Getting Data from Huge xml files without Loading into memory. c#

Question

I have an xml with the following pattern.

<root>
 <Main1>
   .
   .
   .
 <Main1/>
 <Main2>
   <Main2ChildNode Id="1">Very Very Huge Base 64 String<Main2ChildNode>
   <Main2ChildNode Id="2">Very Very Huge Base 64 String<Main2ChildNode>
    .
    .
    .
   <Main2ChildNode Id="n">Very Very Huge Base 64 String<Main2ChildNode>
 <Main2/>
</root>

Instead of loading the xml into memory I am trying to access the inner text of each Main2ChildNode based on the Id Property. I need to collect entire data under Main2 section and process further in this way one by one. The below code which I am trying is iterating over the entire xml line by line.

Is there any better way to identify a specific Main2ChildNode 's inner text with good performance.

 private String GetImageData(String Main2ChildNodeId,String XmlFilePath)
    {
         string data=null;
         using (XmlReader reader = XmlReader.Create(XmlFilePath))
         {
             reader.MoveToContent();
             while (reader.Read() && data == null)
             {
                 switch (reader.NodeType)
                 {
                     case XmlNodeType.Element:
                         if (reader.Name == "Main2ChildNode")
                         {
                             XElement el = XElement.ReadFrom(reader) as XElement;
                             if ((String)el.Attribute("Id") == Main2ChildNodeId)
                             {
                                 data= el.Value;
                             }
                         }
                         break;
                 }
             }
         }
         return data
    }

Please suggest a better solution.

Answer 1

Try Using SAX with is event based, ie event is triggered while parsing, rather than reading whole document at once. It helps to load XML in partition.