How can I convert this InstallScipt code to C#?

Question

I'm converting my InstallScript Custom Actions To Managed Custom Actions using the DTF (Microsoft Deployment Foundation) Namespace. There is a piece of InstallScript code that I'm having trouble with converting to C# where I need to do some XML File manipulation. The original InstallScript Code is below. My code below it is how I've converted it so far. Is there a better way of converting it so that I can take advantage of the dot notation (Intellisense) instead of having the XML document object latebound.

    set oDoc = CoCreateObject("Microsoft.XMLDOM");
    if (IsObject(oDoc)) then
        oDoc.async = FALSE;
        oDoc.validateOnParse = FALSE;
        oDoc.resolveExternals = FALSE;
        oDoc.preserveWhiteSpace = VARIANT_TRUE;

        oDoc.load(szCryptomaticConfigFile);

        szXPath = CRYPTOMATIC_SETTINGS_PATH;
        set oSettingsNode = oDoc.selectSingleNode(szXPath);

        szValue = CRYPTOMATIC_SETTINGS_VALUE;
        oSettingsNode.nodeTypedValue = szValue;

        oDoc.Save(szCryptomaticConfigFile);
   endif;

My Conversion

        dynamic oXMLDOMDoc = Activator.CreateInstance(Type.GetTypeFromProgID("Microsoft.XMLDOM"));
        if (oXMLDOMDoc != null)
        {
            oXMLDOMDoc.async = false;
            oXMLDOMDoc.validateOnParse = false;
            oXMLDOMDoc.preserveWhiteSpace = VARIANT_TRUE;
            oXMLDOMDoc.load(szCryptomaticConfigFile);

            string szXPath = CRYPTOMATIC_SETTINGS_PATH;
            dynamic oSettingsNode = oXMLDOMDoc.selectSingleNode(szXPath);

            string szXValue = CRYPTOMATIC_SETTINGS_VALUE;
            oSettingsNode.nodeTypedValue = szXValue;

            oXMLDOMDoc.Save(szCryptomaticConfigFile);
            return ActionResult.Success;
        }
        else
        {
            return ActionResult.Failure;
        }

Answer 1

Yes, this is simply opening an XmlDocument, finding a specific node and updating its value before saving the file again.

The code is along the lines of (untested, typed from memory)

var xml = new XmlDocument();
xml.Load(szCryptomaticConfigFile);
var node = xml.SelectSingleNode(szXPath);
node.Value = CRYPTOMATIC_SETTINGS_VALUE
xml.Save(szCryptomaticConfigFile);