Xdocument descendants first book

Ive also written a number of computer books, including peter nortons assembly language book also anchient history. Solved xdocument problem with descendants codeproject. Aug 31, 2010 overview while working on the biodiversity heritage library bhl, i have incorporated the open source book viewer software from openlibrary. Example open a blank document that is stored as a base64 string. Using the setattributevalue, set attribute name as pub and value as shree.

Load and this caused exception still do not know why, now that i replace parse with load everything is fine, your post saved me lots of debugging time cheers. When working with niem xml the essential thing to remember is that the only thing that ever really changes is the name of the tag and sometimes the namespace. Notice that descendants is recursive in the sense that it returns all of the child nodes of the first node specified, then the child nodes of each of those and so on. I want to query for elements with a particular name at any depth using linq. Microsoft has definitely put a lot of time into thinking out the system. Galileo computing, galileo computing professionelle bucher. Descendants sintal looks for the first sintal tag in the document, not the parent node you previously selected. In second snippet, the linq query is used where xdocument loads an xml document to memory then an extension method descendants is called which returns the root node of xml to a query. The xdocument class derives from xcontainer and therefore inherits the members of xcontainer, xnode, and xobject. Heres a simple example of selecting the last n elements of a xml document using linq to xml. Linq is from the linq to xml api and xmldocumentsystem. A sitemap contains a list of all pages and in some cases images. Reverse which inverts the order of the elements in a sequence, and use take2 to return 2 elements, as shown in the following code. The xdocument class represents an xml document that can contain a dtd, one root xml element, zerotomany xml comments, and zerotomany xml processing instructions.

The following code shows how to get descendants elements with where clause. Youll notice that the output above returns the first book that is under the books. When you serialize the package using the savetobase64 or savetoflatopc functions, the modified xdocument will be serialized as well. To solve this problem in ie, set the selectionlanguage to xpath. Here in this article, i am going to show you, with small examples, on how to. Writelinexelement in the previous code, in the first statement, i generate a. Therefore, the first book in the library may fall under category computers and. Read xhtml into xdocument html can be wellformed xml xhtml 1. Using linq to xml and handling namespaces lichtenbytes. Linq to xml is a builtin linq data provider that is implemented within the system. Why not create a book class with author and title properties, then. This article is the part ii of the 3part linq to xml series. If not, you can start off with linq to xml by checking some tutorials at getting ready for. This first example loads a sitemap xml file from a website.

Notice that descendants is recursive in the sense that it returns all of the child nodes of the first node specified. You can use the descendants axis method to quickly write code to find a single uniquely named element. The order in which the child nodes are returned is described as document order, i. Finally, select keyword is used which specify the returned elements in this case all the root node elements. Linq provides necessary classes, methods and properties to read and update xml documents too. The reason you are getting the sintal element from the first groof tag is that doc.

I have two button controls on my web page to do the next and previous operations on the xml doc. The example im giving below is more efficient, but may be too complex for the task you require small files. Why or when you should shouldnt use descendants method. I hope you have read the previous article some common operations using linq to xml part i. To load the xml document in an object, i am using the xdocument class. In addition, ill store the bookname value in a viewstate, so i can use it later to. Searched on the internet for days but found nothing, think the problem is everyone is using vs and am hand coding so not sure what name spaces. Option explicit on partial class site inherits system. This book viewer offers an interface for viewing a set of images of a book s pages. In order to select the last two elements, use the ienumerable. I used the value property on attribute, which is what to do if the attribute must appear on a given element. Basically descendants recurses, whereas elements only gets direct children. As microsoft says, linq to xml provides a clean programming model that enables you to read, construct and write xml data.

Whats the best way to grab only the direct descendants of. For the first example, lets say that we want to get a list of book titles that have xml in the title. Mar 09, 2008 this is part one of a multipart post where i will show some of the techniques weve been using to parse niem xml documents using linq. Descendants is used to returns the collection of descendant element for the book and title. The powerful idioms that you can use in linq to xml make tough xml. Declaration is null, the output will have an xml declaration if the writer has writer. Or is there some builtin method im missing that can get this for me. Annotation generic and nongeneric methods that return the first annotation of. Sep 11, 2016 read or parse xml using xdocument linq 9.

How to find a single descendant using the descendants. This technique is especially useful when you want to find a particular descendant with a specific name. Only elements that have a matching xname are included in the collection. Sample code to retrieve element values using linq xml. For instance, if an element must appear, use first instead of firstordefault. Knoten person des gefundenen elements referenzieren var elemts person. Xelement, xattribute, xnamespace, xdirective, and more.

The variable xdocer is the results of the linq query which returns a collection of xelement s that were sorted. Working with inmemory open xml documents eric whites blog. We will see how we can use the descendants method in our example to target a. In ie 5,6,7,8,9 first node is0, but according to w3c, it is 1. You load the whole document into memory the xdocument and then aggregate all the output into memory before writing it to a file. Linq or language integrated query, as you know is set of features introduced first with. Gets the root element of the xml tree for this document. The xdocument class contains the information necessary for a valid xml document. Get namespaces from an xml document with xpathdocument. Converting xdocument to xmldocument and vice versa. To use these classes, you must add a reference to the system. Should i write a linq query that selects elements where parent. In the quest to design a way to use linq over xml data, microsoft needed to create a new set of classes that would simplify the task, so it created the xdocument classes. Get descendants elements with where clause in csharp description.

One of the most fantastic benefits of linq to xml is the expressive way that you can write code to create and transform xml. This is a class for reading wellformed xhtml with or without a doctype into a. The buttons click event will call the code behind procedures to execute the navigation. This example uses the first standard query operator. The class has many useful methods, and one of it is the load method. The xmldocument class was the first way to handle reading and writing xml using the.

When you serialize an xdocument, even if xdocument. You could write the code to navigate to the desired element, but it is often faster and easier to write the code using the descendants axis. Youre probably saving down as a different encoding to the original document, and different from what the target application is expecting. In the following example i will load the xml then enumerate over the child nodes, to extract specific values and then display them.

Elementcommand, i get the first command element, and that makes sense. The primary difference between both the classes is that an xdocument can contain xml declaration, xml document type dtd and processing instructions. I am loading the xml directly, but you can load it from other locations using the load option of xdocument. How to get first level of children by linq stack overflow. These store both the namespace and the local element name. The xelement class represents an xml element with a name. This is accomplished with one of the following code snippets of course there are numerous ways to do this, ill cover two. How to find a single descendant using the descendants method c.

Here is the xml file created in the previous lesson. Descendants returns a collection of the descendant elements for this document or element, in document order. This returns all of the child nodes below the name xelement in the tree, i. Xmldocument is the standard domstyle api for xml if youre using.

Returns a filtered collection of the descendant elements for this document or element, in document order. Both the classes contain the load method which accepts a file, a url or xmlreader and allows xml to be loaded. Descendants xname returns a filtered collection of the descendant elements for this document or element, in document order. How to read xml files in windows 8 winrt geekchamp. Query an xml document using linq to xml intertech blog. This includes an xml declaration, processing instructions, and. The first step in querying the file is getting it into memory as an xdocument object.

Now, if author was more complex element, you can create an author. Mar 17, 2010 for those of you who have been around the computer industry for a while, my claimtofame is that i was the author of the norton commander, which did very well. Now that the file is in memory in our xdocument object, we are ready to query against it. The code sample is provided as one of the many ways you can implement to read an xml file and specific element values based on element name or attribute.

First we load the xml into an xdocument and ask for the attributes hanging off the root, but we just want namespace declarations. We will use mostly xdocument and xmldocument class to manipulate. How to find a single descendant using the descendants method. Using linq to read, add, edit, and delete xml elements. In the previous post, you learned how to create an xml file from a collection of book objects with linq. Now, you will learn how to read, add, edit, and delete elements of the xml file that is stored in your computer. You can rate examples to help us improve the quality of examples. Splitting runs in open xml word processing document paragraphs.

There are an opening element and closing element as well, which are. Returns a collection of the descendant elements for this document or element, in document. I name the reference to the root element simply root, like so. I parse this into an xdocument, then i get a reference to the root property of that xdocument.