使用C＃中的另一个XML文档中的元素附加XML文档

Question

I am trying to build an automatic test grading application and I want the end result to be a savefiledialog prompt that allows the grader to save a new xml file to any location.

The trick is I need that output xml to include the original test + appended answers from answer key + final grade. Here is what I have so far but Im getting an error. I am not familiar with .appendchild() so Im thinking that is where my issue lies.

    private void cbOutput_Click(object sender, EventArgs e)
    {
        XmlNode rootTest = xmlAnswers.DocumentElement;
        XmlNode rootKey = xmlAnswerKey.DocumentElement;

        XmlNodeList nodeListTest = rootTest.SelectNodes("//answer");

        foreach (XmlNode item in nodeListTest)
        {
            XmlNode importNode = rootTest.OwnerDocument.ImportNode(rootKey, true);

            item.AppendChild(importNode);
        }

        SaveFileDialog savefiledialog1 = new SaveFileDialog();
        saveFileDialog1.Filter = "XML Files|*.XML";
        saveFileDialog1.Title = "Choose Location to Save Graded Test";

        if (saveFileDialog1.ShowDialog() == DialogResult.OK)
        {
            if (!string.IsNullOrEmpty(savefiledialog1.FileName))
            using (Stream s = File.Open(savefiledialog1.FileName, FileMode.Create))
            using (StreamWriter sw = new StreamWriter(s))
            {
                sw.Write(rootTest + tbTotal.Text);
            }
        }

Answer 1

I have a hard time following your code, since it is pre .Net 3.5 XML code. I started in on C# when 3.5 came out. Seems like you are adding the keys to every answer in the test? Doesn't make sense from what you wrote as your description. But if that was your goal, you can try this.

If you can use .Net 3.5 then use XElement / XDocument , using these converters do

XElement test = xmlAnswers.ToXElement();
XElement keys = xmlAnswerKey.ToXElement();

test.Descendants("answer")
    .ToList()
    .ForEach(a => a.Add(new XElement(keys))); // Add clone of keys to each answer
// Dialog stuff
test.Save(savefiledialog1.FileName);

Or, using your description (I'll have to try and make up what you should be doing, since your XML is hidden from us).

XElement test = xmlAnswers.ToXElement();
XElement keys = xmlAnswerKey.ToXElement();

test.Add(keys.Descendants("answer").ToList()); // Add Answers to test
test.Add(new XElement("finalgrade", "A")); // Add final grade
// Dialog stuff
test.Save(savefiledialog1.FileName);

PS, don't do all the converting, adding of answers etc outside the

if (saveFileDialog1.ShowDialog() == DialogResult.OK)

Otherwise, if it isn't OK then you are wasting the time of your user.