前两篇简单谈了一些.net core的优势以及机构设计的一些思路，这一篇开始，我们将从零开始搭建架构，底层我们将采用ef来访问数据库，所以这篇我们将贴一下ef常用操作的基类。
简单介绍下一些类库将要实现的功能：
business：业务实现层
domains：实体（model）
service：接口
data：数据库访问（ef或其他）
easycacheing：开源缓存管理
tools：工具类库
其他的我们用到的时候再说；
接着说ef常用操作基类，我们将基类放在data下，具体目录结构如下：
baseentity：实体基类，基础共有的放在这里面：
1 using system;
2 using system.collections.generic;
3 using system.text;
4
5 namespace data
6 {
7 /// <summary>
8 /// base class for entities
9 /// </summary>
10 ///[serializable]
11 public abstract partial class baseentity
12 {
13 /// <summary>
14 /// gets or sets the entity identifier
15 /// </summary>
16 public string id { get; set; }
17 public virtual nullable<datetime> createtime { get; set; }
18 public virtual string createperson { get; set; }
19 public virtual nullable<datetime> updatetime { get; set; }
20 public virtual string updateperson { get; set; }
21
22 public baseentity()
23 {
24 this.id = getidentifier();
25 this.createtime = datetime.now;
26 this.updatetime = datetime.now;
27 }
28
29 private string getidentifier()
30 {
31 return guid.newguid().tostring();
32 }
33
34 public override bool equals(object obj)
35 {
36 return equals(obj as baseentity);
37 }
38
39 private static bool istransient(baseentity obj)
40 {
41 return obj != null && equals(obj.id, default(string));
42 }
43
44 private type getunproxiedtype()
45 {
46 return gettype();
47 }
48
49 public virtual bool equals(baseentity other)
50 {
51 if (other == null)
52 return false;
53
54 if (referenceequals(this, other))
55 return true;
56
57 if (!istransient(this) &&
58 !istransient(other) &&
59 equals(id, other.id))
60 {
61 var othertype = other.getunproxiedtype();
62 var thistype = getunproxiedtype();
63 return thistype.isassignablefrom(othertype) ||
64 othertype.isassignablefrom(thistype);
65 }
66
67 return false;
68 }
69
70 public static bool operator ==(baseentity x, baseentity y)
71 {
72 return equals(x, y);
73 }
74
75 public static bool operator !=(baseentity x, baseentity y)
76 {
77 return !(x == y);
78 }
79 }
80 }
dbcontextextensions：数据库操作扩展
1 using microsoft.entityframeworkcore;
2 using microsoft.entityframeworkcore.infrastructure;
3 using system;
4 using system.collections.generic;
5 using system.data;
6 using system.data.common;
7 using system.data.sqlclient;
8 using system.reflection;
9 using system.text;
10
11 namespace data
12 {
13 public static class dbcontextextensions
14 {
15 private static void combineparams(ref dbcommand command, params object[] parameters)
16 {
17 if (parameters != null)
18 {
19 foreach (sqlparameter parameter in parameters)
20 {
21 if (!parameter.parametername.contains("@"))
22 parameter.parametername = $"@{parameter.parametername}";
23 command.parameters.add(parameter);
24 }
25 }
26 }
27
28
29 private static dbcommand createcommand(databasefacade facade, string sql, out dbconnection dbconn, params object[] parameters)
30 {
31 dbconnection conn = facade.getdbconnection();
32 dbconn = conn;
33 conn.open();
34 dbcommand cmd = conn.createcommand();
35 if (facade.issqlserver())
36 {
37 cmd.commandtext = sql;
38 combineparams(ref cmd, parameters);
39 }
40 return cmd;
41 }
42
43 public static datatable sqlquery(this databasefacade facade, string sql, params object[] parameters)
44 {
45 dbcommand cmd = createcommand(facade, sql, out dbconnection conn, parameters);
46 dbdatareader reader = cmd.executereader();
47 datatable dt = new datatable();
48 dt.load(reader);
49 reader.close();
50 conn.close();
51 return dt;
52 }
53
54 public static ienumerable<t> sqlquery<t>(this databasefacade facade, string sql, params object[] parameters) where t : class, new()
55 {
56 datatable dt = sqlquery(facade, sql, parameters);
57 return dt.toenumerable<t>();
58 }
59
60 public static ienumerable<t> toenumerable<t>(this datatable dt) where t : class, new()
61 {
62 propertyinfo[] propertyinfos = typeof(t).getproperties();
63 t[] ts = new t[dt.rows.count];
64 int i = 0;
65 foreach (datarow row in dt.rows)
66 {
67 t t = new t();
68 foreach (propertyinfo p in propertyinfos)
69 {
70 if (dt.columns.indexof(p.name) != -1 && row[p.name] != dbnull.value)
71 p.setvalue(t, row[p.name], null);
72 }
73 ts[i] = t;
74 i++;
75 }
76 return ts;
77 }
78 }
79 }
ipagedlist：分页接口
1 using system;
2 using system.collections.generic;
3 using system.text;
4
5 namespace data
6 {
7 public interface ipagedlist<t> : ilist<t>
8 {
9 int pageindex { get; }
10 int pagesize { get; }
11 int totalcount { get; }
12 int totalpages { get; }
13 bool haspreviouspage { get; }
14 bool hasnextpage { get; }
15 }
16 }
pagedlist：分页接口的实现
1 using system;
2 using system.collections.generic;
3 using system.linq;
4 using system.text;
5
6 namespace data
7 {
8 /// <summary>
9 /// paged list
10 /// </summary>
11 /// <typeparam name="t">t</typeparam>
12 public class pagedlist<t> : list<t>, ipagedlist<t>
13 {
14 /// <summary>
15 /// ctor
16 /// </summary>
17 /// <param name="source">source</param>
18 /// <param name="pageindex">page index</param>
19 /// <param name="pagesize">page size</param>
20 public pagedlist(iqueryable<t> source, int pageindex, int pagesize)
21 {
22 int total = source.count();
23 this.totalcount = total;
24 this.totalpages = total / pagesize;
25
26 if (total % pagesize > 0)
27 totalpages++;
28
29 this.pagesize = pagesize;
30 this.pageindex = pageindex;
31 this.addrange(source.skip((pageindex - 1) * pagesize).take(pagesize).tolist());
32 }
33
34 /// <summary>
35 /// ctor
36 /// </summary>
37 /// <param name="source">source</param>
38 /// <param name="pageindex">page index</param>
39 /// <param name="pagesize">page size</param>
40 public pagedlist(ilist<t> source, int pageindex, int pagesize)
41 {
42 totalcount = source.count();
43 totalpages = totalcount / pagesize;
44
45 if (totalcount % pagesize > 0)
46 totalpages++;
47
48 this.pagesize = pagesize;
49 this.pageindex = pageindex;
50 this.addrange(source.skip((pageindex - 1) * pagesize).take(pagesize).tolist());
51 }
52
53 /// <summary>
54 /// ctor
55 /// </summary>
56 /// <param name="source">source</param>
57 /// <param name="pageindex">page index</param>
58 /// <param name="pagesize">page size</param>
59 /// <param name="totalcount">total count</param>
60 public pagedlist(ienumerable<t> source, int pageindex, int pagesize, int totalcount)
61 {
62 totalcount = totalcount;
63 totalpages = totalcount / pagesize;
64
65 if (totalcount % pagesize > 0)
66 totalpages++;
67
68 this.pagesize = pagesize;
69 this.pageindex = pageindex;
70 this.addrange(source);
71 }
72
73 public int pageindex { get; private set; }
74 public int pagesize { get; private set; }
75 public int totalcount { get; private set; }
76 public int totalpages { get; private set; }
77
78 public bool haspreviouspage
79 {
80 get { return (pageindex > 0); }
81 }
82 public bool hasnextpage
83 {
84 get { return (pageindex + 1 < totalpages); }
85 }
86 }
87 }
ienumerableextensions：ienumerable分页的扩展
1 using system.collections.generic;
2 using system.linq;
3
4 namespace data
5 {
6 public static class ienumerableextensions
7 {
8 public static pagedlist<tsource> topagelist<tsource>(this ienumerable<tsource> source, int pageindex, int pagesize)
9 {
10 if (pageindex < 1)
11 pageindex = 1;
12 int totalcount = 0;
13 list<tsource> resultlist = new list<tsource>();
14 resultlist = source.skip((pageindex - 1) * pagesize).take(pagesize).tolist(); ;
15 totalcount = source.count();
16 return new pagedlist<tsource>(resultlist, pageindex, pagesize, totalcount);
17 }
18 }
19 }
irepository：数据库仓库访问接口
1 using system;
2 using system.collections.generic;
3 using system.linq;
4 using system.linq.expressions;
5
6 namespace data
7 {
8 public interface irepository<t> where t : baseentity
9 {
10 /// <summary>
11 /// 通过id获取单个实体
12 /// </summary>
13 /// <param name="id"></param>
14 /// <returns></returns>
15 t getbyid(object id);
16 /// <summary>
17 /// 插入单个实体
18 /// </summary>
19 /// <param name="entity">实体</param>
20 /// <returns></returns>
21 bool insert(t entity);
22 /// <summary>
23 /// 插入单个实体并返回id
24 /// </summary>
25 /// <param name="entity"></param>
26 /// <returns></returns>
27 object insertandgetid(t entity);
28 /// <summary>
29 /// 批量插入数据集
30 /// </summary>
31 /// <param name="entities">数据集</param>
32 void insert(ienumerable<t> entities);
33 /// <summary>
34 /// 更新单个实体
35 /// </summary>
36 /// <param name="entity">实体</param>
37 /// <returns></returns>
38 bool update(t entity);
39 /// <summary>
40 /// 批量更新数据集
41 /// </summary>
42 /// <param name="entities"></param>
43 void update(ienumerable<t> entities);
44 /// <summary>
45 /// 删除单个实体
46 /// </summary>
47 /// <param name="entity"></param>
48 /// <returns></returns>
49 bool delete(t entity);
50 /// <summary>
51 /// 批量删除
52 /// </summary>
53 /// <param name="entities">删除的数据集</param>
54 void delete(ienumerable<t> entities);
55 /// <summary>
56 /// 通过id删除实体
57 /// </summary>
58 /// <param name="id"></param>
59 /// <returns></returns>
60 bool deletebyid(object id);
61 /// <summary>
62 /// 通过id（逗号分隔id）批量删除
63 /// </summary>
64 /// <param name="ids"></param>
65 /// <returns></returns>
66 bool deletebyids(object ids);
67 /// <summary>
68 /// 通过id列表批量删除
69 /// </summary>
70 /// <param name="list"></param>
71 /// <returns></returns>
72 bool deletebyidlist(list<object> list);
73 /// <summary>
74 /// 分页查询
75 /// </summary>
76 /// <param name="pageindex">当前页</param>
77 /// <param name="pagesize">每页条数</param>
78 /// <param name="condition">lambda查询条件where</param>
79 /// <param name="ordername">排序字段 默认createtime</param>
80 /// <param name="sortorder">排序方式 asc desc,默认createtime desc</param>
81 /// <returns></returns>
82 ipagedlist<t> getlistforpaging(int pageindex, int pagesize, expression<func<t, bool>> condition = null, string ordername = null, string sortorder = null);
83 /// <summary>
84 /// linq连表查询专用，获取单表所有数据请使用getlist
85 /// </summary>
86 iqueryable<t> table { get; }
87 /// <summary>
88 /// 根据条件查找
89 /// </summary>
90 /// <param name="condition">lambda查询条件where</param>
91 /// <returns></returns>
92 t getentity(expression<func<t, bool>> condition);
93 /// <summary>
94 /// 分页查询(linq分页方式)
95 /// </summary>
96 /// <param name="pageindex">当前页</param>
97 /// <param name="pagesize">页码</param>
98 /// <param name="condition">lambda查询条件where</param>
99 /// <<param name="sort">排序key:排序字段，value:bool,true-desc，false-asc 默认：createtime desc</param>
100 /// <returns></returns>
101 ipagedlist<t> getlistforpaging(int pageindex, int pagesize, expression<func<t, bool>> condition = null, dictionary<string, bool> sort = null);
102 /// <summary>
103 /// 执行原始sql命令
104 /// </summary>
105 /// <param name="commandtext">sql命令</param>
106 /// <param name="parameters">参数</param>
107 /// <returns>影响的记录数</returns>
108 ienumerable<telement> sqlquery<telement>(string sql, params object[] parameters) where telement : class, new();
109 /// <summary>
110 /// 执行sqlcommand
111 /// </summary>
112 /// <param name="sql">sql</param>
113 /// <param name="parameters">参数</param>
114 /// <returns></returns>
115 int executesqlcommand(string sql, params object[] parameters);
116 /// <summary>
117 /// 查询列表,默认返回整个表数据
118 /// </summary>
119 /// <param name="condition">lambda查询条件where</param>
120 /// <returns></returns>
121 list<t> getlist(expression<func<t, bool>> condition = null);
122 }
123 }
efrepository：iefrepository接口实现
1 using microsoft.entityframeworkcore;
2 using system;
3 using system.collections.generic;
4 using system.data;
5 using system.linq;
6 using system.linq.expressions;
7 using system.reflection;
8 using tools.cache;
9
10 namespace data
11 {
12 public class efrepository<t> : irepository<t> where t : baseentity
13 {
14 private dbcontext _context;
15 private dbset<t> _entities;
16 private istaticcachemanager _cachemanager;
17 public efrepository(dbcontext context, istaticcachemanager cachemanager)
18 {
19 this._context = context;
20 _cachemanager = cachemanager;
21 }
22
23 private dbset<t> entities
24 {
25 get
26 {
27 if (_entities == null)
28 {
29 _entities = this._context.set<t>();
30 }
31 return _entities;
32 }
33 }
34 /// <summary>
35 /// linq连表查询专用，获取单表所有数据请使用getlist
36 /// </summary>
37 public virtual iqueryable<t> table
38 {
39 get {
40 return this.entities;
41 }
42 }
43 /// <summary>
44 /// 通过id获取单个实体
45 /// </summary>
46 /// <param name="id"></param>
47 /// <returns></returns>
48 public virtual t getbyid(object id)
49 {
50 var cachekey = typeof(t).name+".getbyid."+id;
51 return _cachemanager.get(cachekey, ()=>this.entities.find(id));
52 }
53 /// <summary>
54 /// 插入单个实体
55 /// </summary>
56 /// <param name="entity">实体</param>
57 /// <returns></returns>
58 public virtual bool insert(t entity)
59 {
60 if (entity == null)
61 throw new argumentnullexception(nameof(entity));
62
63 try
64 {
65 entities.add(entity);
66 _context.savechanges();
67 var cachecontain = typeof(t).name;
68 _cachemanager.removebycontain(cachecontain);
69 }
70 catch (dbupdateexception exception)
71 {
72 //ensure that the detailed error text is saved in the log
73 throw new exception(getfullerrortextandrollbackentitychanges(exception), exception);
74 }
75 return true;
76 }
77 /// <summary>
78 /// 插入单个实体并返回id
79 /// </summary>
80 /// <param name="entity"></param>
81 /// <returns></returns>
82 public virtual object insertandgetid(t entity)
83 {
84 if (entity == null)
85 throw new argumentnullexception(nameof(entity));
86 try
87 {
88 this.entities.add(entity);
89 this._context.savechanges();
90 var cachecontain = typeof(t).name;
91 _cachemanager.removebycontain(cachecontain);
92 }
93 catch (dbupdateexception exception)
94 {
95 //ensure that the detailed error text is saved in the log
96 throw new exception(getfullerrortextandrollbackentitychanges(exception), exception);
97 }
98 return entity.id;
99 }
100 /// <summary>
101 /// 批量插入数据集
102 /// </summary>
103 /// <param name="entities">数据集</param>
104 public virtual void insert(ienumerable<t> entities)
105 {
106 if (entities == null)
107 throw new argumentnullexception(nameof(entities));
108
109 try
110 {
111 entities.addrange(entities);
112 _context.savechanges();
113 var cachecontain = typeof(t).name;
114 _cachemanager.removebycontain(cachecontain);
115 }
116 catch (dbupdateexception exception)
117 {
118 //ensure that the detailed error text is saved in the log
119 throw new exception(getfullerrortextandrollbackentitychanges(exception), exception);
120 }
121 }
122 /// <summary>
123 /// 更新单个实体
124 /// </summary>
125 /// <param name="entity">实体</param>
126 /// <returns></returns>
127 public virtual bool update(t entity)
128 {
129 if (entity == null)
130 throw new argumentnullexception(nameof(entity));
131 try
132 {
133 this._context.set<t>().attach(entity);
134 type _type = typeof(t);
135 propertyinfo[] _properties = _type.getproperties();
136 var entry = _context.entry(entity);
137 foreach (propertyinfo item in _properties)
138 {
139 if ("id" == item.name || "createtime" == item.name || "createperson" == item.name)
140 {
141 continue;
142 }
143
144 entry.property(item.name).ismodified = true;
145 }
146 this._context.savechanges();
147 var cachecontain = typeof(t).name;
148 _cachemanager.removebycontain(cachecontain);
149 }
150 catch (dbupdateexception exception)
151 {
152 //ensure that the detailed error text is saved in the log
153 throw new exception(getfullerrortextandrollbackentitychanges(exception), exception);
154 }
155 return true;
156 }
157 /// <summary>
158 /// 批量更新数据集
159 /// </summary>
160 /// <param name="entities"></param>
161 public virtual void update(ienumerable<t> entities)
162 {
163 if (entities == null)
164 throw new argumentnullexception(nameof(entities));
165
166 try
167 {
168 // entities.updaterange(entities);
169 this._context.set<t>().attachrange(entities);
170 foreach (var entity in entities)
171 {
172 type _type = typeof(t);
173 propertyinfo[] _properties = _type.getproperties();
174 var entry = _context.entry(entity);
175 foreach (propertyinfo item in _properties)
176 {
177 if ("id" == item.name || "createtime" == item.name || "createperson" == item.name)
178 {
179 continue;
180 }
181
182 entry.property(item.name).ismodified = true;
183 }
184 }
185
186 _context.savechanges();
187 var cachecontain = typeof(t).name;
188 _cachemanager.removebycontain(cachecontain);
189 }
190 catch (dbupdateexception exception)
191 {
192 //ensure that the detailed error text is saved in the log
193 throw new exception(getfullerrortextandrollbackentitychanges(exception), exception);
194 }
195 }
196 /// <summary>
197 /// 删除单个实体
198 /// </summary>
199 /// <param name="entity"></param>
200 /// <returns></returns>
201 public virtual bool delete(t entity)
202 {
203 if (entity == null)
204 throw new argumentnullexception(nameof(entity));
205
206 try
207 {
208 entities.remove(entity);
209 _context.savechanges();
210 var cachecontain = typeof(t).name;
211 _cachemanager.removebycontain(cachecontain);
212 }
213 catch (dbupdateexception exception)
214 {
215 //ensure that the detailed error text is saved in the log
216 throw new exception(getfullerrortextandrollbackentitychanges(exception), exception);
217 }
218 return true;
219 }
220 /// <summary>
221 /// 批量删除
222 /// </summary>
223 /// <param name="entities">删除的数据集</param>
224 public virtual void delete(ienumerable<t> entities)
225 {
226 if (entities == null)
227 throw new argumentnullexception(nameof(entities));
228
229 try
230 {
231 entities.removerange(entities);
232 _context.savechanges();
233 var cachecontain = typeof(t).name;
234 _cachemanager.removebycontain(cachecontain);
235 }
236 catch (dbupdateexception exception)
237 {
238 //ensure that the detailed error text is saved in the log
239 throw new exception(getfullerrortextandrollbackentitychanges(exception), exception);
240 }
241 }
242 /// <summary>
243 /// 通过id删除实体
244 /// </summary>
245 /// <param name="id"></param>
246 /// <returns></returns>
247 public virtual bool deletebyid(object id)
248 {
249 try
250 {
251 var item = this.entities.find(id);
252 if (item == null)
253 {
254 return false;
255 }
256 this.entities.remove(item);
257 this._context.savechanges();
258 var cachecontain = typeof(t).name;
259 _cachemanager.removebycontain(cachecontain);
260 }
261 catch (dbupdateexception exception)
262 {
263 //ensure that the detailed error text is saved in the log
264 throw new exception(getfullerrortextandrollbackentitychanges(exception), exception);
265 }
266 return true;
267 }
268 /// <summary>
269 /// 通过id（逗号分隔id）批量删除
270 /// </summary>
271 /// <param name="ids"></param>
272 /// <returns></returns>
273 public virtual bool deletebyids(object ids)
274 {
275 try
276 {
277 var idarray = ids.tostring().split(',');
278 for (int i = 0; i < idarray.length; i++)
279 {
280 var item = this.entities.find(idarray[i]);
281 if (item == null)
282 {
283 continue;
284 }
285 this.entities.remove(item);
286 }
287 this._context.savechanges();
288 var cachecontain = typeof(t).name;
289 _cachemanager.removebycontain(cachecontain);
290 }
291 catch (dbupdateexception exception)
292 {
293 //ensure that the detailed error text is saved in the log
294 throw new exception(getfullerrortextandrollbackentitychanges(exception), exception);
295 }
296 return true;
297 }
298 /// <summary>
299 /// 通过id列表批量删除
300 /// </summary>
301 /// <param name="list"></param>
302 /// <returns></returns>
303 public virtual bool deletebyidlist(list<object> list)
304 {
305 try
306 {
307 for (int i = 0; i < list.count; i++)
308 {
309 var item = this.entities.find(list[i]);
310 if (item == null)
311 {
312 continue;
313 }
314 this.entities.remove(item);
315 }
316 this._context.savechanges();
317 var cachecontain = typeof(t).name;
318 _cachemanager.removebycontain(cachecontain);
319 }
320 catch (dbupdateexception exception)
321 {
322 //ensure that the detailed error text is saved in the log
323 throw new exception(getfullerrortextandrollbackentitychanges(exception), exception);
324 }
325 return true;
326 }
327
328 /// <summary>
329 /// 根据条件查找
330 /// </summary>
331 /// <param name="condition">lambda查询条件where</param>
332 /// <returns></returns>
333 public virtual t getentity(expression<func<t, bool>> condition)
334 {
335 var cachekey = typeof(t) + "getsingleordefault.condition."+ condition.tostring();
336 return _cachemanager.get(cachekey,()=>this.entities.where(condition).singleordefault());
337 }
338 /// <summary>
339 /// 分页查询(linq分页方式)
340 /// </summary>
341 /// <param name="pageindex">当前页</param>
342 /// <param name="pagesize">页码</param>
343 /// <param name="condition">lambda查询条件where</param>
344 /// <param name="sort">排序key:排序字段，value:bool,true-desc，false-asc，默认：createtime desc</param>
345 /// <returns></returns>
346 public virtual ipagedlist<t> getlistforpaging(int pageindex, int pagesize, expression<func<t, bool>> condition = null, dictionary<string, bool> sort = null)
347 {
348 if (pageindex < 1)
349 pageindex = 1;
350 var cachekey = typeof(t).name;
351 cachekey = cachekey + ".getlist";
352 list<t> data = null;
353
354 if (condition != null)
355 {
356 cachekey = cachekey+ ".condition." + condition.tostring();
357 }
358
359 data = _cachemanager.get<list<t>>(cachekey);
360
361 if(data != null)
362 {
363 if (sort != null)
364 {
365 foreach (var item in sort)
366 {
367 data = data.asqueryable().orderby(item.key, item.value).tolist();
368 }
369 }
370 else
371 {
372 data = data.asqueryable().orderbydescending(x => x.createtime).tolist();
373 }
374 }
375 else
376 {
377 if(condition!=null)
378 {
379 data = this.entities.where(condition).tolist();
380 }
381 else
382 {
383 data = this.entities.tolist();
384 }
385 _cachemanager.set(cachekey, data, 60);
386
387 data = data.asqueryable().orderbydescending(x => x.createtime).tolist();//无缓存默认返回排序后数据
388 }
389
390 return new pagedlist<t>(data, pageindex, pagesize);
391 }
392
393 /// <summary>
394 /// 执行原始sql命令
395 /// </summary>
396 /// <param name="commandtext">sql命令</param>
397 /// <param name="parameters">参数</param>
398 /// <returns>影响的记录数</returns>
399 public virtual ienumerable<telement> sqlquery<telement>(string sql, params object[] parameters) where telement : class, new()
400 {
401 datatable dt = this._context.database.sqlquery(sql, parameters);
402 return dt.toenumerable<telement>();
403
404 }
405 /// <summary>
406 /// 分页查询
407 /// </summary>
408 /// <param name="pageindex">当前页</param>
409 /// <param name="pagesize">每页条数</param>
410 /// <param name="condition">lambda查询条件where</param>
411 /// <param name="ordername">排序字段 默认createtime</param>
412 /// <param name="sortorder">排序方式 asc desc,默认createtime desc</param>
413 /// <returns></returns>
414 public virtual ipagedlist<t> getlistforpaging(int pageindex, int pagesize, expression<func<t, bool>> condition = null, string ordername = null, string sortorder = null)
415 {
416 var cachekey = typeof(t).name;
417 if (pageindex < 1)
418 pageindex = 1;
419 if (ordername == null)
420 {
421 ordername = "createtime";
422 }
423 bool isdesc = true;
424 if(sortorder!=null&&sortorder.tolower() == "asc")
425 {
426 isdesc = false;
427 }
428
429 cachekey = cachekey + ".getlist";
430
431 if(condition!=null)
432 {
433 cachekey = cachekey + ".condition." + condition.tostring();
434 }
435
436 list<t> resultlist = null;
437
438 var cachedata = _cachemanager.get<list<t>>(cachekey);
439 if (cachedata != null)
440 {
441 resultlist = cachedata.asqueryable().orderby(ordername, isdesc).tolist();
442 }
443 else
444 {
445 if (condition == null)
446 {
447 resultlist = entities.tolist();
448 }
449 else
450 {
451 resultlist = entities.where(condition).tolist();
452 }
453 _cachemanager.set(cachekey, resultlist, 60);
454 }
455
456 return new pagedlist<t>(resultlist, pageindex, pagesize);
457 }
458 /// <summary>
459 /// 执行sqlcommand
460 /// </summary>
461 /// <param name="sql">sql</param>
462 /// <param name="parameters">参数</param>
463 /// <returns></returns>
464 public virtual int executesqlcommand(string sql, params object[] parameters)
465 {
466 var result = this._context.database.executesqlcommand(sql, parameters);
467 return result;
468 }
469 /// <summary>
470 /// 查询列表,默认返回整个表数据
471 /// </summary>
472 /// <param name="condition">lambda查询条件where</param>
473 /// <returns></returns>
474 public virtual list<t> getlist(expression<func<t, bool>> condition = null)
475 {
476 var cachekey = typeof(t).name+ ".getlist";
477 list<t> entities = null;
478 if (condition != null)
479 {
480 cachekey = cachekey + ".condition." + condition.tostring();
481 entities = _cachemanager.get(cachekey,()=>this.entities.where(condition).tolist());
482 }
483 else
484 {
485 entities = _cachemanager.get(cachekey,()=>this.entities.tolist());
486 }
487 return entities;
488 }
489 #region utilities
490
491 /// <summary>
492 /// rollback of entity changes and return full error message
493 /// </summary>
494 /// <param name="exception">exception</param>
495 /// <returns>error message</returns>
496 protected string getfullerrortextandrollbackentitychanges(dbupdateexception exception)
497 {
498 //rollback entity changes
499 if (_context is dbcontext dbcontext)
500 {
501 var entries = dbcontext.changetracker.entries()
502 .where(e => e.state == entitystate.added || e.state == entitystate.modified).tolist();
503
504 entries.foreach(entry =>
505 {
506 try
507 {
508 entry.state = entitystate.unchanged;
509 }
510 catch (invalidoperationexception)
511 {
512 // ignored
513 }
514 });
515 }
516
517 try
518 {
519 _context.savechanges();
520 return exception.tostring();
521 }
522 catch (exception ex)
523 {
524 //if after the rollback of changes the context is still not saving,
525 //return the full text of the exception that occurred when saving
526 return ex.tostring();
527 }
528 }
529
530 #endregion
531
532 }
533 }
534 public static class queryableextensions
535 {
536 public static iqueryable<t> orderby<t>(this iqueryable<t> queryable, string propertyname)
537 {
538 return queryablehelper<t>.orderby(queryable, propertyname, false);
539 }
540 public static iqueryable<t> orderby<t>(this iqueryable<t> queryable, string propertyname, bool desc)
541 {
542 return queryablehelper<t>.orderby(queryable, propertyname, desc);
543 }
544 static class queryablehelper<t>
545 {
546 private static dictionary<string, lambdaexpression> cache = new dictionary<string, lambdaexpression>();
547 public static iqueryable<t> orderby(iqueryable<t> queryable, string propertyname, bool desc)
548 {
549 dynamic keyselector = getlambdaexpression(propertyname);
550 return desc ? queryable.orderbydescending(queryable, keyselector) : queryable.orderby(queryable, keyselector);
551 }
552 private static lambdaexpression getlambdaexpression(string propertyname)
553 {
554 if (cache.containskey(propertyname)) return cache[propertyname];
555 var param = expression.parameter(typeof(t));
556 var body = expression.property(param, propertyname);
557 var keyselector = expression.lambda(body, param);
558 cache[propertyname] = keyselector;
559 return keyselector;
560 }
561 }
562 }
_cachemanager下篇我们讲到缓存管理的时候再来讲，包括依赖注入也放到下篇，今天就先到这里了！
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