeliveryLocation'）。val（'Baner'）。change（） ;
< / script>

('#DeliveryLocation').val('Baner').change(); </script>

你应该阅读一本关于MVC的书或尝试在线教程（谷歌MVC音乐商店）到了解MVC应该如何工作。



基本上你需要一个包含可能位置和所选位置的视图模型，从中你可以使用帮助器来显示给你的下拉菜单。



型号

You should go through a book on MVC or try on-line tutorials (google "MVC Music Store") to understand how MVC is supposed to work.

Basically you need a view model that contains the possible locations and the selected location, and from that you can use a helper to show the dropdown for you.

Model

public class HomeModel
{
    public string Location { get; set; }
    public SelectList Locations { get; set; }

    public HomeModel()
    {
        List<SelectListItem> items = new List<SelectListItem>();

        // these are hard-coded here but can come from a database or
        // some other location

        items.Add(new SelectListItem { Text = "Aundh", Value = "Aundh" });
        items.Add(new SelectListItem { Text = "Baner", Value = "Baner" });
        items.Add(new SelectListItem { Text = "Balewadi", Value = "Balewadi" });
        items.Add(new SelectListItem { Text = "Pimpri", Value = "Pimpri" });

        this.Locations = new SelectList(items, "Value", "Text");
    }

控制器

Controller

[HttpGet]
public ActionResult Index()
{
    HomeModel model = new HomeModel();

    if (Session["Location"] != null)
    {
        model.Location = (string)Session["Location"];
    }

    return View(model);
}

[HttpPost]
public ActionResult Index(HomeModel model)
{

    string selectedLocation = model.Location;

    // remember selection for later
    // you don't need this code here, I'm just doing it for easier testing

    Session["Location"] = selectedLocation;

    return View(model);
}

查看

View

@model HomeModel

@using (Html.BeginForm())
{
    @Html.DropDownListFor(m => m.Location, Model.Locations)

    <p><input type="submit" value="Submit"/></p>
}

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