source: Common/XmlExt.cs

using System;
using System.Globalization;
using System.Xml;

namespace Common
{
    public static class XmlNodeExt
    {
        public static bool GetValueBool(this XmlNode xmlNode, string name, bool defaultValue)
        {
            XmlNode node2 = xmlNode.SelectSingleNode(name);
            if (node2 != null)
            {
                if (node2.InnerText.ToLowerInvariant() == "true") return true;
                return false;
            }
            return defaultValue;
        }

        public static string GetValueString(this XmlNode xmlNode, string name, string defaultValue)
        {
            XmlNode node2 = xmlNode.SelectSingleNode(name);
            if (node2 != null)
            {
                return node2.InnerText;
            }
            return defaultValue;
        }

        public static int GetValueInt(this XmlNode xmlNode, string name, int defaultValue)
        {
            XmlNode node2 = xmlNode.SelectSingleNode(name);
            if (node2 != null)
            {
                if (int.TryParse(node2.InnerText, out int value))
                {
                    return value;
                }
                return defaultValue;
            }
            return defaultValue;
        }

        public static long GetValueLong(this XmlNode xmlNode, string name, long defaultValue)
        {
            XmlNode node2 = xmlNode.SelectSingleNode(name);
            if (node2 != null)
            {
                if (long.TryParse(node2.InnerText, out long value))
                {
                    return value;
                }
                return defaultValue;
            }
            return defaultValue;
        }

        public static float GetValueFloat(this XmlNode xmlNode, string name, float defaultValue)
        {
            XmlNode node2 = xmlNode.SelectSingleNode(name);
            if (node2 != null)
            {
                if (float.TryParse(node2.InnerText, out float value))
                {
                    return value;
                }
                return defaultValue;
            }
            return defaultValue;
        }

        public static double GetValueDouble(this XmlNode xmlNode, string name, double defaultValue)
        {
            XmlNode node2 = xmlNode.SelectSingleNode(name);
            if (node2 != null)
            {
                if (double.TryParse(node2.InnerText, out double value))
                {
                    return value;
                }
                return defaultValue;
            }
            return defaultValue;
        }

        public static TimeSpan GetValueTimeSpan(this XmlNode xmlNode, string name, TimeSpan defaultValue)
        {
            XmlNode node2 = xmlNode.SelectSingleNode(name);
            if (node2 != null)
            {
                return XmlConvert.ToTimeSpan(node2.InnerText);
            }
            return defaultValue;
        }

        public static DateTime GetValueDateTime(this XmlNode xmlNode, string name, DateTime defaultValue)
        {
            XmlNode node2 = xmlNode.SelectSingleNode(name);
            if (node2 != null)
            {
                return XmlConvert.ToDateTime(node2.InnerText, XmlDateTimeSerializationMode.RoundtripKind);
            }
            return defaultValue;
        }

        public static void SetValueBool(this XmlNode xmlNode, string name, bool value)
        {
            if (xmlNode.OwnerDocument != null)
                xmlNode.AppendChild(xmlNode.OwnerDocument.CreateElement(name)).InnerText = value.ToString();
        }

        public static void SetValueString(this XmlNode xmlNode, string name, string value)
        {
            if (xmlNode.OwnerDocument != null && !string.IsNullOrEmpty(value))
                xmlNode.AppendChild(xmlNode.OwnerDocument.CreateElement(name)).InnerText = value;
        }

        public static void SetValueInt(this XmlNode xmlNode, string name, int value)
        {
            if (xmlNode.OwnerDocument != null)
                xmlNode.AppendChild(xmlNode.OwnerDocument.CreateElement(name)).InnerText = value.ToString();
        }

        public static void SetValueLong(this XmlNode xmlNode, string name, long value)
        {
            if (xmlNode.OwnerDocument != null)
                xmlNode.AppendChild(xmlNode.OwnerDocument.CreateElement(name)).InnerText = value.ToString();
        }

        public static void SetValueFloat(this XmlNode xmlNode, string name, float value)
        {
            if (xmlNode.OwnerDocument != null)
                xmlNode.AppendChild(xmlNode.OwnerDocument.CreateElement(name)).InnerText = value.ToString(CultureInfo.InvariantCulture);
        }

        public static void SetValueDouble(this XmlNode xmlNode, string name, double value)
        {
            if (xmlNode.OwnerDocument != null)
                xmlNode.AppendChild(xmlNode.OwnerDocument.CreateElement(name)).InnerText = value.ToString(CultureInfo.InvariantCulture);
        }

        public static void SetValueTimeSpan(this XmlNode xmlNode, string name, TimeSpan value)
        {
            if (xmlNode.OwnerDocument != null && value != TimeSpan.Zero)
                xmlNode.AppendChild(xmlNode.OwnerDocument.CreateElement(name)).InnerText = XmlConvert.ToString(value);
        }

        public static void SetValueDateTime(this XmlNode xmlNode, string name, DateTime value)
        {
            if (xmlNode.OwnerDocument != null && value != DateTime.MinValue)
                xmlNode.AppendChild(xmlNode.OwnerDocument.CreateElement(name)).InnerText = XmlConvert.ToString(value, XmlDateTimeSerializationMode.RoundtripKind);
        }
    }
}