Xmldocument from file c#

Microsoft makes no warranties, express or implied, with respect to the information provided here. There is a load or parse error in the XML. In this case, a FileNotFoundException is raised. The Load method always preserves significant white space. The PreserveWhitespace property determines whether or not insignificant white space, that is white space in element content, is preserved.

The default is false ; white space in element content is not preserved. If you want validation to occur, you can create a validating XmlReader instance by using the XmlReaderSettings class and the Create method.

For more information, see the Remarks section of the XmlReader reference page. If your application needs to know which encoding is used to read the stream, consider using an XmlTextReader object to read the stream, and then use the XmlTextReader. Encoding property to determine the encoding. The most popular way to do this is refer to a file on your local computer or on a network. This example loads XML from a file. If the file doesn't exist, it just generates some XML and loads that.

Start with an XML schema like this one. This schema defines the data types in the XML and which attributes are required. Create an event handler that executes when code attempts to modify your XML file in ways that violate the rules of the schema. You can use properties to navigate around an XML document. But before you use any of them, let's quickly review a few terms. Your document is composed of nodes. Each node has as single parent node directly above it. The only node that does not have a parent node is the document root, as it is the top-level node.

Most nodes can have child nodes, which are nodes directly below them. Nodes that are at the same level are siblings. The following examples show you how to obtain the root node, jump to the first child node of the root node, access any of its child nodes, get back out to the parent node, and then navigate across sibling nodes.

This example gets the root node and then uses that node to output the contents of the document to the console. This example jumps to the first child node of the root node and then iterates through the child nodes of that node if any exist. Use the ParentNode property. This example writes the price of a book to the console. The price node is the last child of a book node. The most popular way to find one or more nodes of data is to use an XPath query string, but there are also methods that don't require one.

The string used in this example is an Xpath query. You can find more examples of them here: XPath examples. You can also use the GetElementById to retrieve nodes. To use this approach, you'll have to define ID's in the document type definition declarations of your XML file. After you get a node, you get the value of attributes or child nodes. This example does that with a book node. This example selects all books where the author's last name is Austen , and then changes the price of those books.

You can also get a collection of nodes by using the name of the node. For example, this example gets a collection of all book titles.

To add a node, use the CreateElement method or the CreateNode method. To add a data node such as a book, use the CreateElement method. This example creates a book node, adds attributes to that node, and then adds that node to the document. To remove a node, use the RemoveChild method.

This example removes a book from the document and any whitespace that appears just before the book node. You can choose where you want a node to appear in your document by using the InsertBefore and InsertAfter methods. This example shows two helper methods. One of them moves a node higher in a list. The other one moves a node lower. These methods could be used in an application that enables users to move books up and down in a list of books.

When a user chooses a book and presses an up or down button, your code could call methods like these to position the corresponding book node before or after other book nodes. Initializes a new instance of the XmlDocument class. Initializes a new instance of the XmlDocument class with the specified XmlImplementation. Gets an XmlAttributeCollection containing the attributes of this node.

Gets the root XmlElement for the document. Gets the XmlImplementation object for the current document. Throws an InvalidOperationException in all cases. Gets the first child element with the specified Name. Gets the XmlNameTable associated with this implementation. If the specified file exists, this method overwrites it. The operation would not result in a well formed XML document for example, no document element or duplicate XML declarations.

White space is preserved only if PreserveWhitespace is set to true. The XmlDeclaration of the current XmlDocument object determines the encoding attribute in the saved document. The value of the encoding attribute is taken from the XmlDeclaration. Encoding property. If the XmlDocument does not have an XmlDeclaration, or if the XmlDeclaration does not have an encoding attribute, the saved document will not have one either.

For example, the following C code. Note that only the Save method enforces a well-formed XML document. All other Save overloads only guarantee a well-formed fragment. Its text is set with InnerText property. The XmlDeclaration is appended to the document with AppendChild.

The declaration tag is the first tag in the document. We go through the dictionary and create necessary elements and an attribute for each user object. The XmlNode. ChildNodes returns all the children of the given node. The property returns the XmlNodeList , which represents an ordered collection of nodes.

The XmlNodeList. Count property gets the number of nodes in the XmlNodeList.