如何在EntityFramework中按动态列名排序
本文关键字:动态 排序 EntityFramework | 更新日期: 2023-09-27 17:52:45
我试图得到以下代码工作,这是工作良好的MSSQL,但因为我改变使用mySql它不工作
records.Content = db.areas
.Where(x => x.Name.Contains(filter)))
.OrderBy("dated desc")
.ToList();
我得到错误"无法加载一个或多个请求的类型"。获取LoaderExceptions属性以获取更多信息。"
string colName = "datedD" ;
如何根据colName变量进行排序?
'
在。net Core中,我们可以使用EF.Property
方法将属性的名称指定为字符串:
string sortColumn = "Price";
//IQueryable<Product> q = from p in myDbContext.Products select p;
q = q.OrderBy(p => EF.Property<object>(p, sortColumn));
试试这个
string filterString = "dated";
bool isAscSorting = false;
Func<dynamic, dynamic> orderingFunction = i =>
filterString == "dated" ? i.dated :
filterString == "something" ? i.columnx : "";
records.Content = (isAscSorting) ?
db.areas
.Where(x => x.Name.Contains(filter)))
.OrderBy(orderingFunction)
.ToList()
:
db.areas
.Where(x => x.Name.Contains(filter)))
.OrderByDescending(orderingFunction)
.ToList();
我使用了@NEER和@S的两个答案的组合。serposhan避免LINQ查询
IQueryable<area> filteredItems = db.areas.Where(x => x.Name.Contains(filter)));
IQueryable<area> orderedItems;
if (IsAscending)
{
orderedItems = filteredItems.OrderBy(item => typeof(area).GetProperty(colName).GetValue(item).ToString());
}
else
{
orderedItems = filteredItems.OrderByDescending(item => typeof(area).GetProperty(colName).GetValue(item).ToString());
}
糟糕的是——我的代码将项目作为字符串进行比较。我没有时间让它更"友好",但我很确定这是可能的。
对于动态排序,我找到了最方便的方法:
string propertyNameForOrdering = "UserName";
var list = context.Customers.OrderByDescendingDynamic(x => "x." + propertyNameForOrdering).ToList(); // DESC
var list = context.Customers.OrderByDynamic(x => "x." + propertyNameForOrdering).ToList(); // ASC
Entity Framework Plus Library - Linq-Dynamic