Reading adjacent elements in XML

Question

I've got a large XML file and so I'm using XMLTextReader. I'm having trouble reading the value becaues the formatting is a bit different from other XML files I've worked with.

<class>
   <column>Size</column><int>30</int>
   <column>TeamColor</column><string>red</string>
   ...
</class>

How can I read Size and then get the value 30? I've currently got

while (reader.Read())
{
     if (reader.NodeType == XmlNodeType.Element)                    
         element = reader.Name;  
     else if (reader.NodeType == XmlNodeType.Text)
     {
         if (element == "column")
         {
             if(reader.Value == "Size")
             //can get true here, but can't return the int value next to it
         }
     }
}

score 0 · Answer 1 · answered Nov 06 '12 at 02:58

If you can use xpath, from the <column> context node try (following-sibling::*)[1]. This will select the elements * along following-sibling axis (things that are peers to the context but come after in document order) and then return the first element of the sequence.

Furqan Safdar · Accepted Answer · 2012-11-06T03:29:04.503

You can get all the columns with their name and associated value in the Hashtable.

Try using this piece of code snippet:

Hashtable hashTable = new Hashtable();
int intVal;
string prevColumnName = "";

while (reader.Read())
{
    if (reader.NodeType == XmlNodeType.Element)
    {
        element = reader.Name;
    }
    else if (reader.NodeType == XmlNodeType.Text)
    {
        switch (element.ToLower())
        {
            case "column":
                prevColumnName = reader.Value;
                hashTable.Add(reader.Value, null);
                break;
            case "int":
                if (int.TryParse(reader.Value, out intVal))
                    hashTable[prevColumnName] = intVal;
                break;
            case "string":
                hashTable[prevColumnName] = reader.Value;
                break;
        }
    }
}

Usage:

int size = Convert.ToInt32(hashTable["Size"]);

score 0 · Answer 3 · answered Nov 06 '12 at 05:55

Unless you store the previous value you will need to add a skipping condition allowing you to make an extra read (for the sibling) when it hits the column element and then handle any additional reads properly at the next loop.


bool skipRead = false;
while (skipRead || reader.Read())
{
     skipRead = false;
     if (reader.NodeType == XmlNodeType.Element)                    
         element = reader.Name;  
     else if (reader.NodeType == XmlNodeType.Text)
     {
         if (element == "column")
         {
             if (Reader.Read())
             {
               if(reader.NodeType == XmlNodeType.Element && reader.Name == "Size")
               {
                   // do whatever you need to here with reader.Value. 
                   // E.g size = (int) reader.Value
                   skipRead = false;
                   continue;
               } // Additional ifs for other elements in column can go here.
               else
               {
                   skipRead = true;
                   continue;
               }
             }
             else
             {
              break;
             }
         }
     }
}

Reading adjacent elements in XML

3 Answers3