Amazon Marketplace XML Parsing with LINQ

Question

I have a number of complex XML files from Amazon showing order reports.

The XML fragment is as follows:

<Order> <AmazonOrderID>000-1111111-2222222</AmazonOrderID> <MerchantOrderID>111-3333333-4444444</MerchantOrderID> <PurchaseDate>2012-03-02T13:28:53+00:00</PurchaseDate> <LastUpdatedDate>2012-03-02T13:29:05+00:00</LastUpdatedDate> <OrderStatus>Pending</OrderStatus> <SalesChannel>Amazon.com</SalesChannel> <URL>http://www.amazon.com</URL> <FulfillmentData> <FulfillmentChannel>Amazon</FulfillmentChannel> <ShipServiceLevel>Standard</ShipServiceLevel> <Address> <City>Beverly Hills</City> <State>CA</State> <PostalCode>90210-1234</PostalCode> <Country>US</Country> </Address> </FulfillmentData> <OrderItem> <ASIN>AmazonASIN </ASIN> <SKU> Internal-SKU</SKU> <ItemStatus>Pending</ItemStatus> <ProductName> This is the name of the product </ProductName> <Quantity>1</Quantity> <ItemPrice> <Component> <Type>Principal</Type> <Amount currency="USD">19.99</Amount> </Component> </ItemPrice> </OrderItem> </Order> 

What I need to do with this file is to extract the various parts of the XML document, and then do a few things with the data.

The problem I am facing consists of several order items.

The following code will correctly grab each node and put it in a list item, however I'm not sure how to associate these multiple items with the same order number in C #.

C # snippet:

 List<string> getNodes(string path, string nodeName) { List<string> nodes = new List<string>(); XDocument xmlDoc = XDocument.Load(path); //Create the XML document type foreach (var el in xmlDoc.Descendants(nodeName)) { //for debugging //nodes.Add(el.Name + " " + el.Value); //for production nodes.Add(el.Value); } return nodes; } //end getNodes 

The method is called as:

 List<string> skuNodes = xml.getNodes(@"AmazonSalesOrders.xml", "SKU"); 

where xml is an instance of the class.

To further explain the complexity: if each node is placed in its own list, the length of the list will be constant if only one item is ordered. After ordering multiple items, SKU lists, quantity, price, etc. Get longer and prevent an easy cycle.

I'm sure there is a LINQ to XML statement that can do what I need, but I'm not so close to experience that C # can crack it.

+++++++++++++++ EDIT ++++++++++++++++++++

I am trying to use some LINQ suggestions that I found on the Internet. The following looks promising, but returns an exception:

 base {System.SystemException} = {"Object reference not set to an instance of an object."} 

the code:

 var query = from xEle in xmlDoc.Descendants(node) where xEle.Element("AmazonOrderID").Value.ToString() == primaryKey select new { tag = xEle.Name.LocalName, value = xEle.Value }; 

I'm not sure why this is happening, the node and primary key variables are passed at runtime.

If I set breakpoints, I see that primaryKey is passed correctly, the same with node; however, when I get to:

 Dictionary<string, string> ordersByID = new Dictionary<string, string>(); foreach (var CurNode in query) { ordersByID.Add(CurNode.tag, CurNode.value); } 

I get a null link error as it parses CurNode.

Answer 1

You can achieve this using linq, as you thought something like this should work, just add more elements if necessary for itemprice, etc .: (Where ns is the namespace)

 xmlDoc = XDocument.Parse(sr.ReadToEnd()); XNamespace ns = "w3.org/2001/XMLSchema-instance"; var query = from order in xmlDoc.Descendants(ns + "Order") from orderItem in order.Elements(ns + "OrderItem") select new { amazonOrdeID = order.Element(ns + "AmazonOrderID").Value, merchantOrderID = order.Element(ns + "MerchantOrderID ").Value, orderStatus = order.Element(ns + "OrderStatus ").Value, asin = orderItem.Element(ns + "ASIN").Value, quantity = orderItem.Element(ns + "quantity").Value }; 

using the above, you can return all the information needed to order an Amazon in a single line ...

Answer 2

Since then, we decided to use an alternative method, so I did not have the opportunity to fully test the solution, I mark it as complete due to a change in direction.