如下图查询页面，跟据不同条件动态生成lambda的Where条件和OrderBy,如果要增加或调整查询，只用改前台HTML即可，不用改后台代码
前台代码：
1 <div style="padding-bottom: 5px;" id="queryForm">
2
3 <span>员工姓名：</span><input type="text" emptytext="ddd" data-options="{match:‘in‘}" class="mini-textbox" id="Age" />
4 <span>部门：</span><input type="text" class="mini-textbox" data-options="{match:‘like‘}" id="Sex" />
5
6 生日从 <input id="beg" format="yyyy-MM-dd" showokbutton="false" showclearbutton="true" data-options="{match:‘from‘,innerkey:‘Birthday‘}" class="mini-datepicker" />
7 至 <input id="end" format="yyyy-MM-dd" showokbutton="false" showclearbutton="true" data-options="{match:‘to‘,innerkey:‘Birthday‘}" class="mini-datepicker" />
8
9 <span>年龄从：</span><input type="text" emptytext="ddd" data-options="{match:‘from‘,innerkey:‘Age‘}" class="mini-textbox" id="bb" />
10 <span>至：</span><input type="text" class="mini-textbox" data-options="{match:‘to‘,innerkey:‘Age‘}" id="bd" />
11
12 <a class="mini-button" iconcls="icon-search" onclick="search()">查找</a>
13
14
15 </div>
16
17
18 <div id="datagrid1" ondrawcell="Link" onupdate="load" class="mini-datagrid" style="width: 100%; height: 100%;" allowresize="true"
19 idfield="Id" sortfield="Age" showpager="false" pagesize="-1" sizelist="[-1]" sortorder="asc" multiselect="true">
20 <div property="columns">
21 <!--<div type="indexcolumn"></div> -->
22 <div type="checkcolumn"></div>
23 <div field="UserName" data-options="{Func:‘test‘}" width="120" headeralign="center" allowsort="true">姓名</div>
24 <div field="Sex" renderer="SexShow" width="120" headeralign="center" allowsort="true">性别</div>
25
26 <div field="LoginName" width="120">登录名</div>
27 <div field="Password" width="120">密码</div>
28 <div field="Birthday" width="100">生日</div>
29 <div field="Age" width="100" allowsort="true">年龄</div>
30 <div field="Remark" align="right" width="100">备注</div>
31
32
33 <div field="Married" renderer="MarriedShow" width="100">婚否</div>
34
35 </div>
36 </div>
查询控件上的 data-options="{match:‘from‘,innerkey:‘Birthday‘}" 后多个查询条件会组合成一个json数组，传到后台，反序列化成List<QueryItem>,排序条件Jquery 的Grid控件也会传到后台的，反序列化成SortItem，分页信息 反序列化成 Pager，详见后台代码。
上后台代码：比较复杂
1 using System;
2 using System.Collections.Generic;
3 using System.Linq;
4 using System.Text;
5 using System.Threading.Tasks;
6 using App.Core;
7 using System.Reflection;
8 using System.Linq.Expressions;
9 using System.Data.Entity;
10 using System.Collections.Specialized;
11 namespace App.PageBase.Query
12 {
13 //查询条件模型
14 public class QueryItem
15 {
16 public string match { get; set; }
17 public string value { get; set; }
18 public string key { get; set; }
19 public string innerkey { get; set; }
20
21 }
22 //排序模型
23 public class SortItem
24 {
25
26 public string sortField { get; set; }
27 public string sortOrder { get; set; }
28 }
29 //列表分页模型
30 public class Pager
31 {
32 public int pageSize
33 {
34 get;
35 set;
36 }
37 public int pageIndex
38 {
39 get;
40 set;
41 }
42 public int totalCount
43 {
44 get;
45 set;
46 }
47
48 }
49
50
51 //生成查询条件类
52 public class QueryBulider<TEntity> where TEntity : class,new()
53 {
54 private Pager _pager;// = new Pager();
55 private SortItem _sort;// = new SortItem();
56 private List<QueryItem> _queryItems;//= new List<QueryItem>();
57 public Pager pager
58 {
59 get { return _pager; }
60 set { _pager = value; }
61 }
62 public SortItem sort
63 {
64 get { return _sort; }
65 set { _sort = value; }
66 }
67 public List<QueryItem> queryItems
68 {
69 get { return _queryItems; }
70 set { _queryItems = value; }
71 }
72 /// <summary>
73 /// 根据 分页模型，排序模型，查询条件模型列表构造 自动查询生成器
74 /// </summary>
75 /// <param name="pager"></param>
76 /// <param name="sort"></param>
77 /// <param name="queryItems"></param>
78 public QueryBulider(Pager pager, SortItem sort, List<QueryItem> queryItems)
79 {
80 this.pager = pager;
81 this.sort = sort;
82 this.queryItems = queryItems;
83
84
85 }
86 public QueryBulider()
87 { }
88
89 /// <summary>
90 /// 根据HTTP实例化
91 /// </summary>
92 /// <param name="requstForm"></param>
93 public QueryBulider(NameValueCollection requstForm)
94 {
95 string filter = requstForm["filter"];
96 string pageIndex = requstForm["pageIndex"];
97 string pageSize = requstForm["pageSize"];
98 string sortField = requstForm["sortField"];
99 string sortOrder = requstForm["sortOrder"];
100
101 if (!string.IsNullOrEmpty(pageSize) && !string.IsNullOrEmpty(pageIndex)&&pageSize!="-1")
102 {
103 this.pager = new Pager { pageIndex = int.Parse( pageIndex), pageSize = int.Parse( pageSize) };
104 }
105 if (!string.IsNullOrEmpty(sortField))
106 {
107 this.sort = new SortItem { sortField = sortField, sortOrder = sortOrder };
108 }
109 if (!string.IsNullOrEmpty(filter))
110 {
111 this.queryItems = JsonHelper.Json2Object<List<QueryItem>>(filter);
112 }
113
114 }
115 //生成常量表达式
116 private ConstantExpression GetValueConstant(string value, Type type)
117 {
118 string typeName = type.Name.ToLower();
119 ConstantExpression rtn = null;
120 switch (typeName)
121 {
122 case "int32":
123 int intValue;
124 if (!int.TryParse(value, out intValue))
125 {
126 rtn = Expression.Constant(false);
127 }
128 else
129 {
130 rtn = Expression.Constant(intValue);
131
132 }
133 break;
134 case "string":
135
136 rtn = Expression.Constant(value);
137 break;
138 case "float":
139 float fValue;
140 if (!float.TryParse(value, out fValue))
141 {
142 rtn = Expression.Constant(false);
143 }
144 else
145 {
146 rtn = Expression.Constant(fValue);
147
148 }
149 break;
150 case "single":
151 Single sgValue;
152 if (!Single.TryParse(value, out sgValue))
153 {
154 rtn = Expression.Constant(false);
155 }
156 else
157 {
158 rtn = Expression.Constant(sgValue);
159
160 }
161 break;
162 case "decimal":
163 decimal dcValue;
164 if (!decimal.TryParse(value, out dcValue))
165 {
166 rtn = Expression.Constant(false);
167 }
168 else
169 {
170 rtn = Expression.Constant(dcValue);
171
172 }
173 break;
174 case "double":
175 double dbValue;
176 if (!double.TryParse(value, out dbValue))
177 {
178 rtn = Expression.Constant(false);
179 }
180 else
181 {
182 rtn = Expression.Constant(dbValue);
183
184 }
185 break;
186 case "datetime":
187 DateTime dateValue;
188 if (!DateTime.TryParse(value, out dateValue))
189 {
190 rtn = Expression.Constant(false);
191 }
192 else
193 {
194 rtn = Expression.Constant(dateValue);
195
196 }
197 break;
198
199 default:
200 rtn = Expression.Constant(false);
201 break;
202
203
204
205
206 }
207 return rtn;
208
209 }
210
211
212 //生成列表常量表达式 实现 In (‘a‘,‘b‘)
213 private ConstantExpression GetValueListConstant(string value, Type type)
214 {
215 string typeName = type.GenericTypeArguments.Length == 0 ? type.Name : type.GenericTypeArguments[0].Name;
216 ConstantExpression rtn = null;
217 switch (typeName.ToLower())
218 {
219 case "int32":
220 int intValue;
221 string[] arrInt = value.Split(‘,‘);
222 List<int> dlInt = new List<int>();
223 foreach (string a in arrInt)
224 {
225 if (int.TryParse(a, out intValue))
226 {
227 dlInt.Add(intValue);
228 }
229
230 }
231 if (dlInt.Count == 0)
232 {
233 rtn = Expression.Constant(false);
234
235 }
236 else
237 {
238 rtn = Expression.Constant(dlInt);
239 }
240
241 break;
242 case "string":
243 List<string> dlStr = value.Split(‘,‘).ToList();
244 if (dlStr.Count == 0)
245 {
246 rtn = Expression.Constant(false);
247
248 }
249 else
250 {
251 rtn = Expression.Constant(dlStr);
252 }
253 break;
254
255
256 default:
257 rtn = Expression.Constant(false);
258 break;
259
260
261
262
263 }
264 return rtn;
265
266 }
267
268
269 /// <summary>
270 /// 根据前台查询字段自动生成Lambad(支持=，like,between,in 查询)
271 /// </summary>
272 /// <returns></returns>
273 public Expression<Func<TEntity, bool>> BulidWhere()
274 {
275 Type type = typeof(TEntity);
276 string key = "";
277 string value = "";
278 string match = "";
279 string innerkey = "";
280 ParameterExpression instance = Expression.Parameter(type);
281 BinaryExpression result = Expression.Equal(Expression.Constant(true), Expression.Constant(true));
282 if (queryItems == null) return Expression.Lambda<Func<TEntity, bool>>(result, instance);
283 foreach (var item in queryItems)
284 {
285 key = item.key;
286
287 value = item.value;//.ToLower();
288 if (string.IsNullOrEmpty(value)) continue;
289 match = item.match.ToLower();
290 innerkey = !string.IsNullOrEmpty(item.innerkey) ? item.innerkey : key;
291 PropertyInfo propertyInfo = type.GetProperty(innerkey);
292 var proFullType = propertyInfo.PropertyType;
293 Type propertyType = proFullType.GenericTypeArguments.Length == 0 ? proFullType : proFullType.GenericTypeArguments[0];
294 var valueExpression = match == "in" ? this.GetValueListConstant(value, propertyType) : this.GetValueConstant(value, propertyType);
295 MemberExpression propertyExpression = Expression.Property(instance, propertyInfo);
296 if (proFullType.Name.Contains("Nullable"))
297 {
298 propertyExpression = Expression.Property(propertyExpression, "Value");
299 }
300 var falseExpression = (Expression)Expression.Constant(false);
301 if (valueExpression.Value.ToString() == "False")
302 {
303
304 result = Expression.And(result, falseExpression);
305 continue;
306 }
307 switch (match)
308 {
309 case "=":
310 result = Expression.And(result, Expression.Equal(propertyExpression, valueExpression));
311 break;
312 case "like":
313 if (propertyType == typeof(string))
314 {
315 var like = Expression.Call(propertyExpression, typeof(string).GetMethod("Contains"), valueExpression);
316 result = Expression.And(result, like);
317 }
318 else
319 {
320 result = Expression.And(result, falseExpression);
321
322 }
323 break;
324 case "in":
325 if (propertyType == typeof(string) || propertyType == typeof(Int32))
326 {
327 var inExp = Expression.Call(valueExpression, valueExpression.Type.GetMethod("Contains", new Type[] { propertyType }), propertyExpression);
328 result = Expression.And(result, inExp);
329 }
330 else
331 {
332 result = Expression.And(result, falseExpression);
333
334 }
335
336 break;
337 case "from":
338
339 if (propertyType.IsValueType)
340 {
341
342 var from = Expression.GreaterThanOrEqual(propertyExpression, valueExpression);
343 result = Expression.And(result, from);
344 }
345 else
346 {
347 result = Expression.And(result, falseExpression);
348
349 }
350 break;
351 case "to":
352 if (propertyType.IsValueType)
353 {
354
355 var from = Expression.LessThanOrEqual(propertyExpression, valueExpression);
356 result = Expression.And(result, from);
357 }
358 else
359 {
360 result = Expression.And(result, falseExpression);
361
362 }
363 break;
364 }
365 }
366 var lambda = Expression.Lambda<Func<TEntity, bool>>(result, instance);
367 return lambda;
368
369 }
370 }
371 }
这一套自动查询支持对应sql的 In,=,Like ,Between 查询，原理上也支持Not Like, Not In但是一般给用户的查询不会用到这些查询。
扩展EF框架的 DBSet：
1 namespace App.PageBase.Query
2 {
3 // 摘要:
4 // 提供一组用于查询实现 System.Linq.IQueryable<T> 的数据结构的 static（在 Visual Basic 中为 Shared）方法。
5 public static class DbSet
6 {
7 /// <summary>
8 /// 按QueryBulider自动生成 过滤，排序,分页
9 /// </summary>
10 /// <typeparam name="T"></typeparam>
11 /// <param name="qb"></param>
12 /// <param name="query"></param>
13 /// <returns></returns>
14 public static IQueryable<T> Query<T>(this DbSet<T> qb, QueryBulider<T> query) where T : class,new()
15 {
16
17 var IQ = qb.Where(query.BulidWhere());
18 if (query.sort == null && query.pager != null)
19 {
20 throw new Exception("列表分页时必须指定排序字段");
21 }
22
23 Type type = typeof(T);
24 var callWhere = IQ.Expression;
25 if (query.sort != null)
26 {
27 var sortFieldProperty = type.GetProperty(query.sort.sortField);
28 var instance =Expression.Parameter(type);
29 var sortFieldExpression = Expression.Property(instance, sortFieldProperty);
30 string OrderName = query.sort.sortOrder;
31 if (OrderName.ToLower() == "desc")
32 {
33 OrderName = "OrderByDescending";
34 }
35 else
36 {
37 OrderName = "OrderBy";
38 }
39
40 Expression.Lambda(sortFieldExpression, instance);
41 callWhere = Expression.Call(typeof(Queryable), OrderName, new Type[] { type, sortFieldProperty.PropertyType }, callWhere, Expression.Lambda(sortFieldExpression, instance));
42 }
43 if (query.pager != null)
44 {
45 IQ = IQ.Provider.CreateQuery<T>(callWhere).Skip(query.pager.pageIndex * query.pager.pageSize).Take(query.pager.pageSize);
46 }
47
48 return IQ;
49
50 }
51
52
53 }
后台页面调用：
var queryBulider = new QueryBulider<UserInfo>(Request.Form);
var dl = db.Set<UserInfo>().Query(queryBulider);
当然前台js组件不同，前台的封装就不一样。MiniUi我是这样弄的。
///组合查询条件
function GetQueryFormData(formId) {
var data = [];
if (!formId) formId = "queryForm";
var form = new mini.Form("#" + formId);
var fields = form.getFields();
var arr = [];
for (var i = 0; i < fields.length; i++) {
var item = {};
item["key"] = fields[i].id;
item["value"] = fields[i].value;
item["match"] = fields[i].match;
item["innerkey"] = fields[i].innerkey;
arr.push(item);
}
return arr;
}
///查询事件
function search() {
var grid = mini.get("datagrid1");
var query = GetQueryFormData();
var json = mini.encode(query);
grid.load({ filter: json });
}
时间： 2024-10-30 12:25:42