EntityFramework 动态构造排序 Func<IQueryable<T>, IOrderedQueryable<T>> Dynamic

using System;
using System.Collections.Generic;
using System.Linq;
using System.Linq.Expressions;
using System.Reflection;
using System.Text;
/**
*
* jackchain
* QQ:710782046
* 2017-08-31
* 动态构造OrderBy Linq序列
*
*/

namespace UFX.Tools
{
public class ConvertExtOrderLinq
{
/// <summary>
/// 动态转换为Linq排序
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="orderList">[aaa,bbb,ccc],[asc,asc,desc]</param>
/// <returns></returns>
public static Func<IQueryable<T>, IOrderedQueryable<T>> GetOrderBy<T>(List<string> orderColumn, List<string> orderDir)
{
string ascKey = "OrderBy";
string descKey = "OrderByDescending";

Type typeQueryable = typeof(IQueryable<T>);
ParameterExpression argQueryable = Expression.Parameter(typeQueryable, "jk");
var outerExpression = Expression.Lambda(argQueryable, argQueryable);

for (int i = 0; i < orderColumn.Count; i++)
{
string columnName = orderColumn[i];
string dirKey = orderDir[i].ToLower();

IQueryable<T> query = new List<T>().AsQueryable<T>();
Type type = typeof(T);
ParameterExpression arg = Expression.Parameter(type, "uf");
Expression expr = arg;

if (columnName.Contains("."))
{
// support to be sorted on child fields.
String[] childProperties = columnName.Split('.');
System.Reflection.PropertyInfo property = typeof(T).GetProperty(childProperties[0]);
MemberExpression propertyAccess = Expression.MakeMemberAccess(arg, property);

for (int j = 1; j < childProperties.Length; j++)
{
Type t = property.PropertyType;
if (!t.IsGenericType)
{
property = t.GetProperty(childProperties[j]);
}
else
{
property = t.GetGenericArguments().First().GetProperty(childProperties[i]);
}
type = property.PropertyType;
expr = Expression.MakeMemberAccess(propertyAccess, property);
//propertyAccess = Expression.MakeMemberAccess(propertyAccess, property);
}
//property = type.GetProperty(propertyName);
//propertyAccess = Expression.MakeMemberAccess(parameter, property);
}
else
{
PropertyInfo pi = type.GetProperty(columnName, BindingFlags.IgnoreCase | BindingFlags.Public | BindingFlags.Instance);
expr = Expression.Property(expr, pi);
type = pi.PropertyType;
}

LambdaExpression lambda = Expression.Lambda(expr, arg);
string methodName = dirKey == "asc" ? ascKey : descKey;
MethodCallExpression resultExp = Expression.Call(typeof(Queryable), methodName, new Type[] { typeof(T), type }, outerExpression.Body, Expression.Quote(lambda));

outerExpression = Expression.Lambda(resultExp, argQueryable);

ascKey = "ThenBy";
descKey = "ThenByDescending";
}
return (Func<IQueryable<T>, IOrderedQueryable<T>>)outerExpression.Compile();
}

}
}

[Action]
[Description("获取Grid数据")]
[HttpPost]
public JsonResult Get(int start, int length, ExtGridSearch condition, ExtGridMutiSearch[] extCdns, ExtGridOrder[] order)
{
int totalCount = 0;

Func<IQueryable<DB_Color>, IOrderedQueryable<DB_Color>> dyncOrder = ConvertExtOrderLinq.GetOrderBy<DB_Color>(order.Select(s => s.column).ToList(), order.Select(s => s.dir).ToList());
var list = WMFactory.DBColor.FindByPage(start, length, out totalCount,
dyncOrder,
null, condition, extCdns);
return Json(new { data = list, recordsTotal = totalCount, recordsFiltered = totalCount }, JsonRequestBehavior.AllowGet);
}

//主表格
var DBRangeGrid = $('#DBRangeGrid').dataTable(
{
scrollY: Global_MainTableHeight,
scrollX: true,
autoWidth: true,
scrollCollapse: false,
"processing": true,
"serverSide": true,
"ajax": {
"url": "/Admin/Range/Get",
"type": "POST",
"data": function (d) {
var dtCols = $('#DBRangeGrid').DataTable().settings().init().columns;
var extOrder = [];
var dtOrders = $('#DBRangeGrid').DataTable().order();
$.each(dtOrders, function (i, item) {
extOrder.push({ column: dtCols[item[0]].data, dir: item[1] });
})
d.order = extOrder;
d.query = $("#txtSearchKey").val();
d.fields = ['IsEnable', 'Year.YearName', 'Season.SeasonName', 'RangeName', 'Remark', 'CreateUser', ];
}
},
"ordering": true,
"order": [[8, "desc"]],
"columns": [
{
"class": "cbcenter",
"orderable": false,
"title": '<input type="checkbox" title="全选" class="selectAll" />',
"data": "Id",
"width": "30px",
"render": function (data, type, row) {
return '<input type="checkbox" class="ckbox" />';
}
},
{
"title": "启用", "data": "IsEnable", render: function (data, tp, row) {

if (row.IsEnable == 1) {
return "<span style='color:green'>启用</span>";
} else {
return "<span style='color:red'>禁用</span>";
}
}
},
{ "title": "年份", "data": "Year.YearName" },
{ "title": "季节", "data": "Season.SeasonName" },
{ "title": "月份", "data": "Month" },
{ "title": "波段名称", "data": "RangeName" },
{ "title": "备注", "data": "Remark" },
{
"data": "CreateUser", "title": "操作人", "width": "40px", "render": function (data, type, record) {
if (record.ModifyUser != undefined && record.ModifyUser != "" && record.ModifyUser != null) return record.ModifyUser;
else return data;
}
},
{
"data": "CreateTime", "title": "操作时间", "width": "120px", "render": function (data, type, record) {
if (record.ModifyTime != undefined && record.ModifyTime != "" && record.ModifyTime != null) data = record.ModifyTime;
var dt = eval("new " + data.substr(1, data.length - 2));
return dt.Format("yyyy-MM-dd hh:mm:ss");
}
}
]
});