Technoblog

Linq and untyped DataSets

Lobotommy — Thu, 06 Mar 2008 23:20:00 +0000

As a small update to the previous post - if you don't fancy looking through each table in an untyped dataset then linq is your friend. For instance to join information from two of the yr.no-service tables you can do this:

// Join "time" and "temperature"-tables,
// Get id, temperature, from time and to time
var query =
from time in ds.Tables["time"].AsEnumerable()
join temp in ds.Tables["temperature"].AsEnumerable()
on time.Field<int>("time_id") equals
temp.Field<int>("time_id")
select new
{
TemperatureId = time.Field<int>("time_id"),
Tempearature = temp.Field<string>("value"),
FromTime = time.Field<string>("from"),
ToTime = time.Field<string>("to"),
};

// Simple output
foreach (var tempInfo in query)
{
Console.WriteLine("{0} - {1}:\t{2}",
tempInfo.FromTime,
tempInfo.ToTime,
tempInfo.Tempearature);
}

For more information check this link on MSDN.

Reading weather data from www.yr.no

Lobotommy — Thu, 06 Mar 2008 21:33:00 +0000

Thanks to Sjur for the tip about the weather service at www.yr.no, which actually has a web service publishing pure xml data.

To access a weather service for your favourite location, look it up through the yr.no search and add "Varsel.xml" to the URL.

Access from C# / .Net:

// Load xml from URL
string feedURL = @"http://www.yr.no/sted/Norge/Oslo/Oslo/Oslo/Varsel.xml";
XmlDocument xDoc = new XmlDocument();
xDoc.Load(feedURL);

// Get forecast information
XmlNodeList forecast = xDoc.GetElementsByTagName("forecast");

// Read into dataset
DataSet ds = new DataSet();
StringReader readerStream = new StringReader(forecast[0].OuterXml);
ds.ReadXml(readerStream);

And you have an untyped dataset full of weather information.

Thank you yr.no.

(check the next post for how to read the data with Linq)

A new lobotommy.com

Lobotommy — Fri, 04 Jan 2008 18:43:00 +0000

Stuff happened and the old lobotommy.com had to die. I decided to skip the good, old and stubborn DotNetNuke for something simpler. I didn't find many good alternatives and decided to start coding.

There will be less features behind the new pages, definitely, but hopefully building something from scratch will help me learn some web stuff on the way.