自己写的一些数据类型扩展方法，还不是很完善，只是现在用到什么就写了什么而已，以后会慢慢更新

  1 using System;
  2 using System.Collections.Generic;
  3 using System.Linq;
  4 using System.Text;
  5 using System.Xml.Linq;
  6 
  7 namespace Tools
  8 {
  9     /// <summary>
 10     /// Dictionary扩展方法
 11     /// </summary>
 12     public static class DictionaryExtensions
 13     {
 14         #region // Dictionary转XML
 15         /// <summary>
 16         /// 将字典转换成XML格式字符串
 17         /// </summary>
 18         /// <param name="dict">字典</param>
 19         /// <returns>字符串</returns>
 20         private static string GetXml<TKey, TValue>(Dictionary<TKey, TValue> dict)
 21         {
 22             StringBuilder xml = new StringBuilder("<?xml version=\"1.0\" encoding=\"utf-8\" ?><xml>");
 23             foreach (var pair in dict)
 24             {
 25                 xml.AppendFormat("<{0}><![CDATA[{1}]]></{2}>", pair.Key, pair.Value, pair.Key);
 26             }
 27             xml.Append("</xml>");
 28             return xml.ToString();
 29         }
 30 
 31         /// <summary>
 32         /// 将字典转换成XML格式字符串
 33         /// </summary>
 34         /// <param name="dict">字典</param>
 35         /// <returns>字符串</returns>
 36         public static string ToXml<TKey, TValue>(this Dictionary<TKey, TValue> dict)
 37             where TKey : struct
 38             where TValue : struct
 39         {
 40             return GetXml(dict);
 41         }
 42 
 43         /// <summary>
 44         /// 将字典转换成XML格式字符串
 45         /// </summary>
 46         /// <param name="dict">字典</param>
 47         /// <returns>字符串</returns>
 48         public static string ToXml<TKey, TValue>(this Dictionary<string, TValue> dict)
 49             where TValue : struct
 50         {
 51             return GetXml(dict);
 52         }
 53 
 54         /// <summary>
 55         /// 将字典转换成XML格式字符串
 56         /// </summary>
 57         /// <param name="dict">字典</param>
 58         /// <returns>字符串</returns>
 59         public static string ToXml<TKey, TValue>(this Dictionary<TKey, string> dict)
 60             where TKey : struct
 61         {
 62             return GetXml(dict);
 63         }
 64 
 65         /// <summary>
 66         /// 将字典转换成XML格式字符串
 67         /// </summary>
 68         /// <param name="dict">字典</param>
 69         /// <returns>字符串</returns>
 70         public static string ToXml(this Dictionary<string, string> dict)
 71         {
 72             return GetXml(dict);
 73         }
 74         #endregion
 75 
 76         #region // Dictionary转Json
 77         /// <summary>
 78         /// 将字典转换成Json字符串
 79         /// </summary>
 80         /// <typeparam name="TKey"></typeparam>
 81         /// <typeparam name="TValue"></typeparam>
 82         /// <param name="dict">字典</param>
 83         /// <returns>字符串</returns>
 84         private static string GetJson<TKey, TValue>(Dictionary<TKey, TValue> dict)
 85         {
 86             List<string> list = new List<string>(dict.Count);
 87             foreach (var pair in dict)
 88             {
 89                 list.Add(string.Format("\"{0}\":\"{1}\"", pair.Key, pair.Value));
 90             }
 91             return "{" + string.Join(",", list.ToArray()) + "}";
 92         }
 93 
 94         /// <summary>
 95         /// 将字典转换成Json字符串
 96         /// </summary>
 97         /// <typeparam name="TKey"></typeparam>
 98         /// <typeparam name="TValue"></typeparam>
 99         /// <param name="dict">字典</param>
100         /// <returns>字符串</returns>
101         public static string ToJson<TKey, TValue>(this Dictionary<TKey, TValue> dict)
102             where TKey: struct
103             where TValue: struct
104         {
105             return GetJson(dict);
106         }
107 
108         /// <summary>
109         /// 将字典转换成Json字符串
110         /// </summary>
111         /// <typeparam name="TKey"></typeparam>
112         /// <typeparam name="TValue"></typeparam>
113         /// <param name="dict">字典</param>
114         /// <returns>字符串</returns>
115         public static string ToJson<TKey, TValue>(this Dictionary<string, TValue> dict)
116             where TValue : struct
117         {
118             return GetJson(dict);
119         }
120 
121         /// <summary>
122         /// 将字典转换成Json字符串
123         /// </summary>
124         /// <typeparam name="TKey"></typeparam>
125         /// <typeparam name="TValue"></typeparam>
126         /// <param name="dict">字典</param>
127         /// <returns>字符串</returns>
128         public static string ToJson<TKey, TValue>(this Dictionary<TKey, string> dict)
129             where TKey : struct
130         {
131             return GetJson(dict);
132         }
133 
134         /// <summary>
135         /// 将字典转换成Json字符串
136         /// </summary>
137         /// <typeparam name="TKey"></typeparam>
138         /// <typeparam name="TValue"></typeparam>
139         /// <param name="dict">字典</param>
140         /// <returns>字符串</returns>
141         public static string ToJson(this Dictionary<string, string> dict)
142         {
143             return GetJson(dict);
144         }
145         #endregion
146 
147         #region // Dictionary转Url键值对字符串
148         /// <summary>
149         /// 将字典的全部键值对拼接成Url键值对格式
150         /// </summary>
151         /// <typeparam name="TKey"></typeparam>
152         /// <typeparam name="TValue"></typeparam>
153         /// <param name="dict"></param>
154         /// <returns></returns>
155         public static string GetUrlKeyValuePair<TKey, TValue>(Dictionary<TKey, TValue> dict)
156         {
157             List<string> list = new List<string>(dict.Count);
158             foreach (var pair in dict)
159             {
160                 list.Add(string.Format("{0}={1}", pair.Key, pair.Value));
161             }
162             return string.Join("&", list.ToArray());
163         }
164 
165         /// <summary>
166         /// 将字典的全部键值对拼接成Url键值对格式
167         /// </summary>
168         /// <typeparam name="TKey"></typeparam>
169         /// <typeparam name="TValue"></typeparam>
170         /// <param name="dict"></param>
171         /// <returns></returns>
172         public static string ToUrlKeyValuePair<TKey, TValue>(this Dictionary<TKey, TValue> dict)
173             where TKey : struct
174             where TValue : struct
175         {
176             return GetUrlKeyValuePair(dict);
177         }
178 
179         /// <summary>
180         /// 将字典的全部键值对拼接成Url键值对格式
181         /// </summary>
182         /// <typeparam name="TKey"></typeparam>
183         /// <typeparam name="TValue"></typeparam>
184         /// <param name="dict"></param>
185         /// <returns></returns>
186         public static string ToUrlKeyValuePair<TKey, TValue>(this Dictionary<string, TValue> dict)
187             where TValue : struct
188         {
189             return GetUrlKeyValuePair(dict);
190         }
191 
192         /// <summary>
193         /// 将字典的全部键值对拼接成Url键值对格式
194         /// </summary>
195         /// <typeparam name="TKey"></typeparam>
196         /// <typeparam name="TValue"></typeparam>
197         /// <param name="dict"></param>
198         /// <returns></returns>
199         public static string ToUrlKeyValuePair<TKey, TValue>(this Dictionary<TKey, string> dict)
200             where TKey : struct
201         {
202             return GetUrlKeyValuePair(dict);
203         }
204 
205         /// <summary>
206         /// 将字典的全部键值对拼接成Url键值对格式
207         /// </summary>
208         /// <typeparam name="TKey"></typeparam>
209         /// <typeparam name="TValue"></typeparam>
210         /// <param name="dict"></param>
211         /// <returns></returns>
212         public static string ToUrlKeyValuePair(this Dictionary<string, string> dict)
213         {
214             return GetUrlKeyValuePair(dict);
215         }
216         #endregion
217 
218         #region // Dictionaty排序
219 
220         #region // 升序
221         private static Dictionary<TKey, TValue> GetAsc<TKey, TValue>(Dictionary<TKey, TValue> dict)
222         {
223             return dict.OrderBy(e => e.Key).ToDictionary(e => e.Key, e => e.Value);
224         }
225 
226         /// <summary>
227         /// 根据Key按升序排序
228         /// </summary>
229         /// <typeparam name="TKey"></typeparam>
230         /// <typeparam name="TValue"></typeparam>
231         /// <param name="dict"></param>
232         /// <returns></returns>
233         public static Dictionary<TKey, TValue> ToAsc<TKey, TValue>(this Dictionary<TKey, TValue> dict)
234             where TKey : struct
235             where TValue : struct
236         {
237             return GetAsc(dict);
238         }
239 
240         /// <summary>
241         /// 根据Key按升序排序
242         /// </summary>
243         /// <typeparam name="TKey"></typeparam>
244         /// <typeparam name="TValue"></typeparam>
245         /// <param name="dict"></param>
246         /// <returns></returns>
247         public static Dictionary<string, TValue> ToAsc<TKey, TValue>(this Dictionary<string, TValue> dict)
248             where TValue : struct
249         {
250             return GetAsc(dict);
251         }
252 
253         /// <summary>
254         /// 根据Key按升序排序
255         /// </summary>
256         /// <typeparam name="TKey"></typeparam>
257         /// <typeparam name="TValue"></typeparam>
258         /// <param name="dict"></param>
259         /// <returns></returns>
260         public static Dictionary<TKey, string> ToAsc<TKey, TValue>(this Dictionary<TKey, string> dict)
261             where TKey : struct
262         {
263             return GetAsc(dict);
264         }
265 
266         /// <summary>
267         /// 根据Key按升序排序
268         /// </summary>
269         /// <typeparam name="TKey"></typeparam>
270         /// <typeparam name="TValue"></typeparam>
271         /// <param name="dict"></param>
272         /// <returns></returns>
273         public static Dictionary<string, string> ToAsc(this Dictionary<string, string> dict)
274         {
275             return GetAsc(dict);
276         }
277         #endregion
278 
279         #region // 降序
280         private static Dictionary<TKey, TValue> GetDesc<TKey, TValue>(Dictionary<TKey, TValue> dict)
281         {
282             return dict.OrderByDescending(e => e.Key).ToDictionary(e => e.Key, e => e.Value);
283         }
284 
285         /// <summary>
286         /// 根据Key按降序排序
287         /// </summary>
288         /// <typeparam name="TKey"></typeparam>
289         /// <typeparam name="TValue"></typeparam>
290         /// <param name="dict"></param>
291         /// <returns></returns>
292         public static Dictionary<TKey, TValue> ToDesc<TKey, TValue>(this Dictionary<TKey, TValue> dict)
293             where TKey : struct
294             where TValue : struct
295         {
296             return GetDesc(dict);
297         }
298 
299         /// <summary>
300         /// 根据Key按降序排序
301         /// </summary>
302         /// <typeparam name="TKey"></typeparam>
303         /// <typeparam name="TValue"></typeparam>
304         /// <param name="dict"></param>
305         /// <returns></returns>
306         public static Dictionary<string, TValue> ToDesc<TKey, TValue>(this Dictionary<string, TValue> dict)
307             where TValue : struct
308         {
309             return GetDesc(dict);
310         }
311 
312         /// <summary>
313         /// 根据Key按降序排序
314         /// </summary>
315         /// <typeparam name="TKey"></typeparam>
316         /// <typeparam name="TValue"></typeparam>
317         /// <param name="dict"></param>
318         /// <returns></returns>
319         public static Dictionary<TKey, string> ToDesc<TKey, TValue>(this Dictionary<TKey, string> dict)
320             where TKey : struct
321         {
322             return GetDesc(dict);
323         }
324 
325         /// <summary>
326         /// 根据Key按降序排序
327         /// </summary>
328         /// <typeparam name="TKey"></typeparam>
329         /// <typeparam name="TValue"></typeparam>
330         /// <param name="dict"></param>
331         /// <returns></returns>
332         public static Dictionary<string, string> ToDesc(this Dictionary<string, string> dict)
333         {
334             return GetDesc(dict);
335         }
336         #endregion
337 
338         #endregion
339 
340         #region // Dictionary操作
341         /// <summary>
342         /// 尝试将键和值添加到字典中：如果不存在，才添加；存在，不添加也不抛导常
343         /// </summary>
344         public static Dictionary<TKey, TValue> TryAdd<TKey, TValue>(this Dictionary<TKey, TValue> dict, TKey key, TValue value)
345         {
346             if (dict.ContainsKey(key) == false)
347             {
348                 dict.Add(key, value);
349             }
350             return dict;
351         }
352 
353         /// <summary>
354         /// 将键和值添加或替换到字典中：如果不存在，则添加；存在，则替换
355         /// </summary>
356         public static Dictionary<TKey, TValue> AddOrReplace<TKey, TValue>(this Dictionary<TKey, TValue> dict, TKey key, TValue value)
357         {
358             dict[key] = value;
359             return dict;
360         }
361 
362         /// <summary>
363         /// 向字典中批量添加键值对
364         /// </summary>
365         /// <param name="replaceExisted">如果已存在，是否替换</param>
366         public static Dictionary<TKey, TValue> AddRange<TKey, TValue>(this Dictionary<TKey, TValue> dict, IEnumerable<KeyValuePair<TKey, TValue>> values, bool replaceExisted)
367         {
368             foreach (var item in values)
369             {
370                 if (dict.ContainsKey(item.Key) == false || replaceExisted)
371                 {
372                     dict[item.Key] = item.Value;
373                 }
374             }
375             return dict;
376         }
377 
378         /// <summary>
379         /// 获取与指定的键相关联的值，如果没有则返回输入的默认值
380         /// </summary>
381         //public static TValue GetValue<TKey, TValue>(this Dictionary<TKey, TValue> dict, TKey key, TValue defaultValue = default(TValue))  // .Net 3.5不支持此写法
382         public static TValue GetValue<TKey, TValue>(this Dictionary<TKey, TValue> dict, TKey key, TValue defaultValue)
383         {
384             return dict.ContainsKey(key) ? dict[key] : defaultValue;
385         }
386         #endregion
387 
388         #region // Dictionary辅助方法
389         /// <summary>
390         /// 判断字典是否有元素
391         /// </summary>
392         /// <typeparam name="T"></typeparam>
393         /// <param name="list"></param>
394         /// <returns>布尔值，True表示有元素，False表示没有元素</returns>
395         public static bool HasItem<TKey, TValue>(this Dictionary<TKey, TValue> dict)
396         {
397             return dict != null && dict.Count > 0;
398         }
399 
400         /// <summary>
401         /// 判断字典是否为空
402         /// </summary>
403         /// <typeparam name="TKey"></typeparam>
404         /// <typeparam name="TValue"></typeparam>
405         /// <param name="dict"></param>
406         /// <returns></returns>
407         public static bool IsNullOrEmpty<TKey, TValue>(this Dictionary<TKey, TValue> dict)
408         {
409             return dict == null || dict.Count == 0;
410         }
411         #endregion
412     }
413 
414     /// <summary>
415     /// List扩展方法
416     /// </summary>
417     public static class ListExtensions
418     {
419         /// <summary>
420         /// 判断集合是否有元素
421         /// </summary>
422         /// <typeparam name="T"></typeparam>
423         /// <param name="list"></param>
424         /// <returns>布尔值，True表示有元素，False表示没有元素</returns>
425         public static bool HasItem<T>(this List<T> list)
426         {
427             return list != null && list.Count > 0;
428         }
429 
430         /// <summary>
431         /// 判断集合是否为空
432         /// </summary>
433         /// <typeparam name="T"></typeparam>
434         /// <param name="list"></param>
435         /// <returns></returns>
436         public static bool IsNullOrEmpty<T>(this List<T> list)
437         {
438             return list == null || list.Count == 0;
439         }
440     }
441 
442     /// <summary>
443     /// String扩展方法
444     /// </summary>
445     public static class StringExtensions
446     {
447         /// <summary>
448         /// 判断当前字符串是否为null或者为Empty
449         /// </summary>
450         /// <param name="value"></param>
451         /// <returns></returns>
452         public static bool IsNullOrEmpty(this string value)
453         {
454             //return string.IsNullOrEmpty(value);
455 
456             return value == null || value == string.Empty;
457         }
458 
459         /// <summary>
460         /// 判断当前字符串是否为null、Empty或者空白
461         /// </summary>
462         /// <param name="value"></param>
463         /// <returns></returns>
464         public static bool IsNullOrWhiteSpace(this string value)
465         {
466             //if (value != null)
467             //{
468             //    return string.IsNullOrEmpty(value.Trim());
469             //}
470             //return true;
471 
472             return value == null || value == string.Empty || value.Trim() == string.Empty;
473         }
474     }
475 
476     /// <summary>
477     /// XElement扩展方法
478     /// </summary>
479     public static class XElementExtensions
480     {
481         /// <summary>
482         /// 根据节点名称获取节点值，获取失败时返回null
483         /// </summary>
484         /// <param name="doc"></param>
485         /// <param name="nodeName">节点名称</param>
486         /// <returns>节点值</returns>
487         public static string TryGetValue(this XElement doc, string nodeName)
488         {
489             XElement xElement = doc.Element(nodeName);
490             if (xElement != null)
491             {
492                 return xElement.Value;
493             }
494             return null;
495         }
496     }
497 }