ASP.NET中XML转JSON的方法

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  <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
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();
}