向现有xml的元素添加属性

Question

This is my code:

var nodes = XDocument.Parse(gridxml).Root.Elements();
                    var attribute = new XAttribute("open", "0");
                    foreach (var node in nodes)
                    {
                        node.Add(attribute);
                    }

When I check the value of the nodes in debug mode, I see that all of them have the open attribute. However, when I check the value of gridxml, the elements don't have the open attribute. What am I doing wrong?

Answer 1

gridxml in you example is a String which you are never modifying. XDocument is not an XML-friendly String wrapper, it is a separate object, which has no influence over the String it was initialized from.

You should be checking xdoc.ToString() instead of gridxml . If for some reason you need to have the updated contents in your original variable, do gridxml = xdoc.ToString() after adding the attributes.

Answer 2

You are adding attributes to copies of the nodes, try this:

        string gridxml = "<node1><node2></node2><node3></node3></node1>";

        var xdoc = XDocument.Parse(gridxml);
        var attribute = new XAttribute("open", "0");

        foreach (var node in xdoc.Root.Elements())
        {
            node.Add(attribute);
        }

        Console.WriteLine(xdoc.ToString());