如何多选 ListBox asp.net

Question

我用 asp.net razor 创建了一个列表框。但我希望能够多选列表框。我该怎么做？

我想使用这样的东西：

[HttpPost]
public ActionResult KenmerkSelectie(List<string> VarFromKenmerk1)
{

}

以下列表框仅发布一个变量：

@using (Html.BeginForm("KenmerkSelectie", "KenmerkSelectie", FormMethod.Post, new { id = "kenmerk1" }))
{
    @Html.ListBox("VarFromKenmerk1", (SelectList)ViewBag.var)
    <input type="submit" value="submit"/>
}

编辑： 我正在尝试以下代码，但出现错误：

@using (Html.BeginForm("KenmerkSelectie", "KenmerkSelectie", FormMethod.Post, new { id = "kenmerk1" }))
{
    @Html.ListBoxFor("VarFromKenmerkTEST",(MultiSelectList)ViewBag.var), new {@style = "width: 252px; height: 300px;"}) 
    <input type="submit" value="submit"/>
}


public ActionResult index()
{
    ViewBag.VarFromKenmerk1 = new List<SelectListItem>();
    ViewBag.VarFromKenmerk1.Add(new SelectListItem
    {
        Value = "House",
        Text = "House"
    });

    ViewBag.VarFromKenmerkTEST = new MultiSelectList(ViewBag.VarFromKenmerk1);
    return View();
}


[HttpPost]
public ActionResult KenmerkSelectie(List<string> VarFromKenmerkTEST){
    foreach(var ken in VarFromKenmerkTEST){
        //selected items
    }
}

Compiler Error Message: CS0411: The type arguments for method 'System.Web.Mvc.Html.SelectExtensions.ListBoxFor(System.Web.Mvc.HtmlHelper, System.Linq.Expressions.Expression>, System.Collections.Generic.IEnumerable)' cannot be inferred from the usage. Try specifying the type arguments explicitly.

Source Error: @Html.ListBoxFor("VarFromKenmerkTEST",(MultiSelectList)ViewBag.var), new {@style = "width: 252px; height: 300px;"})

不知道KenmerkSelectie里的参数好不好

Answer 1

您需要设置 SelectList class 的 Selected 属性以及添加属性 new {Multiple = "multiple"}

@{
    var VarFromKenmerk1= new List<SelectList> { 
        new SelectList{ Text = "Text1", Value = "Value1", Selected = true },
        new SelectList { Text = "Text2", Value = "Value2" },
        new SelectList { Text = "Text3", Value = "Value3", Selected = true }
    };
}

@Html.ListBox("VarFromKenmerk1", VarFromKenmerk1, new {Multiple = "multiple"})

Answer 2

您应该使用 viewModel 将数据传递给您的视图（强类型），然后使用

创建您的列表框

@Html.ListBoxFor(viewmodel => viewmodel.model.property, viewmodel.data )

viewmodel 的数据属性应该是 Multiselectlist

视图模型：

public class viewModel
{
    public MultiSelectList data { get; set; }

    public Model model { get; set; }
}

如何多选 ListBox asp.net

How to multiselect ListBox asp.net

c#

asp.net

asp.net-mvc

listbox