using System;

using System.Linq;

using System.Collections.Generic;

​

public class Program

{

    public void Main()

    {             

        var John="test";

        IList<Item> items = new List<Item>();

        items.Add(new Item

        {

             tag = "{Ann}",

             value = "Anny"

        });

        items.Add(new Item

        {

             tag = "{"+John+"}",

             value = "Johnny"

        }); 

        items.Where(o => o.tag == "{"+John+"}").ToList().ForEach(item =>{

        item.value = "jane";

        });

        items.ToList().ForEach(item => {

            Console.WriteLine(item.tag+"="+item.value);

        });

    }   

}

​

public class Item{

    public string tag {get;set;}

    public string value {get;set;}

​

}

​

​

​