extract id attributes strings

Question

I am trying to extract all id attributes (as List) where the string starts with ###. This is my first attempt:

const string xml = @"<?xml version=""1.0"" encoding=""utf-8"" ?>
            <Actions>
            <Action id=""###SignIn"">1</Action>
            <Action id=""SignOut"">2</Action>
            <Action id=""###Open"">3</Action>
            </Actions>";

var xdoc = XDocument.Parse(xml);
var test = xdoc.Root.Elements()
.Where(e => e.Attribute("id").Value.StartsWith("###"))
.Select(e => e.Attribute("id").Value.StartsWith("###")).ToList();

Ultimately, I would like to replace those string with values in a dictionary (the key values are the same as the strings found in the xm data).

Answer 1

A slight modification to the Select() part of your attempt should do :

var xdoc = XDocument.Parse(xml);
var test = xdoc.Root
               .Elements()
               .Where(e => e.Attribute("id").Value.StartsWith("###"))
               .Select(e => e.Attribute("id")).ToList();

foreach (var t in test)
{
    //replace id attribute value with string from dictionary
    t.Value = myDictionary[t.Value];
}