using System;

using System.Linq.Expressions;

public class Program

{

    public static void Main()

    {

        var Value1 = "value1";

        var z_objEntity = new EntityTable();

        z_objEntity.CustomWhere1(t => t.Field1 == Value1); // compiles!

    }

    public class CustomBaseTable<T>

    {

         public void CustomWhere1(Expression<Func<T, bool>> p_expWhereClause)

         { 

             throw new NotImplementedException();

         }

    }

    public class EntityTable : CustomBaseTable<EntityTable>

    {

        public string Field1 { get; set; }

    }

}

​