Convert Hashtable

[Joe]

Hi,

I have a Hashtable of string objects that I need to convert to a XML string.
Any ideas how to do this?

Thanks

 

[Truong Hong Thi]

It depends on the schema of the output XML.
You could use one of the approach.
- Use StringBuilder
- Use XmlWriter
- Use XmlDocument

Could you describe the desired output XML schema?

Thi
http://thith.blogspot.com

 

[Joe]

Thanks for the response. The desired output is just the key as the element
with the value. Is StringBuilder the best approach?

 

[Truong Hong Thi]

Hi,

The StringBuilder is simple and best approach to your requirements.
I guess the desired output is like this:
<key>value</key>
If so, make sure the key is a valid XML identifier.
The safer way is <item key="key">value</item>.
Sample code:
const string pattern = "<item key=\"{0}\">{1}</item>";
StringBuilder buffer = new StringBuilder("<table>");
foreach (DictionaryEntry entry in theHashTable)
{
buffer.AppendFormat(pattern, entry.Key, entry.Value);
}
buffer.Append("</table>");
return buffer.ToString();

Hope it helps,
Thi
http://thith.blogspot.com

 

[Marc Gravell]

IMO, using StringBuilder directly is a fairly sure way of introducing
an occasional bug... all you need is a reserved xml character in either
the key or value, and it's broken. That's way too brittle for my
liking.

You can, however, do something like below; fairly hard to break this
via content... also, note that the order of items is not guaranteed by
Hashtable

Marc

Hashtable ht = new Hashtable();
ht.Add("Test", "Something");
ht.Add("Whatever", "abcf");
ht.Add("asd", "adsfgaa");

StringBuilder sb = new StringBuilder();
using (XmlWriter writer = XmlWriter.Create(sb))
{
writer.WriteStartElement("items");
foreach (DictionaryEntry item in ht)
{
writer.WriteStartElement("item");
writer.WriteAttributeString("key",
item.Key.ToString());
writer.WriteValue(item.Value);
writer.WriteEndElement();
}
writer.WriteEndElement();
writer.Flush();
}
Console.WriteLine(sb.ToString());

 

[Truong Hong Thi]

Yes, that is safer. XmlWriter should know how to escape illegal
characters.

 

[Joe]

Thanks for the posts. That makes sense to use XMLWriter and I appreciate
the help.