EnumHelper.cs枚举助手（枚举描述信息多语言支持）C#

　　C#里面经常会用到枚举类型，枚举是值类型对象，如果你想用枚举类型的多属性特性，或者你想在MVC页面上通过简单的值类型转换，将某字段值所代表的含义转换为文字显示，这时候必须要将枚举扩展，是它支持文本描述属性，或者显示名称属性，亦或者多语言支持。例如同一个值类型的字段值，你想让它显示中文描述，英文描述……
请看下面的扩展示例：
  1 using System;
  2 using System.Collections.Generic;
  3 using System.Linq;
  4 using System.Reflection;
  5 using System.Collections.Concurrent;
  6 using System.ComponentModel;
  7 using System.Web.Mvc;
  8 using System.Collections.Specialized;
  9 
 10 namespace ZCPT.CrowdFunding.Web.Extension
 11 {
 12     /// <summary>
 13     /// 枚举助手
 14     /// 熊学浩
 15     /// </summary>
 16     public static class EnumHelper
 17     {
 18         #region Field
 19 
 20         private static ConcurrentDictionary<Type, Dictionary<int, string>> enumDisplayValueDict = new ConcurrentDictionary<Type, Dictionary<int, string>>();
 21         private static ConcurrentDictionary<Type, Dictionary<string, int>> enumValueDisplayDict = new ConcurrentDictionary<Type, Dictionary<string, int>>();
 22         private static ConcurrentDictionary<Type, Dictionary<int, string>> enumNameValueDict = new ConcurrentDictionary<Type, Dictionary<int, string>>();
 23         private static ConcurrentDictionary<Type, Dictionary<string, int>> enumValueNameDict = new ConcurrentDictionary<Type, Dictionary<string, int>>();
 24 
 25         private static ConcurrentDictionary<Type, Dictionary<int, Tuple<string, int>>> enumSeqDisplayValueDict = new ConcurrentDictionary<Type, Dictionary<int, Tuple<string, int>>>();
 26         private static ConcurrentDictionary<string, Type> enumTypeDict = null;
 27 
 28         #endregion
 29 
 30         #region Method
 31         /// <summary>
 32         /// 获取枚举对象Key与显示名称的字典
 33         /// </summary>
 34         /// <param name="enumType"></param>
 35         /// <returns></returns>
 36         public static Dictionary<int, string> GetEnumDictionary(Type enumType)
 37         {
 38             if (!enumType.IsEnum)
 39                 throw new Exception("给定的类型不是枚举类型");
 40 
 41             Dictionary<int, string> names = enumNameValueDict.ContainsKey(enumType) ? enumNameValueDict[enumType] : new Dictionary<int, string>();
 42 
 43             if (names.Count == 0)
 44             {
 45                 names = GetEnumDictionaryItems(enumType);
 46                 enumNameValueDict[enumType] = names;
 47             }
 48             return names;
 49         }
 50 
 51         private static Dictionary<int, string> GetEnumDictionaryItems(Type enumType)
 52         {
 53             FieldInfo[] enumItems = enumType.GetFields(BindingFlags.Public | BindingFlags.Static);
 54             Dictionary<int, string> names = new Dictionary<int, string>(enumItems.Length);
 55 
 56             foreach (FieldInfo enumItem in enumItems)
 57             {
 58                 int intValue = (int)enumItem.GetValue(enumType);
 59                 names[intValue] = enumItem.Name;
 60             }
 61             return names;
 62         }
 63 
 64         /// <summary>
 65         /// 获取枚举对象显示名称与Key的字典
 66         /// </summary>
 67         /// <param name="enumType"></param>
 68         /// <returns></returns>
 69         public static Dictionary<string, int> GetEnumValueNameItems(Type enumType)
 70         {
 71             if (!enumType.IsEnum)
 72                 throw new Exception("给定的类型不是枚举类型");
 73 
 74             Dictionary<string, int> values = enumValueNameDict.ContainsKey(enumType) ? enumValueNameDict[enumType] : new Dictionary<string, int>();
 75 
 76             if (values.Count == 0)
 77             {
 78                 values = TryToGetEnumValueNameItems(enumType);
 79                 enumValueNameDict[enumType] = values;
 80             }
 81             return values;
 82         }
 83 
 84         private static Dictionary<string, int> TryToGetEnumValueNameItems(Type enumType)
 85         {
 86             FieldInfo[] enumItems = enumType.GetFields(BindingFlags.Public | BindingFlags.Static);
 87             Dictionary<string, int> values = new Dictionary<string, int>(enumItems.Length);
 88 
 89             foreach (FieldInfo enumItem in enumItems)
 90             {
 91                 int intValue = (int)enumItem.GetValue(enumType);
 92                 values[enumItem.Name] = intValue;
 93             }
 94             return values;
 95         }
 96 
 97 
 98         /// <summary>
 99         /// 获取枚举对象的值内容
100         /// </summary>
101         /// <param name="enumType"></param>
102         /// <param name="display"></param>
103         /// <returns></returns>
104         public static int TryToGetEnumValueByName(this Type enumType, string name)
105         {
106             if (!enumType.IsEnum)
107                 throw new Exception("给定的类型不是枚举类型");
108             Dictionary<string, int> enumDict = GetEnumValueNameItems(enumType);
109             return enumDict.ContainsKey(name) ? enumDict[name] : enumDict.Select(d => d.Value).FirstOrDefault();
110         }
111 
112         /// <summary>
113         /// 获取枚举类型
114         /// </summary>
115         /// <param name="assembly"></param>
116         /// <param name="typeName"></param>
117         /// <returns></returns>
118         public static Type TrytoGetEnumType(Assembly assembly, string typeName)
119         {
120             enumTypeDict = enumTypeDict ?? LoadEnumTypeDict(assembly);
121             if (enumTypeDict.ContainsKey(typeName))
122             {
123                 return enumTypeDict[typeName];
124             }
125             return null;
126         }
127 
128         private static ConcurrentDictionary<string, Type> LoadEnumTypeDict(Assembly assembly)
129         {
130             Type[] typeArray = assembly.GetTypes();
131             Dictionary<string, Type> dict = typeArray.Where(o => o.IsEnum).ToDictionary(o => o.Name, o => o);
132             ConcurrentDictionary<string, Type> enumTypeDict = new ConcurrentDictionary<string, Type>(dict);
133             return enumTypeDict;
134         }
135 
136         #endregion
137         /// <summary>
138         /// 枚举显示名(属性扩展)
139         /// </summary>
140         public class EnumDisplayNameAttribute : Attribute
141         {
142             private string _displayName;
143 
144             public EnumDisplayNameAttribute(string displayName)
145             {
146                 this._displayName = displayName;
147             }
148 
149             public string DisplayName
150             {
151                 get { return _displayName; }
152             }
153         }
154 
155         public class EnumExt
156         {
157             /// <summary>
158             /// 根据枚举成员获取自定义属性EnumDisplayNameAttribute的属性DisplayName
159             /// </summary>
160             /// <param name="o"></param>
161             /// <returns></returns>
162             public static string GetEnumDisplayName(object o)
163             {
164                 //获取枚举的Type类型对象
165                 Type t = o.GetType();
166 
167                 //获取枚举的所有字段
168                 FieldInfo[] ms = t.GetFields();
169 
170                 //遍历所有枚举的所有字段
171                 foreach (FieldInfo f in ms)
172                 {
173                     if (f.Name != o.ToString())
174                     {
175                         continue;
176                     }
177 
178                     //第二个参数true表示查找EnumDisplayNameAttribute的继承链
179                     if (f.IsDefined(typeof(EnumDisplayNameAttribute), true))
180                     {
181                         return
182                             (f.GetCustomAttributes(typeof(EnumDisplayNameAttribute), true)[0] as EnumDisplayNameAttribute)
183                                 .DisplayName;
184                     }
185                 }
186 
187                 //如果没有找到自定义属性，直接返回属性项的名称
188                 return o.ToString();
189             }
190 
191             /// <summary>
192             /// 根据枚举转换成SelectList
193             /// </summary>
194             /// <param name="enumType">枚举</param>
195             /// <returns></returns>
196             public static List<SelectListItem> GetSelectList(Type enumType)
197             {
198                 List<SelectListItem> selectList = new List<SelectListItem>();
199                 foreach (object e in Enum.GetValues(enumType))
200                 {
201                     selectList.Add(new SelectListItem() { Text = GetDescription(e), Value = ((int)e).ToString() });
202                 }
203                 return selectList;
204             }
205         }
206 
207         /// <summary>
208         /// 根据枚举转换成SelectList并且设置默认选中项
209         /// </summary>
210         /// <param name="enumType"></param>
211         /// <param name="ObjDefaultValue">默认选中项</param>
212         /// <returns></returns>
213         public static List<SelectListItem> GetSelectList(Type enumType, object ObjDefaultValue)
214         {
215             int defaultValue = Int32.Parse(ObjDefaultValue.ToString());
216             List<SelectListItem> selectList = new List<SelectListItem>();
217             foreach (object e in Enum.GetValues(enumType))
218             {
219                 try
220                 {
221                     if ((int)e == defaultValue)
222                     {
223                         selectList.Add(new SelectListItem() { Text = GetDescription(e), Value = ((int)e).ToString(), Selected = true });
224                     }
225                     else
226                     {
227                         selectList.Add(new SelectListItem() { Text = GetDescription(e), Value = ((int)e).ToString() });
228                     }
229                 }
230                 catch (Exception ex)
231                 {
232                     string exs = ex.Message;
233                 }
234             }
235             return selectList;
236         }
237 
238         /// <summary>
239         /// 根据枚举转换成SelectList
240         /// </summary>
241         /// <param name="enumType">枚举</param>
242         /// <returns></returns>
243         public static List<SelectListItem> GetSelectList(Type enumType)
244         {
245             List<SelectListItem> selectList = new List<SelectListItem>();
246             foreach (object e in Enum.GetValues(enumType))
247             {
248                 selectList.Add(new SelectListItem() { Text = GetDescription(e), Value = ((int)e).ToString() });
249             }
250             return selectList;
251         }
252         /// <summary>
253         /// 根据枚举成员获取自定义属性EnumDisplayNameAttribute的属性DisplayName
254         /// </summary>
255         /// <param name="objEnumType"></param>
256         /// <returns></returns>
257         public static Dictionary<string, int> GetDescriptionAndValue(Type enumType)
258         {
259             Dictionary<string, int> dicResult = new Dictionary<string, int>();
260 
261             foreach (object e in Enum.GetValues(enumType))
262             {
263                 dicResult.Add(GetDescription(e), (int)e);
264             }
265 
266             return dicResult;
267         }
268 
269         /// <summary>
270         /// 根据枚举成员获取DescriptionAttribute的属性Description
271         /// </summary>
272         /// <param name="o"></param>
273         /// <returns></returns>
274         public static string GetDescription(object o)
275         {
276             //获取枚举的Type类型对象
277             Type t = o.GetType();
278 
279             //获取枚举的所有字段
280             FieldInfo[] ms = t.GetFields();
281 
282             //遍历所有枚举的所有字段
283             foreach (FieldInfo f in ms)
284             {
285                 if (f.Name != o.ToString())
286                 {
287                     continue;
288                 }
289                 ////  Description
290                 //  //第二个参数true表示查找EnumDisplayNameAttribute的继承链
291                 //  if (f.IsDefined(typeof(EnumDisplayNameAttribute), true))
292                 //  {
293                 //      return
294                 //        (f.GetCustomAttributes(typeof(EnumDisplayNameAttribute), true)[0] as EnumDisplayNameAttribute)
295                 //          .DisplayName;
296                 //  } 
297                 FieldInfo fi = o.GetType().GetField(o.ToString());
298                 try
299                 {
300                     var attributes = (DescriptionAttribute[])fi.GetCustomAttributes(typeof(DescriptionAttribute), false);
301                     return (attributes != null && attributes.Length > 0) ? attributes[0].Description : o.ToString();
302                 }
303                 catch
304                 {
305                     return "(Unknow)";
306                 }
307             }
308 
309             //如果没有找到自定义属性，直接返回属性项的名称
310             return o.ToString();
311         }
312 
313         #region 新增扩展方法
314 
315         /// <summary>  
316         /// 扩展方法：根据枚举值得到相应的枚举定义字符串  
317         /// </summary>  
318         /// <param name="value"></param>  
319         /// <param name="enumType"></param>  
320         /// <returns></returns>  
321         public static String ToEnumString(this int value, Type enumType)
322         {
323             NameValueCollection nvc = GetEnumStringFromEnumValue(enumType);
324             return nvc[value.ToString()];
325         }
326 
327         /// <summary>  
328         /// 根据枚举类型得到其所有的 值 与 枚举定义字符串 的集合  
329         /// </summary>  
330         /// <param name="enumType"></param>  
331         /// <returns></returns>  
332         public static NameValueCollection GetEnumStringFromEnumValue(Type enumType)
333         {
334             NameValueCollection nvc = new NameValueCollection();
335             Type typeDescription = typeof(DescriptionAttribute);
336             System.Reflection.FieldInfo[] fields = enumType.GetFields();
337             string strText = string.Empty;
338             string strValue = string.Empty;
339             foreach (FieldInfo field in fields)
340             {
341                 if (field.FieldType.IsEnum)
342                 {
343                     strValue = ((int)enumType.InvokeMember(field.Name, BindingFlags.GetField, null, null, null)).ToString();
344                     nvc.Add(strValue, field.Name);
345                 }
346             }
347             return nvc;
348         }
349 
350         /// <summary>  
351         /// 扩展方法：根据枚举值得到属性Description中的描述, 如果没有定义此属性则返回空串  
352         /// </summary>  
353         /// <param name="value"></param>  
354         /// <param name="enumType"></param>  
355         /// <returns></returns>  
356         public static String ToEnumDescriptionString(this int value, Type enumType)
357         {
358             NameValueCollection nvc = GetNVCFromEnumValue(enumType);
359             return nvc[value.ToString()];
360         }
361 
362         /// <summary>  
363         /// 根据枚举类型得到其所有的 值 与 枚举定义Description属性 的集合  
364         /// </summary>  
365         /// <param name="enumType"></param>  
366         /// <returns></returns>  
367         public static NameValueCollection GetNVCFromEnumValue(Type enumType)
368         {
369             NameValueCollection nvc = new NameValueCollection();
370             Type typeDescription = typeof(DescriptionAttribute);
371             System.Reflection.FieldInfo[] fields = enumType.GetFields();
372             string strText = string.Empty;
373             string strValue = string.Empty;
374             foreach (FieldInfo field in fields)
375             {
376                 if (field.FieldType.IsEnum)
377                 {
378                     strValue = ((int)enumType.InvokeMember(field.Name, BindingFlags.GetField, null, null, null)).ToString();
379                     object[] arr = field.GetCustomAttributes(typeDescription, true);
380                     if (arr.Length > 0)
381                     {
382                         DescriptionAttribute aa = (DescriptionAttribute)arr[0];
383                         strText = aa.Description;
384                     }
385                     else
386                     {
387                         strText = "";
388                     }
389                     nvc.Add(strValue, strText);
390                 }
391             }
392             return nvc;
393         }
394 
395         #endregion
396     }
397 }