Razor视图中DropDownList数据绑定的简化

1 @Html.ComboxListFor(m => m.Month,new []{1,2,3,4,5,6,7,8,9,10,11,12}, "--月--", new { @class = "someStyle" })

1 @Html.ComboxEnumListFor(m => m.IDType, typeof(IDType), "--请选择证件类型--")

1 @Html.ComboxListFor(x => x.YourCity, CityBLL.GetList(), "CityName", "CityID", "--请选择城市--", new { @class = "someStyle" })

1 using System.Collections.Generic;
  2 using System.Linq;
  3 using System.Linq.Expressions;
  4 using System.Web.Mvc.Html;
  5
  6 namespace System.Web.Mvc
  7 {
  8     /// <summary>
  9     /// Extended the HtmlHelper for DropDownList
10     /// </summary>
11     public  static class ComboxExtensions
12     {
13
14         #region 简单类型下拉框
15
16         public static MvcHtmlString ComboxListFor<TModel, TProperty, TPropertyType>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression, IEnumerable<TPropertyType> values)
17         {
18             return ComboxListFor(htmlHelper, expression, values, new object());
19         }
20
21         public static MvcHtmlString ComboxListFor<TModel, TProperty, TPropertyType>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression, IEnumerable<TPropertyType> values, object htmlAttributes)
22         {
23             return ComboxListFor(htmlHelper, expression, values, null, new object());
24         }
25
26         public static MvcHtmlString ComboxListFor<TModel, TProperty, TPropertyType>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression, IEnumerable<TPropertyType> values, string optionLabel)
27         {
28             return ComboxListFor(htmlHelper, expression, values, optionLabel, new object());
29         }
30
31         public static MvcHtmlString ComboxListFor<TModel, TProperty, TPropertyType>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression, IEnumerable<TPropertyType> values, string optionLabel, object htmlAttributes)
32         {
33             return ComboxListForIt(htmlHelper, expression, values, null, null, optionLabel, htmlAttributes);
34         }
35
36         #endregion
37
38         #region 枚举下拉框
39
40         public static MvcHtmlString ComboxEnumListFor<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression, Type enumType)
41         {
42             return ComboxEnumListFor(htmlHelper, expression, enumType, new object());
43         }
44
45         public static MvcHtmlString ComboxEnumListFor<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression, Type enumType, object htmlAttributes)
46         {
47             return ComboxEnumListFor(htmlHelper, expression, enumType, null, new object());
48         }
49
50         public static MvcHtmlString ComboxEnumListFor<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression, Type enumType, string optionLabel)
51         {
52             return ComboxEnumListFor(htmlHelper, expression, enumType, optionLabel, new object());
53         }
54
55         public static MvcHtmlString ComboxEnumListFor<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression, Type enumType, string optionLabel, object htmlAttributes)
56         {
57             if (!enumType.IsEnum)
58             {
59                 throw new ArgumentException("参数必须为枚举类型");
60             }
61
62             var enumItems1 = (from Enum e in Enum.GetValues(enumType)
63                              select new KeyValuePair<Enum,string>(e,EnumUtils.GetDescription(e))
64                              ).ToList();
65
66             return ComboxListForIt(htmlHelper, expression, enumItems1, "Key", "Value", optionLabel, htmlAttributes);
67         }
68
69         #endregion
70
71         #region 稍特殊类型下拉框，ViewModel属性对应的待选项是个另外一个对象的属性集合
72
73         public static MvcHtmlString ComboxListFor<TModel, TProperty, TPropertyType>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression, IEnumerable<TPropertyType> values, string dataValueField, string dataTextField)
74         {
75             return ComboxListFor(htmlHelper, expression, values,dataValueField, dataTextField, new object());
76         }
77
78         public static MvcHtmlString ComboxListFor<TModel, TProperty, TPropertyType>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression, IEnumerable<TPropertyType> values,string dataValueField, string dataTextField, object htmlAttributes)
79         {
80             return ComboxListFor(htmlHelper, expression, values,dataValueField, dataTextField, null, new object());
81         }
82
83         public static MvcHtmlString ComboxListFor<TModel, TProperty, TPropertyType>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression, IEnumerable<TPropertyType> values,string dataValueField, string dataTextField, string optionLabel)
84         {
85             return ComboxListFor(htmlHelper, expression, values, dataValueField, dataTextField, optionLabel, new object());
86         }
87
88         public static MvcHtmlString ComboxListFor<TModel, TProperty,TPropertyType>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression, IEnumerable<TPropertyType> values, string dataValueField, string dataTextField, string optionLabel, object htmlAttributes)
89         {
90             return ComboxListForIt(htmlHelper, expression, values, dataValueField, dataTextField, optionLabel, htmlAttributes);
91         }
92
93         #endregion
94
95         #region base，其实只有这个
96
97         private static MvcHtmlString ComboxListForIt<TModel, TProperty, TPropertyType>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression, IEnumerable<TPropertyType> values, string dataValueField, string dataTextField, string optionLabel, object htmlAttributes)
98         {
99             Type tPropertyType = typeof(TPropertyType);
100
101             var modelMetadata = ModelMetadata.FromLambdaExpression(expression, htmlHelper.ViewData);
102             var selectValue = new object();
103
104             if (modelMetadata.Model != null)
105             {
106                 selectValue = modelMetadata.Model;
107             }
108
109             SelectList selectList;
110
111             if (tPropertyType == typeof(int)
112                 || tPropertyType == typeof(uint)
113                 || tPropertyType == typeof(long)
114                 || tPropertyType == typeof(ulong)
115                 || tPropertyType == typeof(long)
116                 || tPropertyType == typeof(ulong)
117                 || tPropertyType == typeof(short)
118                 || tPropertyType == typeof(ushort)
119                 || tPropertyType == typeof(byte)
120                 || tPropertyType == typeof(sbyte)
121                 || tPropertyType == typeof(decimal)
122                 )
123             {
124                 var values1 = values.Select(x => new CBItem(x));
125                 selectList = new SelectList(values1, "Value","Text",selectValue);
126             }
127             else
128             {
129
130                 if (tPropertyType.IsPrimitive || tPropertyType == typeof (string))
131                 {
132                     selectList = new SelectList(values, selectValue);
133                 }
134                 else
135                 {
136                     if (dataTextField != null && dataValueField != null)
137                     {
138                         selectList = new SelectList(values, dataValueField, dataTextField, selectValue);
139                     }
140                     else
141                     {
142                         selectList = new SelectList(values, selectValue);
143                     }
144                 }
145
146             }
147
148             return htmlAttributes == null
149                        ? (optionLabel == null
150                               ? htmlHelper.DropDownListFor(expression, selectList)
151                               : htmlHelper.DropDownListFor(expression, selectList, optionLabel))
152                        : (optionLabel == null
153                               ? htmlHelper.DropDownListFor(expression, selectList, htmlAttributes)
154                               : htmlHelper.DropDownListFor(expression, selectList, optionLabel, htmlAttributes));
155         }
156
157         /// <summary>
158         /// 一个辅助的待选项类
159         /// </summary>
160          public class CBItem
161         {
162
163             private string _text = String.Empty;
164             private object _value = default(object);
165
166             public CBItem()
167             { }
168
169             public CBItem(object value, string text)
170             {
171                 _text = text;
172                 _value = value;
173             }
174
175             public CBItem(object value)
176             {
177                 _text = value.ToString();
178                 _value = value;
179             }
180
181             /// <summary>
182             /// Text
183             /// </summary>
184             public string Text
185             {
186                 get { return _text; }
187                 set { _text = value; }
188             }
189
190             /// <summary>
191             /// Value
192             /// </summary>
193             public object Value
194             {
195                 get { return _value; }
196                 set { _value = value; }
197             }
198
199         }
200
201         #endregion
202
203     }
204 }

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