Help to review whether my XML validation code is efficient

Question

Hello everyone,

I am checking againtst whether a specific input string are valid (could be used as the value for an XML element) in XML UTF-8 encoding. My goal is to tell which string (from an input string array) is not valid according to XML UTF-8 encoding standard.

Here is my code, my current implementation is straightforward -- assemble XML file with each individual string from the input string array. I am not sure whether it is the most efficient way. From functional point of view, it works.

My working environment is .Net 3.5 + VSTS 2008 + C#.

    static void Main(string[] args)
    {
        string[] inputs = { "Hello", "World", "StackOverflow", "ServerFault", "&#DFFE" };
        XmlDocument xDoc = new XmlDocument();
        string header = "<?xml version=\"1.0\" encoding=\"utf-8\"?>";
        string formatter = "<foo>{0}</foo>";
        foreach (string item in inputs)
        {
            StringBuilder builder = new StringBuilder();
            builder.Append (header);
            builder.Append (String.Format(formatter, item));
            try
            {
                xDoc.Load(new StringReader(builder.ToString()));
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.ToString());
            }
        }
    }

thanks in advance, George

Answer 1

George, when writing tests, it's best to start with a test that demonstrates the failure case.

Will your code ever fail? I don't think so.

You should start with a test that is close to the problem that made you want to create this test. I presume you had a problem with an XML file not being properly encoded? In that case, you should create a test that proves that the bad file is bad (which you already know to be true), then generalize the test so that it can detect other bad files as being bad, and all good files as being good.

Answer 2

You could do something like this :

    public static XmlElement xmlValidationElement =
        new XmlDocument().CreateElement("validator");

    static void Main(string[] args)
    {
        string[] inputs = { "Hello", "World", "StackOverflow", "ServerFault" };
        foreach (string item in inputs)
        {
            try
            {
                xmlValidationElement.InnerXml = item;
            }
            catch (XmlException ex)
            {
                Console.WriteLine(ex.ToString());
            }
        }
    }