XML转JSON代码如下：

private 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 childNodeNames = new SortedList(); 
 
    //  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) 
    { 
        ArrayList alChild = (ArrayList)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 childNodeNames, string nodeName, object nodeValue) 
{ 
    // Pre-process contraction of XmlElement-s 
    if (nodeValue is XmlElement) 
    { 
        // Convert  into "aa":null 
        //          xx 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 
    object oValuesAL = childNodeNames[nodeName]; 
    ArrayList ValuesAL; 
    if (oValuesAL == null) 
    { 
        ValuesAL = new ArrayList(); 
        childNodeNames[nodeName] = ValuesAL; 
    } 
    else 
        ValuesAL = (ArrayList)oValuesAL; 
    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(); 
}