[英]How to perform a LINQ where clause with a dynamic column
I am attempting to use System.Linq.Dynamic.Core ( https://github.com/StefH/System.Linq.Dynamic.Core ) in order to create dynamic queries.我正在尝试使用 System.Linq.Dynamic.Core ( https://github.com/StefH/System.Linq.Dynamic.Core ) 来创建动态查询。
Following the example given on the github page, I have tried the following按照github页面上给出的示例,我尝试了以下操作
lstContacts = lstContacts.Where("@0 == true", "active");
However I get the following result: 'active is not a valid value for Boolean但是我得到以下结果:'active is not a valid value for Boolean
Reference this library:参考这个库:
using System.Linq.Dynamic;
And make your query like that:并像这样进行查询:
string columnName = "active";
var lstContacts = lstContacts.Where(columnName + " == true");
Here is a working example:这是一个工作示例:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Linq.Dynamic;
public class Program
{
public static void Main()
{
var lstContacts = new List<Contact>{
new Contact{Id = 1, Active = true, Name = "Chris"},
new Contact{Id = 2, Active = true, Name = "Scott"},
new Contact{Id = 3, Active = true, Name = "Mark"},
new Contact{Id = 4, Active = false, Name = "Alan"}};
string columnName = "Active";
List<Contact> results = lstContacts.Where(String.Format("{0} == true", columnName)).ToList();
foreach (var item in results)
{
Console.WriteLine(item.Id.ToString() + " - " + item.Name.ToString());
}
}
}
public class Contact
{
public int Id
{
get;
set;
}
public bool Active
{
get;
set;
}
public string Name
{
get;
set;
}
}
You can experiment with this .net-fiddle-here你可以在这里试验这个.net-fiddle-here
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