detecting missing XML elements (C#)

[Shurik12]

Hello,

 

I'd like to read in a XML file elements' content into a number of arrays

 

(if it makes any difference: I'm using PL-SQL associative arrays to make

a "bulk" insert of the XML file into an Oracle table)

 

//"load" the xml file 
XmlTextReader textReader = New XmlTextReader(path);
textReader.Read();
XmlDocument doc = New XmlDocument();
doc.Load(textReader);

// Get all elements here
XmlNodeList gridid = doc.GetElementsByTagName("gridid");
XmlNodeList spread6m = doc.GetElementsByTagName("Spread6m");
.... other elements go here



// Loop throught the whole document And populate the arrays (declared And instantiated alerady)
For (int i = 0; i < CountElements; i++)  

{
GridIDArray[i] = System.Convert.ToInt32(gridid[i].InnerXml);
Spread6mArray[i] = System.Convert.ToString(spread6m[i].InnerXml);   
}
...

 

 

Since 'spread6m' element is not present in each of the root elements (see the attachment for a screenshoot), application throws "Object reference not set to an instance of an object."

 

 

I've tried something similar too

 

// Get a XML node Type object.
Type XmlNodeType = TypeOf(XmlNode);

 If (XmlNodeType.IsInstanceOfType(spread6m[i]))

               {
                       Spread6mArray[i] = System.Convert.ToString(spread6m[i].InnerXml);
               }
                   Else
               
               {
                       Spread6mArray[i] = 0;
               }

 

 

but it did not really seem to help

 

 

So the question is: how can I detect that an element is missing within the current root element and populate the array's item with 0 accordingly?

 

Thanks,

Shurik.

[MrPaul]

Avoid GetElementByTagName

 

I think you need to try a different approach. Your current method makes it impossible to know which rows are missing a Spread6m element, since the GetElementByTagName places all elements in an array regardless of their position in the document, making it not obvious which row they are children of.

 

I would recommend you loop through the row elements one at a time and process each individually.

 

            XmlNodeList rows;
           XmlNode     node;

           //Select rows
           rows = doc.SelectNodes("row");
           
           //Initialize arrays
           gridIDArray = new int[rows.Count];
           spread6mArray = new string[rows.Count];

           for (int i = 0; i < rows.Count; i++) {
               //Process row

               //Get GridID
               node = rows[i].SelectSingleNode("GridID");
               gridIDArray[i] = (node == null) ? 0 : int.Parse(node.InnerText);

               //Get Spread6m
               node = rows[i].SelectSingleNode("Spread6m");
               spread6mArray[i] = (node == null) ? "0" : node.InnerText;

               //etc
           }

 

There are of course other methods you can use, such as creating an XSD and using it to instantiate a graph of objects with specified default values.

 

Also, you can mark up C# code with [cs][/cs].

 

Good luck :cool:

[Shurik12]

Hi,

 

Thanks for the response.

You're absoultely right, the is the approach to take.

 

Thanks for the help

 

Shurik.

 

p.s the hint about the tags is taken.