Question

我想创建一个下拉列表，其价值将保存到我的数据库中。

目前，我有这个工作代码：

MyApplicationProject1
   myApplicationProject1
   myLibraryProject
   myLibraryProject1
   myLibraryProject2
   myLibraryProject3

MyApplicationProject2
   myApplicationProject2
   myLibraryProject
   myLibraryProject1
   myLibraryProject2
   myLibraryProject3

MyApplicationProject3
   myApplicationProject3
   myLibraryProject
   myLibraryProject1
   myLibraryProject2
   myLibraryProject3

但这不是正确的解决方案（代码很难看 - 我需要从2002年到2015年的几年），我想保存在我的模型中。也许这样的事情（尚未测试）：

@Html.DropDownList("YearSelection",new SelectList(new [] {"2002", "2003","2004"}))

我创建的其他方法，但我不知道如何将其称为正确：

型号：

@Html.DropDownListFor(model=>model.StartYearOfFaculty,new SelectList(new [] {"2002", "2003","2004"}))

控制器 - 员工/创建

 namespace DataAccess{

[MetadataType(typeof(EmployeeMD))]
public partial class Employee{
public List <StartYearFaculty> StartYearOFFaculty { get; set; }
}

public class StartYearFaculty{

public int yearOfStartFaculty { get; set; }
}
}

在我的观点中：

public ActionResult Create()
    {
        Employee emp = new Employee();

        emp.StartYearOFFaculty = new List<StartYearFaculty>();
        emp.StartYearOFFaculty.Add(new StartYearFaculty() { yearOfStartFaculty = 2002 });
        emp.StartYearOFFaculty.Add(new StartYearFaculty() { yearOfStartFaculty = 2003 });
        emp.StartYearOFFaculty.Add(new StartYearFaculty() { yearOfStartFaculty = 2004 });
        emp.StartYearOFFaculty.Add(new StartYearFaculty() { yearOfStartFaculty = 2005 });
        emp.StartYearOFFaculty.Add(new StartYearFaculty() { yearOfStartFaculty = 2006 });
        emp.StartYearOFFaculty.Add(new StartYearFaculty() { yearOfStartFaculty = 2007 });
        emp.StartYearOFFaculty.Add(new StartYearFaculty() { yearOfStartFaculty = 2008 });
        emp.StartYearOFFaculty.Add(new StartYearFaculty() { yearOfStartFaculty = 2009 });
        emp.StartYearOFFaculty.Add(new StartYearFaculty() { yearOfStartFaculty = 2010 });
        emp.StartYearOFFaculty.Add(new StartYearFaculty() { yearOfStartFaculty = 2011 });
        emp.StartYearOFFaculty.Add(new StartYearFaculty() { yearOfStartFaculty = 2012 });
        emp.StartYearOFFaculty.Add(new StartYearFaculty() { yearOfStartFaculty = 2013 });
        emp.StartYearOFFaculty.Add(new StartYearFaculty() { yearOfStartFaculty = 2014 });
        emp.StartYearOFFaculty.Add(new StartYearFaculty() { yearOfStartFaculty = 2015 });
        var a = emp.StartYearOFFaculty;

        ViewBag.StartYearFaculty = emp.StartYearOFFaculty;
       return View();
    }

因此是关于IEnumerable类型的错误：

CS1928：'System.Web.Mvc.HtmlHelper'不包含'DropDownListFor'的定义和最佳扩展方法重载'System.Web.Mvc.Html.SelectExtensions.DropDownListFor（System.Web.Mvc.HtmlHelper， System.Linq.Expressions.Expression＆gt;，System.Collections.Generic.IEnumerable）'有一些无效的参数

Answer 1

首先 - 你真的不应该在你的View上使用你的DAL类。对于DropDownListFor帮助程序，最好使用SelectListItem类进行数据收集。

但是，如果您仍想使用自定义类，则应指定集合中的Text和Value字段，如下所示：

@Html.DropDownListFor(m => m.yearOfStartFaculty 
, new SelectList(Model.StartYearOFFaculty,"yearOfStartFaculty","yearOfStartFaculty"));

请注意，您在视图开头定义的模型必须具有yearOfStartFaculty属性。你现在没有。此属性应为string或int，并代表所选值。

但同样最好创建单独的ViewModel并创建一个字段：

public List <SelectListItem> StartYearOFFaculty { get; set; }

而不是：

public List <StartYearFaculty> StartYearOFFaculty { get; set; }

所以你的ViewModel课程看起来像这样：

public class ViewModel
{
   public List<SelectListItem> StartYearOFFaculty { get; set; }
   public int SelectedYear { get; set; }
}

如果您这样做并将其用作控制器，您将能够轻松完成：

@Html.DropDownListFor(m => m.SelectedYear, Model.StartYearOFFaculty);

DropDownListFor与自定义生成列表

1 个答案: