using System;

using System.Linq.Expressions;

using System.Threading.Tasks;

using System.Linq;

using System.Collections.Generic;

​

​

public class Program

{

    public static void Main(string[] args)

    {

        var criterias = new Dictionary<string, object>();

        //criterias.Add("abc", ...

        object entityValue;

        bool useEntityKey = criterias.TryGetValue("abc", out entityValue);

        string aaa = entityValue.ToString();

    }

​

​

}

​