LINQ Advice

So I was speaking to Mendhak earlier about this and whether xPath would be better. So heres the code:

Code:

---

        private void PopulateList(String SourceType, String OutputType)
        {
            //Populate The ListOfSubRules Property using LINQ to XML
            XDocument XMLDataStore = XDocument.Load("DataStore.xml");

            var XMLSubRules = from XMLSubRule in XMLDataStore.Descendants("SubRule")
                              where (XMLSubRule.Attribute("SourceType").Value == SourceType && XMLSubRule.Attribute("OuputType").Value == OutputType)
                              select new
                              {
                                  Expression = XMLSubRule.Element("Expression").Value,
                                  OpeningElement = XMLSubRule.Element("OpeningElement").Value,
                                  ClosingElement = XMLSubRule.Element("ClosingElement").Value
                              };

            foreach (var XMLSubRule in XMLSubRules)
            {
                SubRule SubRuleItem = new SubRule(XMLSubRule.Expression,
                                                  XMLSubRule.OpeningElement,
                                                  XMLSubRule.ClosingElement);
                ListOfSubRules.Add(SubRuleItem);
            }

 

        }

---

This is the Data it is operating on:

Code:

---

<?xml version="1.0" encoding="utf-8" ?>
<Store>
  <SubRules>
   
    <SubRule SourceType="XAML" OutputType="BBCODE">
      <Name>Get Tags</Name>
      <Expression>&lt;/|&lt;|&gt;|/&gt;</Expression>
      <OpeningElement></OpeningElement>
      <ClosingElement></ClosingElement>
    </SubRule>

    <SubRule SourceType="XAML" OutputType="BBCODE">
      <Name>Get Property Values</Name>
      <Expression>=&quot;[()\[\]\w#,. =:/-{}]+&quot;</Expression>
      <OpeningElement></OpeningElement>
      <ClosingElement></ClosingElement>
    </SubRule>

    <SubRule SourceType="XAML" OutputType="BBCODE">
      <Name>Get Object Names</Name>
      <Expression>(?&lt;=&lt;/|&lt;)[\w:.]+</Expression>
      <OpeningElement></OpeningElement>
      <ClosingElement></ClosingElement>
    </SubRule>

    <SubRule SourceType="XAML" OutputType="BBCODE">
      <Name>Get Property Names</Name>
      <Expression>\b[\w:.]+(?=\=&quot;)</Expression>
      <OpeningElement></OpeningElement>
      <ClosingElement></ClosingElement>
    </SubRule>
   
   
  </SubRules>

  <FormatBoxes>
   
  </FormatBoxes>
</Store>

---

And to be honest I'm not happy with the document structure either I would like to change that!

And yes the program does know what data to expect and where (Or at least it should!)

So with the XPathNavigator you'd use something like

Code:

---

foreach(XpathNavigator subRuleNode in xmlDataStore.Select("/Store/SubRules/SubRule"))
{
SubRule subRuleItem = new SubRule(subRuleNode.SelectSingleNode("Expression").Value, subRuleNode.SelectSingleNode("OpeningElement").Value, subRuleNode.SelectSingleNode("ClosingElement").Value
ListOfSubRules.Add(subRuleItem);
}

---

My gripe with .Descendants is that it is equivalent to

Code:

---

xmlDataStore.Select("//SubRule")

---

which is equivalent to

Code:

---

myXmlDocument.SelectNodes("//SubRule")

---

which does a recursive search across node names. The // (double slash) was introduced for 'unknown' XML data, in which you knew a node existed, but didn't know the XML structure or where the node would be.

Since you mentioned that this is going to be read-only, I would use XpathNavigator over XmlDocument.

Cool, My only issue with that code is that it gets EVERY subrule item, which I do not what. Can I add a LINQ satement here to query the data more specificly?

Code:

---

SubRule subRuleItem = new SubRule(subRuleNode.SelectSingleNode("Expression").Value, subRuleNode.SelectSingleNode("OpeningElement").Value, subRuleNode.SelectSingleNode("ClosingElement").Value

---

Oh! I see, you're calling it in a function. Yeah, that's easily done too.

Code:

---

foreach(XpathNavigator subRuleNode in xmlDataStore.Select("/Store/SubRules/SubRule[@SourceType='" + theParameterPassedToThisFunction + ']"))
{
SubRule subRuleItem = new SubRule(subRuleNode.SelectSingleNode("Expression").Value, subRuleNode.SelectSingleNode("OpeningElement").Value, subRuleNode.SelectSingleNode("ClosingElement").Value
ListOfSubRules.Add(subRuleItem);
}

---

The [] square brackets is like a 'where', and the @SourceType means the @ttribute named SourceType.

Ok, I see what you doing. I must look up more XML and LINQ as im sure there is a better method than .Descendants. I will have a look at xpath too and the DataStore's structure and see how I go from there.