前言
上两节我们讲了文件上传的问题,关于这个上传的问题还未结束,我也在花时间做做分割大文件处理以及显示进度的问题,到时完成的话再发表,为了不耽误学习MVC其他内容的计划,我们今天开始好好讲讲关于MVC中下拉框中绑定枚举的几种方式。
话题引入
一般在下拉框中绑定数据的话,分为几种情况。
(1)下拉框中的数据是写死的,我们直接给出死代码即可。
(2)下拉框中的数据从数据库中读取出来,从而进行显示。
(3)下拉框中直接用枚举显示。
(4)下拉框中一个选择的值改变另外一个下拉框中的值。
关于下拉框中绑定大概就是以上四种方式,接下来我们一一来破解,我们样式利用Bootstrap来表示,顺便也温习温习Bootstrap。
下拉框硬编码【一】
我们在控制器中给出如下数据并利用ViewBag来进行传递
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ViewBag.hard_value = new List<SelectListItem>() {
new SelectListItem(){Value= "0" ,Text= "xpy0928" },
new SelectListItem(){Value= "1" ,Text= "cnblogs" }
};
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在数据中进行如下绑定
@Html.DropDownList("hard-code-dropdownlist", new SelectList(ViewBag.hard_value, "Value", "Text"), new { @class = "btn btn-success dropdown-toggle form-control" })
下面我们来看看效果:
下拉框读取数据库【二】
这个要读取数据库,我们就给出一个类测试就ok,并给出默认选中值,测试类:
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public class BlogCategory
{
public int CategoryId { get ; set ; }
public string CategoryName { get ; set ; }
}
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绑定ViewBag传值:
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//从数据库中读取
var categoryList = new List<BlogCategory>() {
new BlogCategory(){CategoryId=1,CategoryName= "C#" },
new BlogCategory(){CategoryId=2,CategoryName= "Java" },
new BlogCategory(){CategoryId=3,CategoryName= "JavaScript" },
new BlogCategory(){CategoryId=4,CategoryName= "C" }
};
var selectItemList = new List<SelectListItem>() {
new SelectListItem(){Value= "0" ,Text= "全部" ,Selected= true }
};
var selectList = new SelectList(categoryList, "CategoryId" , "CategoryName" );
selectItemList.AddRange(selectList);
ViewBag.database = selectItemList;
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视图稍加修改:
@Html.DropDownList("database-dropdownlist", ViewBag.database as IEnumerable<SelectListItem>, new { @class = "btn btn-success dropdown-toggle form-control" })
看看效果:
中 ViewBag.database 需要进行转换否则出现如下错误:
CS1973: “System.Web.Mvc.HtmlHelper<dynamic>”没有名为“DropDownList”的适用方法,但似乎有一个具有该名称的扩展方法。扩展方法不能进行动态调度。请考虑强制转换动态参数,或调用该扩展方法但不使用扩展方法语法。
下拉框绑定枚举【三】(一)
我们同样给出一个测试类:
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public enum Language
{
Chinese,
English,
Japan,
Spanish,
Urdu
}
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获取枚举值并绑定:
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ViewBag.from_enum = Enum.GetValues( typeof (Language)).Cast<Language>();
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视图给出:
@Html.DropDownList("database-dropdownlist", new SelectList(ViewBag.from_enum), new { @class = "btn btn-success dropdown-toggle form-control" })
继续看看成果:
下拉框绑定枚举【三】(二)
利用扩展方法 @Html.EnumDropDownListFor 来实现。接下来依次给出两个类来进行演示:
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public class StudentModel
{
[Display(Name = "语言" )]
public ProgrammingLanguages Language { get ; set ; }
}
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public enum ProgrammingLanguages
{
[Display(Name = "ASP.NET" )]
ASPNet,
[Display(Name = "C# .NET" )]
CSharp,
[Display(Name = "Java" )]
Java,
[Display(Name = "Objective C" )]
ObjectiveC,
[Display(Name = "Visual Basic .NET" )]
VBNet,
[Display(Name = "Visual DataFlex" )]
VisualDataFlex,
[Display(Name = "Visual Fortran" )]
VisualFortran,
[Display(Name = "Visual FoxPro" )]
VisualFoxPro,
[Display(Name = "Visual J++" )]
VisualJPlus
}
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在视图中进行绑定:
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< div class = "form-group" >
@Html.LabelFor(model => model.Language, htmlAttributes: new { @class = "control-label col-md-2" })
< div class = "col-md-10" >
@Html.EnumDropDownListFor(model => model.Language, htmlAttributes: new { @class = "form-control" })
@Html.ValidationMessageFor(model => model.Language, "", new { @class = "text-danger" })
</ div >
</ div >
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我们看看结果
下拉框选择则另一个下拉框对应改变 【四】
此例最合适的例子莫过于省市选择的案例。我们一起来看看。
(1)所属省、市一级雇员类。
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public class Province
{
public int provinceId { get ; set ; }
public string provinceName { get ; set ; }
public string Abbr { get ; set ; }
}
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public class City
{
public int CityId { get ; set ; }
public string CityName { get ; set ; }
public int provinceId { get ; set ; }
}
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public class Employees
{
[Key]
public int EmployeeId { get ; set ; }
[Required, Display(Name = "雇员名字" )]
public string EmployeeName { get ; set ; }
[Required, Display(Name = "地址" )]
public String Address { get ; set ; }
[Required, Display(Name = "所属省" )]
public int Province { get ; set ; }
[Required, Display(Name = "所在城市" )]
public int City { get ; set ; }
[Display(Name = "地区代码" )]
public String ZipCode { get ; set ; }
[Required, Display(Name = "联系号码" )]
public String Phone { get ; set ; }
}
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(2)初始化数据
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List<Province> provinceList = new List<Province>() {
new Province(){provinceId=1,provinceName= "湖南" ,Abbr= "hunan_province" },
new Province(){provinceId=2,provinceName= "广东" ,Abbr= "guangdong_province" },
new Province(){provinceId=3,provinceName= "吉林" ,Abbr= "jilin_province" },
new Province(){provinceId=4,provinceName= "黑龙江" ,Abbr= "heilongjiang_province" }
};
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以及绑定ViewBag到下拉框和控制器上的方法:
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[HttpGet]
public ActionResult Create()
{
ViewBag.ProvinceList = provinceList;
var model = new Employees();
return View(model);
}
[HttpPost]
public ActionResult Create(Employees model)
{
if (ModelState.IsValid)
{
}
ViewBag.ProvinceList = provinceList;
return View(model);
}
public ActionResult FillCity( int provinceId)
{
var cities = new List<City>() {
new City(){CityId=10,CityName= "岳阳市" ,provinceId=1},
new City(){CityId=10,CityName= "深圳市" ,provinceId=2},
new City(){CityId=10,CityName= "吉林市" ,provinceId=3},
new City(){CityId=10,CityName= "哈尔滨市" ,provinceId=4}
};
cities = cities.Where(s => s.provinceId == provinceId).ToList();
return Json(cities, JsonRequestBehavior.AllowGet);
}
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(3)视图展示
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@ using (Html.BeginForm())
{
@Html.AntiForgeryToken()
<div class = "form-horizontal" >
<h4>注册雇员</h4>
<div class = "form-group" >
@Html.LabelFor(m => m.EmployeeName, new { @ class = "control-label col-md-2" })
<div class = "col-md-10" >
@Html.TextBoxFor(m => m.EmployeeName, new { @ class = "form-control" })
@Html.ValidationMessageFor(m => m.EmployeeName, "" , new { @ class = "text-danger" })
</div>
</div>
<div class = "form-group" >
@Html.LabelFor(m => m.Address, new { @ class = "control-label col-md-2" })
<div class = "col-md-10" >
@Html.TextBoxFor(m => m.Address, new { @ class = "form-control" })
@Html.ValidationMessageFor(m => m.Address, "" , new { @ class = "text-danger" })
</div>
</div>
<div class = "form-group" >
@Html.LabelFor(m => m.Province, new { @ class = "control-label col-md-2" })
<div class = "col-md-10" >
@Html.DropDownListFor(m => m.Province,
new SelectList(ViewBag.ProvinceList, "provinceId" , "provinceName" ),
"选择所在省" ,
new { @ class = "form-control" , @onchange = "FillCity()" })
@Html.ValidationMessageFor(m => m.Province, "" , new { @ class = "text-danger" })
</div>
</div>
<div class = "form-group" >
@Html.LabelFor(m => m.City, new { @ class = "control-label col-md-2" })
<div class = "col-md-10" >
@Html.DropDownListFor(m => m.City,
new SelectList(Enumerable.Empty<SelectListItem>(), "CityId" , "CityName" ),
"选择所在市" ,
new { @ class = "form-control" })
@Html.ValidationMessageFor(m => m.City, "" , new { @ class = "text-danger" })
</div>
</div>
<div class = "form-group" >
@Html.LabelFor(m => m.ZipCode, htmlAttributes: new { @ class = "control-label col-md-2" })
<div class = "col-md-10" >
@Html.TextBoxFor(m => m.ZipCode, new { @ class = "form-control" })
@Html.ValidationMessageFor(m => m.ZipCode, "" , new { @ class = "text-danger" })
</div>
</div>
<div class = "form-group" >
@Html.LabelFor(m => m.Phone, new { @ class = "control-label col-md-2" })
<div class = "col-md-10" >
@Html.TextBoxFor(m => m.Phone, new { @ class = "form-control" })
@Html.ValidationMessageFor(m => m.Phone, "" , new { @ class = "text-danger" })
</div>
</div>
<div class = "form-group" >
<div class = "col-md-offset-2 col-md-10" >
<input type= "submit" value= "Create" class = "btn btn-success" />
<a href= "/Home/Employees" class = "btn btn-warning" >Cancel</a>
</div>
</div>
</div>
}
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(4)根据省下拉框选择到市下拉框脚本
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function FillCity() {
var provinceId = $( '#Province' ).val();
$.ajax({
url: '/Home/FillCity' ,
type: "GET" ,
dataType: "JSON" ,
data: { provinceId: provinceId },
success: function (cities) {
$( "#City" ).html( "" );
$.each(cities, function (i, city) {
$( "#City" ).append(
$( '<option></option>' ).val(city.CityId).html(city.CityName));
});
}
});
}
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我们来看看整个过程:
结语
对于下拉框绑定基本上已全部囊括进去,以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持服务器之家。
原文链接:http://www.cnblogs.com/CreateMyself/p/5424894.html