使用复杂对象的c# Lambda表达式

如何在具有列表PaymentFields对象的Payment对象列表上使用Lambda表达式?以下是我目前的资料

var list = paymentList.Where(payment => payment.PaymentFields.Any(field => field.FieldName == "ItemA" && field.FieldValue == "50");

这给了我以ItemA作为字段名，50作为字段值的支付。但是，我想比较两个PaymentFields，像这样…

Where FieldName == "ItemA" && FieldValue = "50" && FieldName ItemA < FieldName ItemB

我该怎么做呢?

有两个对象:

public class Payment
{
    public int Id { set; get; }
    public string Name { set; get; }
    public List<PaymentFields> PaymentFields { set; get; }
}
public class PaymentFields
{
    public string FieldName { set; get; }
    public string FieldValue { set; get; }
}

下面是一个示例对象:

var payment = new Payment()
{
    Id = 1,
    Name = "Test",
    PaymentFields = new List<PaymentFields>()
    {
        new PaymentFields()
        {
            FieldName = "ItemA",
            FieldValue = "20"
         },
         new PaymentFields()
         {
             FieldName = "ItemB",
             FieldValue = "50"
          }
    }
};

谢谢你的帮助!

var list = paymentList
             .Where(payment => payment.PaymentFields.Any(field => field.FieldName == "ItemA" && field.FieldValue == "50")
             .Where(payment => payment.PaymentFields.First(field => field.FieldName == "ItemA").FieldValue
                                   <
                               payment.PaymentFields.First(field => field.FieldName == "ItemB").FieldValue)
                    );