Best Method of standard string to XML legal string C#

Currently my understanding of XML legal strings is that all is required is that you convert any instances of: &, ", ', <, > with & " ' < > So I made the following parser:

private static string ToXmlCompliantStr(string uriStr)
{
    string uriXml = uriStr;
    uriXml = uriXml.Replace("&", "&amp;");
    uriXml = uriXml.Replace("\"", "&quot;");
    uriXml = uriXml.Replace("'", "&apos;");
    uriXml = uriXml.Replace("<", "&lt;");
    uriXml = uriXml.Replace(">", "&gt;");
    return uriXml;
}

I am aware that there are similar questions out there with good answers (which is how I was able to write this function) I am writing this question to ask if this code will translate ANY string that C# can throw at it and have XDocument parse it as a part of a whole document without any complaints as all the questions out there that I've found state that these are the only escape characters, not that parsing them will cause 100% valid XML string. I've gone as far as reading through the decompiled XNode class trying to see how that parse it.

Thanks

Jon Skeet
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Firstly, you should absolutely not do this yourself. Use an XML API - that way you can trust that to do the right thing, rather than worrying about covering corner cases etc. You generally shouldn't be trying to come up with an "escaped string" at all - you should pass the string to the XElement constructor (or XAttribute, or whatever your situation is).

In other words, I think you should try really hard to design your application so that you don't need a method of the kind you've shown in your question at all. Look at where you'd be using that method, and see whether you can just create an XElement (or whatever) instead. If you try to treat XML as a data structure in itself rather than just as text, you'll have a much better experience in my experience.

Secondly, you need to understand that in XML 1.0 at least, there are Unicode characters that cannot be validly represented in XML, no matter how much escaping you use. In particular, values U+0000 to U+001F are unrepresentable other than U+0009 (tab), U+000A (line feed) and U+000D (carriage return). Also if you have a string which contains invalid UTF-16 (e.g. an unmatched half of a surrogate pair), that can't be correctly represented in XML.

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