ExpressionSnippet.cs

List<Customer> _customers = new List<Customer>
{
	new Customer { Id = 1, Name = "Customer1" },
	new Customer { Id = 2, Name = "Customer2" },
	new Customer { Id = 3, Name = "Customer3" },
	new Customer { Id = 4, Name = "Customer4" },
	new Customer { Id = 5, Name = "Customer5" },
	new Customer { Id = 6, Name = "Customer6" },
};

void Main()
{
	var customer = Find(_customers, new Customer { Id = 2, Name = "Customer2" });
	
	if (customer != null)
	{
		Console.WriteLine(customer.Name);
	}
	else
	{
		Console.WriteLine("Didn't find any!");
	}
}

T Find<T>(IEnumerable<T> items, T query)
{
	var keys = new[] { "Id", "Name" };
	
	var expressions = new List<Expression>();
	
	var parameter = Expression.Parameter(typeof(T), "x");
	
	foreach (var key in keys)
	{
		var property = typeof(T).GetProperty(key, BindingFlags.Instance | BindingFlags.Public | BindingFlags.IgnoreCase);
		
		if (property == null)
		{
			continue;
		}
		
		var value = property.GetValue(query);
		
		var expression = Expression.Equal(Expression.Property(parameter, key), Expression.Constant(value));
		
		expressions.Add(expression);
	}
	
	var and = expressions.Aggregate((left, right) => Expression.AndAlso(left, right));
	
	var lambda = Expression.Lambda<Func<T, bool>>(and, parameter);
	
	// return items.FirstOrDefault(lambda);
	return Enumerable.FirstOrDefault(items, lambda.Compile());
}

class Customer
{
	public int Id { get; set; }
	
	public string Name { get; set; }
}