How to get this XML tag?

[Brett Romero]

Rather than this type of tag:

<File Type="Criteria">
</File>

How can I get this:

<File Type="Criteria" />

I only need the closing tag if there will be elements or children
inserted there.

Thanks,
Brett

 

[Jon Skeet [C# MVP]]

Rather than this type of tag:

<File Type="Criteria">
</File>

How can I get this:

<File Type="Criteria" />

I only need the closing tag if there will be elements or children
inserted there.

Could you tell us a bit more about the context? Are you trying to read
the XML, write it, what?

 

[Peter Rilling]

What do you mean? Do you mean when you save the DOM? The two are
equivalent.

 

[Brett Romero]

In C#, when I create an element, it always throws in the closing tag,
which I don't want. The backslash in the opening tag is a shortcut,
which is what I want.

Brett

 

[Jon Skeet [C# MVP]]

In C#, when I create an element, it always throws in the closing tag,
which I don't want. The backslash in the opening tag is a shortcut,
which is what I want.

Again, please say exactly what context this is in. How are you creating
the element? How are you then formatting the document?

 

[Brett Romero]

As for context, I'm only creating an XMLDocument() type and filling it
with elements.

Brett

 

[Brett Romero]

Once again Google Groups is eating my posts. Here's another try:

I create an XMLDocument() object. I give it the root node and add
elements. When I do xmldoc.Save(filename), the file will look like
this:

<?xml version="1.0"?>
<ROOT>
<Person PersonId="100">
</Person>
</ROOT>

Here's my code, which is in a class extending XMLDocument(). That's
why you see the reference to "this":

private XmlDocument xmldoc = new XmlDocument();
private string rootNodeName = "ROOT";
private XmlNode xmlnode;
private XmlElement xmlelem;
private XmlElement xmlelem2;
private XmlText xmltext;

//This is in a method
xmlnode=this.CreateNode(XmlNodeType.XmlDeclaration,"","");
this.AppendChild(xmlnode);
//add the root element
xmlelem=this.CreateElement("",rootNodeName,"");
xmltext=this.CreateTextNode("");
xmlelem.AppendChild(xmltext);
this.AppendChild(xmlelem);

//This is in a method
//add another element (child of the root)
xmlelem2=this.CreateElement("","Person","");
XmlAttribute atrXML = xmldoc.CreateAttribute("PersonId");
atrXML.Value = "100";
xmlelem2.SetAttributeNode(atrXML);
xmlelem2.AppendChild(xmltext);
this.ChildNodes.Item(1).AppendChild(xmlelem2);

I'm passing variables to each of the methods but hard coded values for
simplicity.

Hope that helps and this post.

Thanks,
Brett

 

[Jon Skeet [C# MVP]]

//This is in a method
//add another element (child of the root)
xmlelem2=this.CreateElement("","Person","");
XmlAttribute atrXML = xmldoc.CreateAttribute("PersonId");
atrXML.Value = "100";
xmlelem2.SetAttributeNode(atrXML);
xmlelem2.AppendChild(xmltext);
this.ChildNodes.Item(1).AppendChild(xmlelem2);

The problem is that you're appending an empty text node. If you get rid
of xmlelem2.AppendChild(xmltext); then it works fine.

Here's a short but complete example program:

using System;
using System.Xml;

class Test
{
static void Main()
{
XmlDocument doc = new XmlDocument();

doc.AppendChild(doc.CreateNode
(XmlNodeType.XmlDeclaration,"",""));
XmlElement root = doc.CreateElement ("", "ROOT", "");
XmlText text = doc.CreateTextNode ("");
root.AppendChild(text);
doc.AppendChild(root);

XmlElement person = doc.CreateElement ("", "Person", "");
XmlAttribute attr = doc.CreateAttribute ("PersonId");
attr.Value = "100";
person.SetAttributeNode (attr);
// Uncomment this line to get the "broken" behaviour
// person.AppendChild(text);
root.AppendChild(person);

doc.Save(Console.Out);
}
}

 

[Brett Romero]

Perfect!

How do I add a nested node? For example, if I want to get this
structure:

<ROOT>
<File Type="Criteria" />
<Search Type="Person" Name="My Search" />
<CriteriaCollection >
<Person FirstName="Brett" LastName="Rom" />
<Person FirstName="Jon" LastName="Do" />
</CriteriaCollection>
</ROOT>

Where CriteriaCollection contains another node(?) named Person.

Thanks,
Brett

 

[Jon Skeet [C# MVP]]

Perfect!

How do I add a nested node? For example, if I want to get this
structure:

<ROOT>
<File Type="Criteria" />
<Search Type="Person" Name="My Search" />
<CriteriaCollection >
<Person FirstName="Brett" LastName="Rom" />
<Person FirstName="Jon" LastName="Do" />
</CriteriaCollection>
</ROOT>

Where CriteriaCollection contains another node(?) named Person.

Create the CriteriaCollection element and append that as a child of the
root element. Then create the Person element and append that as a child
of the CriteriaCollection element.

 

[Brett Romero]

Do you have a code example of how that is done? I can't get the Person
node to go.

this.ChildNodes.Item(index).AppendChild(xmlelem2);

ROOT has been created. CriteriaCollection has also been created
successfully. Doesn't the index go from 0 on? When I added
CriteriaCollection, I used an index of 1. Shouldn't the next index be
2...for Person? When I try that, I get:

Object reference not set to an instance of object.

Thanks,
Brett

 

[Jon Skeet [C# MVP]]

Do you have a code example of how that is done? I can't get the Person
node to go.

this.ChildNodes.Item(index).AppendChild(xmlelem2);

ROOT has been created. CriteriaCollection has also been created
successfully. Doesn't the index go from 0 on? When I added
CriteriaCollection, I used an index of 1. Shouldn't the next index be
2...for Person? When I try that, I get:

Object reference not set to an instance of object.

You've *created* CriteriaCollection, but have you appended it yet?
Without seeing your code, it's hard to say...

 

[Brett Romero]

Yes - of which I said an index value of 1 was used:

this.ChildNodes.Item(1).AppendChild(xmlelem2);

where xmlelem2 contains the CriteriaCollection node.

Thanks,
Brett

 

[Brett Romero]

Jon, I see the problem. I was trying to create things off of the
Declaration node, which I'm guessing you can't do.

Here's the finished product:

<?xml version="1.0"?>
<ROOT>
<File Type="Criteria" />
<DataCollection>
<Person FirstName="brett" />
</DataCollection>
</ROOT>

I insert items into DataCollection by using:

this.ChildNodes.Item(1).ChildNodes.Item(2).AppendChild(xmlelem);

However, I can't always be sure DataCollection will be at 2 in the tree
structure. Is there a way to reference it by name instead of index?

Also, <File Type="Criteria" /> is an "Element" of ROOT, not a node.
Yet it pushes DataCollection down to index 2. Shouldn't DataCollection
be the first index off of ROOT? After all, I am saying ChildNodes,
which really shouldn't include elements.

Thanks,
Brett

 

[Jon Skeet [C# MVP]]

Jon, I see the problem. I was trying to create things off of the
Declaration node, which I'm guessing you can't do.

I insert items into DataCollection by using:

this.ChildNodes.Item(1).ChildNodes.Item(2).AppendChild(xmlelem);

However, I can't always be sure DataCollection will be at 2 in the tree
structure. Is there a way to reference it by name instead of index?

You could use an XPath expression - but wouldn't it be easier just to
keep a reference to the element you created?

Also, <File Type="Criteria" /> is an "Element" of ROOT, not a node.

Well, every element is a node. Look at the type hierarchy for
XmlElement...

Yet it pushes DataCollection down to index 2. Shouldn't DataCollection
be the first index off of ROOT? After all, I am saying ChildNodes,
which really shouldn't include elements.

Yes it should - see above.

 

[Brett Romero]

Can you give a code example of what this means or how it can be used:

You could use an XPath expression - but wouldn't it be easier just to
keep a reference to the element you created?

Thanks,
Brett

 

[Jon Skeet [C# MVP]]

Can you give a code example of what this means or how it can be used:

I mean that at *some* point you're creating the DataCollection element.
Save a reference to it in a variable (like you've currently got for
xmlelem and xmlelem2). Then you just need to call
dataCollectionElement.AppendChild(personElement);