Convert XML to JSON using C#

Here is the working solution I borrowed and modified from somewhere. But I forgot the original source. If you're the original author, please let me know if you'd like your name listed on this post.

 
public static class JSon
{
    public static string XmlToJSON(string xml)
    {
        XmlDocument doc = new XmlDocument();
        doc.LoadXml(xml);

        return XmlToJSON(doc);
    }
    public static string XmlToJSON(XmlDocument xmlDoc)
    {
        StringBuilder sbJSON = new StringBuilder();
        sbJSON.Append("{ ");
        XmlToJSONnode(sbJSON, xmlDoc.DocumentElement, true);
        sbJSON.Append("}");
        return sbJSON.ToString();
    }

    //  XmlToJSONnode:  Output an XmlElement, possibly as part of a higher array
    private static void XmlToJSONnode(StringBuilder sbJSON, XmlElement node, bool showNodeName)
    {
        if (showNodeName)
            sbJSON.Append("\"" + SafeJSON(node.Name) + "\": ");
        sbJSON.Append("{");
        // Build a sorted list of key-value pairs
        //  where   key is case-sensitive nodeName
        //          value is an ArrayList of string or XmlElement
        //  so that we know whether the nodeName is an array or not.
        SortedList<string, object> childNodeNames = new SortedList<string, object>();

        //  Add in all node attributes
        if (node.Attributes != null)
            foreach (XmlAttribute attr in node.Attributes)
                StoreChildNode(childNodeNames, attr.Name, attr.InnerText);

        //  Add in all nodes
        foreach (XmlNode cnode in node.ChildNodes)
        {
            if (cnode is XmlText)
                StoreChildNode(childNodeNames, "value", cnode.InnerText);
            else if (cnode is XmlElement)
                StoreChildNode(childNodeNames, cnode.Name, cnode);
        }

        // Now output all stored info
        foreach (string childname in childNodeNames.Keys)
        {
            List<object> alChild = (List<object>)childNodeNames[childname];
            if (alChild.Count == 1)
                OutputNode(childname, alChild[0], sbJSON, true);
            else
            {
                sbJSON.Append(" \"" + SafeJSON(childname) + "\": [ ");
                foreach (object Child in alChild)
                    OutputNode(childname, Child, sbJSON, false);
                sbJSON.Remove(sbJSON.Length - 2, 2);
                sbJSON.Append(" ], ");
            }
        }
        sbJSON.Remove(sbJSON.Length - 2, 2);
        sbJSON.Append(" }");
    }

    //  StoreChildNode: Store data associated with each nodeName
    //                  so that we know whether the nodeName is an array or not.
    private static void StoreChildNode(SortedList<string, object> childNodeNames, string nodeName, object nodeValue)
    {
        // Pre-process contraction of XmlElement-s
        if (nodeValue is XmlElement)
        {
            // Convert  <aa></aa> into "aa":null
            //          <aa>xx</aa> into "aa":"xx"
            XmlNode cnode = (XmlNode)nodeValue;
            if (cnode.Attributes.Count == 0)
            {
                XmlNodeList children = cnode.ChildNodes;
                if (children.Count == 0)
                    nodeValue = null;
                else if (children.Count == 1 && (children[0] is XmlText))
                    nodeValue = ((XmlText)(children[0])).InnerText;
            }
        }
        // Add nodeValue to ArrayList associated with each nodeName
        // If nodeName doesn't exist then add it
        List<object> ValuesAL;

        if (childNodeNames.ContainsKey(nodeName))
        {
            ValuesAL = (List<object>)childNodeNames[nodeName];
        }
        else
        {
            ValuesAL = new List<object>();
            childNodeNames[nodeName] = ValuesAL;
        }
        ValuesAL.Add(nodeValue);
    }

    private static void OutputNode(string childname, object alChild, StringBuilder sbJSON, bool showNodeName)
    {
        if (alChild == null)
        {
            if (showNodeName)
                sbJSON.Append("\"" + SafeJSON(childname) + "\": ");
            sbJSON.Append("null");
        }
        else if (alChild is string)
        {
            if (showNodeName)
                sbJSON.Append("\"" + SafeJSON(childname) + "\": ");
            string sChild = (string)alChild;
            sChild = sChild.Trim();
            sbJSON.Append("\"" + SafeJSON(sChild) + "\"");
        }
        else
            XmlToJSONnode(sbJSON, (XmlElement)alChild, showNodeName);
        sbJSON.Append(", ");
    }

    // Make a string safe for JSON
    private static string SafeJSON(string sIn)
    {
        StringBuilder sbOut = new StringBuilder(sIn.Length);
        foreach (char ch in sIn)
        {
            if (Char.IsControl(ch) || ch == '\'')
            {
                int ich = (int)ch;
                sbOut.Append(@"\u" + ich.ToString("x4"));
                continue;
            }
            else if (ch == '\"' || ch == '\\' || ch == '/')
            {
                sbOut.Append('\\');
            }
            sbOut.Append(ch);
        }
        return sbOut.ToString();
    }
}
 

To convert a given XML string to JSON, simply call XmlToJSON() function as below.

 
 
string xml = "<menu id=\"file\" value=\"File\"> " +
                  "<popup>" +
                    "<menuitem value=\"New\" onclick=\"CreateNewDoc()\" />" +
                    "<menuitem value=\"Open\" onclick=\"OpenDoc()\" />" +
                    "<menuitem value=\"Close\" onclick=\"CloseDoc()\" />" +
                  "</popup>" +
                "</menu>";

    string json = JSON.XmlToJSON(xml);
    // json = { "menu": {"id": "file", "popup": { "menuitem": [ {"onclick": "CreateNewDoc()", "value": "New" }, {"onclick": "OpenDoc()", "value": "Open" }, {"onclick": "CloseDoc()", "value": "Close" } ] }, "value": "File" }}