Asp.net mvc 4 选定值的DropDownList不适用于列表中的属性
在ASP MVC 4中,我无法使用DropDownList for设置DropDownList的默认选定值 当我想要预选的属性在列表中时,它在默认情况下不会像预期的那样被选中 以下是我的代码,简化为重要内容: 型号:Asp.net mvc 4 选定值的DropDownList不适用于列表中的属性,asp.net-mvc-4,model,get,selecteditem,html.dropdownlistfor,Asp.net Mvc 4,Model,Get,Selecteditem,Html.dropdownlistfor,在ASP MVC 4中,我无法使用DropDownList for设置DropDownList的默认选定值 当我想要预选的属性在列表中时,它在默认情况下不会像预期的那样被选中 以下是我的代码,简化为重要内容: 型号: public class Renter { ... public virtual List<RentLine> RentLines { get; set; } ... public Renter() { ...
public class Renter
{
...
public virtual List<RentLine> RentLines { get; set; }
...
public Renter()
{
...
RentLines = new List<RentLine>();
...
}
}
public class RentLine
{
...
public Guid RenterId { get; set; }
public virtual Renter Renter { get; set; }
public Guid GarageId { get; set; }
public virtual Garage Garage { get; set; }
...
public RentLine()
{
//
// Testcase for default value in dropdownlist
//
GarageId = new Guid("e926dcac-05ac-4fc1-92a2-014345e6e11c");
}
}
视图模型:
public class AddRenterViewModel
{
public Renter Renter { get; set; }
public List<SelectListItem> RentableGarageItems { get; set; }
...
public AddRenterViewModel()
{
Renter = new Renter();
Renter.RentLines.Add(new RentLine());
RentableGarageItems = new List<SelectListItem>();
foreach (var garage in Singleton.Instance.Entities.GetRentableGarages().OrderBy(g => g.No))
{
RentableGarageItems.Add(new SelectListItem{Text = garage.No.ToString(), Value = garage.Id.ToString()});
}
}
}
结果如下,未选择任何值:
Garage Nr.
<select id="Renter_RentLines_0__GarageId" name="Renter.RentLines[0].GarageId" data-val-required="Das Feld "GarageId" ist erforderlich." data-val="true">
<option value="225a761d-7d12-4e02-9d72-d54fb6934f05">1</option>
<option value="d28fb4fb-d65b-4674-90d6-a4ab9636be80">2</option>
<option value="e06b520b-e876-4870-b321-dc65f77967a7">3</option>
<option value="56832d98-aa5a-4e1a-af44-2d7e00f2bb3a">4</option>
<option value="551f1fa9-13a5-40ce-b795-50063e605027">5</option>
<option value="bace4b40-92ab-4757-9716-2a2878c2c9e8">6</option>
<option value="f9baf45b-96bf-463e-a234-a1522bfc9b9b">7</option>
<option value="91d1d866-6346-4ab0-b2aa-35b56eeaf2b0">8</option>
<option value="62eb3727-eab2-4180-90cd-7dc59119f44e">9</option>
<option value="59768097-c772-4421-b907-a24397a106f5">10</option>
<option value="270acf6b-e4e3-41c3-86dd-4381a313848a">11</option>
<option value="923269cd-1ead-4346-90ce-6344acda5b1b">12</option>
<option value="981ee61e-408b-4b08-a7d3-26c909f04a9d">13</option>
<option value="f1c5043c-fe41-4a8e-8c58-e88363885de4">14</option>
<option value="e926dcac-05ac-4fc1-92a2-014345e6e11c">15</option>
<option value="5577dc00-7cfa-4bcd-99ad-3f356e4325ae">16</option>
</select>
<input id="Renter_RentLines_0__GarageId" type="text" value="e926dcac-05ac-4fc1-92a2-014345e6e11c" name="Renter.RentLines[0].GarageId">
在SelectedListItem创建中缺少Selected属性。i、 e所选=(garage.Id==2)
var entities=新列表()
{
new Guarage(){No=1,Id=1},
new Guarage(){No=2,Id=2},
新担保(){No=3,Id=3}
};
foreach(实体中的var车库)
{
var s=新的SelectListItem
{
Text=garage.No.ToString(),
Value=garage.Id.ToString(),
所选=(garage.Id==2)
};
可出租车库项目。添加(s);
}
默认情况下,这将在下拉列表中选择2
经过一些研究,我找到了一个解决方案
这项工作:
@Html.DropDownListFor(m => m.Renter.RentLines[0].GarageId,
new SelectList(Model.RentableGarageItems, "Value", "Text", Model.Renter.RentLines[0].GarageId))
内联Stephen Muecke对 不幸的是,在循环中呈现控件时,
@Html.DropDownListFor()
的行为与其他帮助程序略有不同。这以前在CodePlex上被报告为一个问题(不确定这是一个bug还是一个限制)
有两个选项可以解决此问题,以确保根据模型特性选择正确的选项
选项1-使用
编辑器或模板
为集合中的类型创建自定义EditorTemplate
。在/Views/Shared/EditorTemplates/AggregationLevelConfiguration.cshtml
中创建分部文件(注意名称必须与类型名称匹配
@model yoursassembly.AggregationLevelConfiguration
@(m=>m.HelperCodeType,(SelectList)ViewData[“CodeTypeItems”])
..//AggregationLevelConfiguration的其他属性
然后在主视图中,将选择列表
传递给编辑器或模板
作为附加视图数据
@使用(Html.BeginForm())
{
...
@EditorFor(m=>m.Configurations,新的{CodeTypeItems=Model.CodeTypeItems})
...
选项2-在每次迭代中生成一个新的
SelectList
,并设置selectedValue
在此选项中,您的属性CodeTypeItems
应该是IEnumerable
,而不是SelectList
(或者只是将codeTypes
设置为公共属性)。然后在主视图中
@Html.DropDownListFor(m=>m.Configurations[0]。HelperCodeType,新选择列表(Model.CodeTypeItems,“Id”,“Name”,Model.Configurations[0]。HelperCodeType)
旁注:无需使用新的{id=“Configurations[0].HelperCodeType”
-方法已生成id
属性
注意:还要再次检查您是否存在以下问题中所述的其他与列表无关的绑定问题:
Garage Nr.
<select id="Renter_RentLines_0__GarageId" name="Renter.RentLines[0].GarageId" data-val-required="Das Feld "GarageId" ist erforderlich." data-val="true">
<option value="225a761d-7d12-4e02-9d72-d54fb6934f05">1</option>
<option value="d28fb4fb-d65b-4674-90d6-a4ab9636be80">2</option>
<option value="e06b520b-e876-4870-b321-dc65f77967a7">3</option>
<option value="56832d98-aa5a-4e1a-af44-2d7e00f2bb3a">4</option>
<option value="551f1fa9-13a5-40ce-b795-50063e605027">5</option>
<option value="bace4b40-92ab-4757-9716-2a2878c2c9e8">6</option>
<option value="f9baf45b-96bf-463e-a234-a1522bfc9b9b">7</option>
<option value="91d1d866-6346-4ab0-b2aa-35b56eeaf2b0">8</option>
<option value="62eb3727-eab2-4180-90cd-7dc59119f44e">9</option>
<option value="59768097-c772-4421-b907-a24397a106f5">10</option>
<option value="270acf6b-e4e3-41c3-86dd-4381a313848a">11</option>
<option value="923269cd-1ead-4346-90ce-6344acda5b1b">12</option>
<option value="981ee61e-408b-4b08-a7d3-26c909f04a9d">13</option>
<option value="f1c5043c-fe41-4a8e-8c58-e88363885de4">14</option>
<option value="e926dcac-05ac-4fc1-92a2-014345e6e11c">15</option>
<option value="5577dc00-7cfa-4bcd-99ad-3f356e4325ae">16</option>
</select>
<input id="Renter_RentLines_0__GarageId" type="text" value="e926dcac-05ac-4fc1-92a2-014345e6e11c" name="Renter.RentLines[0].GarageId">
public class Renter
{
...
public Salutation Salutation { get; set; }
...
public Renter()
{
...
Salutation = Salutation.Male;
...
}
}
public ActionResult Hinzufuegen()
{
var model = new AddRenterViewModel();
return View(model);
}
public class AddRenterViewModel
{
public Renter Renter { get; set; }
public List<SelectListItem> SalutationItems { get; set; }
...
public AddRenterViewModel()
{
Renter = new Renter();
Renter.RentLines.Add(new RentLine());
SalutationItems = new List<SelectListItem>();
foreach (Salutation salutation in Enum.GetValues(typeof(Salutation)))
{
SalutationItems.Add(new SelectListItem { Text = NameEnum.GetName(salutation), Value = salutation.ToString() });
}
}
}
@Html.DropDownListFor(m => m.Renter.Salutation, Model.SalutationItems)
<select id="Renter_Salutation" name="Renter.Salutation" data-val-required="Das Feld "Salutation" ist erforderlich." data-val="true">
<option value="Company">Firma</option>
<option value="Male" selected="selected">Männlich</option>
<option value="Female">Weiblich</option>
</select>
var entities = new List<Guarage>()
{
new Guarage() {No = 1, Id = 1},
new Guarage() {No = 2, Id = 2},
new Guarage() {No = 3, Id = 3}
};
foreach (var garage in entities)
{
var s = new SelectListItem
{
Text = garage.No.ToString(),
Value = garage.Id.ToString(),
Selected = (garage.Id == 2)
};
RentableGarageItems.Add(s);
}
@Html.DropDownListFor(m => m.Renter.RentLines[0].GarageId,
new SelectList(Model.RentableGarageItems, "Value", "Text", Model.Renter.RentLines[0].GarageId))