Question

我有一个名为Program的模型。每个节目都将有如下所述的电视节目表。

enum SchduleEnum { Daily = 0, Weekly, Monthly };

每个节目都可以有“新闻”，“电影”，“讨论”等类别。

在“计划安排”视图中，用户必须能够从下拉列表中选择计划。但是，计划下拉列表中应该有默认值。规则是默认时间表应为“每日”，如果它是“新闻”类别。如果类别为“电影”，则默认计划应为“每周”。如果类别为“讨论”，则默认计划应为“每月”。

我有以下代码，在计划下拉列表中显示空白作为默认值。我们如何根据上面定义的规则修改代码以显示所需的默认值？

基于MVC原则：The UI logic belongs in the view. Input logic belongs in the controller. Business logic belongs in the model.

我们如何快速实现？
我们如何达到标准方式（遵循上面列出的MVC原则）

CODE

public class Program
{
    public int ProgramID { get; set; }
    public string ProgramName { get; set; }
    public int ScheduleID { get; set; }
    public string ProgramCategory { get; set; }
}

CONTROLLER

namespace MyDefaultValueTEST.Controllers
{
public class MyProgramController : Controller
{
    enum SchduleEnum { Daily = 0, Weekly, Monthly };
    List<Program> programList = new List<Program>()
                          {
                            new Program
                            {
                                ProgramID = 1,ProgramName = "Program1",
                                ProgramCategory = "News"
                            },
                            new Program
                            {
                                ProgramID = 2,ProgramName = "Program2",
                                ProgramCategory = "Movie"
                            },
                            new Program
                            {
                                ProgramID = 3,ProgramName = "Program3",
                                ProgramCategory = "Discussion"
                            }

                          };



    public ActionResult ScheduleProgram()
    {
        ViewBag.ScheudleEnum = GetSchduleSelectList();
        return View(programList);
    }

    public static SelectList GetSchduleSelectList()
    {
        Array values = Enum.GetValues(typeof(SchduleEnum));
        List<System.Web.UI.WebControls.ListItem> items = new List<System.Web.UI.WebControls.ListItem>(values.Length);

        foreach (var i in values)
        {
            items.Add(new System.Web.UI.WebControls.ListItem
                    {
                        Text = Enum.GetName(typeof(SchduleEnum), i),
                        Value = ((int)i).ToString()
                    }
                    );
        }

        return new SelectList(items);
    }


    }
}

查看

@model IEnumerable<MyDefaultValueTEST.Program>

@{
ViewBag.Title = "ScheduleProgram";
}

<h2>ScheduleProgram</h2>


@using (Html.BeginForm())
{
<table>
    <tr>
        <th style="border:1px solid Teal; background-color:Gray">
            ProgramName
        </th>
        <th style="border:1px solid Teal; background-color:Gray">
            ProgramCategory
        </th>
        <th style="border:1px solid Teal; background-color:Gray">  </th>
    </tr>

    @Html.EditorForModel()

</table>

<p>
    <input type="submit" value="Save Schedules" />
</p>
}

EDITOR TEMPLATE（Program.cshtml）

@model MyDefaultValueTEST.Program
<tr>
<td style="border:1px solid Teal">
    @Html.EditorFor(x => x.ProgramName)
</td>
<td style="border:1px solid Teal">
    @Html.EditorFor(x => x.ProgramCategory)
</td>
<td style="border:1px solid Teal">
    @Html.DropDownListFor(x => x.ScheduleID, (SelectList)ViewBag.ScheudleEnum, String.Empty)
</td>
<td>
    @Html.HiddenFor(x => x.ProgramID)
</td>

</tr>

阅读

Answer 1

您可以将模型声明为

public class TestModel
{
    public SchduleEnum SelectedScheduleEnum { get; set; }
    public ProgramCatagory SelectedProgram { get; set; }

    public IEnumerable<SelectListItem> ScheduleEnums
    {
        get { return this.GetScheduleEnums(); }
    }

    public IEnumerable<SelectListItem> SelectedPrograms
    {
        get { return this.GetSelectedPrograms(); }
    }

    private IEnumerable<SelectListItem> GetSelectedPrograms()
    {
        List<SelectListItem> items=new List<SelectListItem>();
        Enum.GetNames(typeof(ProgramCatagory)).ToList().ForEach(s=>{
            bool IsSelected=((int)Enum.Parse(typeof(ProgramCatagory), s)).Equals((int)SelectedScheduleEnum);
            if(IsSelected)
                this.SelectedProgram = (ProgramCatagory)Enum.Parse(typeof(ProgramCatagory), s);
            items.Add(new SelectListItem()
                {
                    Text = s,
                    Value = s,
                    Selected = IsSelected
                });
        });
        return items;
    }

    private IEnumerable<SelectListItem> GetScheduleEnums()
    {
        List<SelectListItem> items = new List<SelectListItem>();
        Enum.GetNames(typeof(SchduleEnum)).ToList().ForEach(s =>
        {
            bool IsSelected = ((int)Enum.Parse(typeof(SchduleEnum),s)).Equals((int)SelectedProgram);
            if (IsSelected)
                this.SelectedScheduleEnum = (SchduleEnum)Enum.Parse(typeof(SchduleEnum), s);
            items.Add(new SelectListItem()
            {
                Text = s,
                Value = s,
                Selected = IsSelected
            });
        });
        return items;
    }

}
public enum SchduleEnum {
    Daily = 0, 
    Weekly,
    Monthly 
};
public enum ProgramCatagory
{
    News=0 ,
    Movie,
    Discussion
};

在控制器中，

public ActionResult Index()
    {

        TestModel model = new TestModel();
        model.SelectedScheduleEnum = SchduleEnum.Monthly;
        return View(model);
    }

在视图中，您可以调用，

<%:Html.DropDownListFor(m=>m.SelectedProgram,Model.SelectedPrograms)%>
<%:Html.DropDownListFor(m=>m.SelectedScheduleEnum,Model.ScheduleEnums) %>

ASP.NET MVC3：Dropdown中的默认值选择

1 个答案: