Put a breakpoint on one line and the program works. Move the breakpoint to the next line and it crashes

Question

I have this code:

XmlDocument doc = new XmlDocument();
doc.Load("file.xml");

XmlNodeList nodes = doc.SelectNodes("//myElement");  // Line 4

for (int i = 0; i < 5; i++) // Line 6
{
    nodes[i].ParentNode.RemoveChild(nodes[i]);
}

doc.Save("output.xml");

If I put a breakpoint on line 4 the program works just fine. However, if I put a breakpoint on any line past that (such as 6), I get the object reference not set to instance of object error because nodes only has one item in it.

The program crashes every time I run it without breakpoints. If I put a breakpoint on line 4 though, nodes has the proper count of 85 and everything works perfectly.

Even If I do Thread.Sleep(10000) before and after line 4, the program still crashes because it only finds 1 node.

Does anyone know why this is?

Answer 1

Changed the code to this and now it works flawlessly, breakpoints or not, 100% of the time:

XDocument doc = XDocument.Load("file.xml");

List<XElement> nodes = doc.Descendants("myElement").ToList();

for (int i = 0; i < 5; i++)
{
    nodes[i].Remove();
}

doc.Save("output.xml");

Not sure why SelectNodes was giving me trouble but this solution seems to fix everything.